Recumbent efficiency

Even if you aren’t able to go as *fast*, are you more efficient on a recumbent bike (even while climbing)? Yes indeed!

Go further per calorie – by going laid back

I’ve been putting in the miles on one of my upright bikes recently, ahead of a race where riding recumbent isn’t an option.

I thought I’d spice things up by swapping a session onto the High Baron, using the same PowerTap wheel to see whether I could make anything interesting of the data.

As I suspected, I was faster on my upright than on the High Baron. I wasn’t going flat out on either bike, since I’ve been doing ten or more rides a week – I was only subjectively investing the same effort on each. The outcome mainly reflects training on one bike (many hours) over the other (very little)… the specific effects of training shouldn’t surprise anyone.

What is more interesting is to compare the power I had to use to achieve each performance.

recumbent_vs_road_bike

The route is a little under 25 miles with just over 1300ft of ascent (40km / 400m). Overall, I managed 17.5mph average for 230W on my upright, compared with 16.7mph for 168W on the High Baron.

I think there was more of a headwind on the High Baron ride, but since that only advantages the recumbent, let’s assume that wind conditions were the same:

Each recumbent mile cost 36.2kCal, versus 47.3kCal for each upright mile.

If I’d been racing myself, I’d obviously have won on the upright, but that’s just one way of looking at a performance. What if I was riding an ultra-distance event where I’m mainly limited by how much I can force myself to eat and how little sleep I can survive on?

For every 36 miles ridden on my upright I’d be an extra 11 miles further down the road on my recumbent (for the same effort) and once performance becomes limited by something other than absolute power (i.e. limited by fuel, fatigue, comfort, or any similar factor) that’s really going to tell.

Even on a 200km brevet my average power in the closing hour or so can be as low as 150-175W. I can achieve that on either type of bike, and then you’ve got to think of the next 200, 400, 1000km…

Screen shot 2013-09-20 at 01.00.43

Convergence on hills, as expected

I’ve previously compared the performance of recumbent and road bike in ‘ideal’ conditions (flat without wind) and found a large advantage in favour of the recumbent (250W vs 150W for the same speed).

On the other hand, I’ve also previously bemoaned terrible performance on all-out hill climbs (the MetaBike took 36% longer), where absolute muscle recruitment and platform efficiency is paramount.

It would be expected then for a mixed route / mixed conditions performance to show much less advantage than the ideal case, depending on the proportion of time spent climbing and the proportion at high speed (where aerodynamics offers significant benefit). A flat TT would be very close to the 100W advantage shown in my earlier test, while a hilly ride would be closer to break-even, or perhaps to disadvantage the recumbent altogether, as in the second test.

Pleasingly this is the case for the rides in question: I was 0.8mph faster on upright for 62W extra, which is a much prettier picture than getting the same speed for 150W extra!

If I isolate the hillier section of the route I see 14.1mph for 350W (upright) against 10.6mph for 245W (recumbent). The lack of absolute power is dramatic, but again, only important if each second counts for its own sake (as in a road race or head-to-head hill climb).

Much more interestingly, the efficiency gap has closed right down, to 89.4kCal per mile (upright) against 83.2kCal per mile (recumbent). But…

The recumbent is still more *efficient* on a 10mph climb, albiet *slower*

Since so many people seem prone to equate slow climbing with poor performance it’s hard to emphasise this too much.

If you’re touring you’re hardly going to ride for four hours dead then stop wherever you are at the roadside. You probably have a destination and getting there a few minutes either side is not important compared with getting there in comfort or for less sweat and toil.

If you’re riding an ultra distance event, it’s not likely that you’re so strong that you can maintain high wattages for days at a time; it’s more likely that you want to get the maximum ‘bang for your buck’ when it comes to spending your body’s limited capacity for exertion.

Only if you’re racing over fairly short distances does absolute power outweigh efficiency.

If we buy into the hypothesis that recumbents reduce the muscle mass you can recruit by isolating your legs (which is one possibility) you can see that they really will start to shine as the miles rack up.

recumbent_efficiency1 (1)

Caveats

Other than the obvious (small sample size, indicative only…) the big caveat here is that I’m still measuring power at the wheel and not at the crank. This means it’s possible that one or other of the bikes is systematically under-reading the effort required. What if the much feared phenomena of drivetrain or frame losses mean that the recumbent really requires an extra 50W at the pedals to hit 250W at the cranks?

It’s impossible to answer this question without access to a crank-based meter at the same time as the PowerTap… if anyone has both and would like to run a few tests, get in touch!

For my part, I don’t really see how such a large difference can be accounted for through drivetrain losses: for starters, an idler that sucked out 50W would get as hot as an old-fashioned incandescent bulb, which is patently not the case.

Certainly there are many questions about recumbent performance that remain unanswered, but hopefully this chips away at another aspect of the problem (even if it raises as many questions as it answers!)

Any comments, as ever, gratefully received…

Vittoria Open Corsa EVO CX (KX & KS) review

In-depth review: Vittoria’s Open Corsa Evo is a great looking, supple, fast-rolling but relatively fragile road race tyre…

Blindingly fast and seriously stylish, but fragile

+ Exceptionally smooth rolling tyres…
… at the expense of durability
BUY:Wiggle [up to 40% off] or Chain Reaction [up to 15% off] (AS PUBLISHED)

Let’s get one thing out of the way – if you buy these tyres and ride them on real roads, it’s likely that at some point you may get a puncture.

While Vittoria have always equipped their headline Open Corsa EVO range of tyres with a puncture strip, these are not intended to be reliable commuting tyres; everything about them is optimised for suppleness and speed, from the microscopic 320tpi carcass to the tread which is so thin it may as well be painted on.

I’m lucky (or foolish) enough to have enough bikes and wheels to be running the Continental GP4000s, Schwalbe Ultremo and three flavours of Open Corsa Evo (CX, KX and KS) just now. See my head-to-head (coming soon) for a direct comparison.

OpenCorsaCover2

Variations

The Open Corsa CX is the popular choice, but you can also get hold of a range of alternative treads on the same carcass: the older KX and KS (slick and more heavily treaded on the shoulders) being the two I have direct experience of.

Vittoria’s extended line now consists of the sr, sl and sc (respectively, wide, slick and tan sidewall).

I can’t tell any real difference between the slick and wet weather versions myself, though it may pain Vittoria’s R&D division to hear that!

Width/weight

The Open Corsa CX isn’t the lightest race tyre, but it’s still very competitive – Schwalbe’s Ultremo is around 15g lighter in the same size, but we’re talking less weight than the change in your pocket and nothing to lose sleep over.

21mm, 23mm and 25mm sizes are all on offer, of which the last two are most likely to be of interest on our cratered roads. Pleasingly, they seem to come up on-size – you won’t buy a tyre labelled 23mm and find it’s actually a rebadged 21mm to keep the weight down.

As always, you may be surprised at the difference in air volume between the tyre sizes:

width relative width relative volume
Vittoria Open Corsa Evo CX 21mm 1x 1x
Vittoria Open Corsa Evo CX 23mm 1.09x 1.19x
Vittoria Open Corsa Evo CX 25mm 1.19x 1.42x

For technical reasons, if all else is the equal a wider tyre will also roll faster. All else is very much not equal between a race and touring tyre, but it applies here: the wider casing bulges proportionally less, so the sidewall deflection is slightly closer to a perfect circle (ideal efficiency).

The 25mm size would be expected to gain around 5% over the 23mm for this reason. Those of you who are into longer days on the bike will greatly appreciate the extra comfort combined with extra speed! (Obviously, you need the clearance in your frame and forks…)

Rolling resistance

Vittoria are proud to claim that the Open Corsa is “provenly the fastest all-round racing tire available” and though you should take that with a grain of salt, it has performed very strongly in third party tests (including some quite geeky ones you can find online).

The carcass has been made at a phenomenal 320TPI, which makes it almost 3x thinner than the carcass on a Continental GP4000s. This reduces rolling resistance (at the cost of strength) and of all the tyres I’ve spent serious time on, the Open Corsa is certainly the one which leads the way when it comes to a feeling of raw speed.

As above, having the option of going wider allows for even faster rolling tyres – the disadvantage of an increased cross-section into the wind shouldn’t worry you unless you’re riding time trials (in which case your bike might not even fit a 23mm tyre, never mind a 25mm one!)

As I’ve written before, the Open Corsa (like the GP4000s and Ultremo) are measurably faster than some tubulars (such as the Continental Competition) which should tell you all you need to know about how fast they really are.

corsa3
Open Corsa Evo CX (fine diamond / herringbone tread)

Comfort

Standard caveat: The Vittoria Open Corsa Evo CX is a race tyre. It’s not designed to be comfortable in the same way that a touring or utility tyre is (if that’s what you want, I’m afraid you need a different bike!)

That said, of all race tyres I’ve tried the Open Corsa stands head and shoulders above the others for its smooth ride at a given pressure and width: it’s like riding on a wider size altogether (or letting 15psi out!)…

While I certainly wouldn’t tour on them, so long as you’re happy with the relatively limited mileage, they make a great choice for long days in the saddle.

Grip

In the dry the Open Corsa CX has great grip – things are less clear in the wet, where I find them to be less confidence inspiring, especially compared to the super tacky GP4000s or Ultremo.

That said, they’re streets ahead of a more basic (and hard wearing) commuter tyre. Any of these three would be perfectly acceptable, but when you ride them head to head on greasy tarmac… the Open Corsa is edged out a little, in my opinion.

corsa1
Open Corsa Evo KX (cosmetic shoulder tread, slick centre)

Flat resistance

I want to say that it’s only a matter of time, but that’s probably being a little unfair on a tyre which is designed from the ground up to serve a purpose where the ocassional flat is quite acceptable.

If you want a heavy and protected tyre, they’re on the market too.

That said, I do think the Open Corsa EVO is more vulnerable than either of my recommended alternatives (the Continental GP4000s and the Schwalbe Ultremo).

In common with all true race tyres the sidewalls are unprotected: vital to minimise rolling resistance, but exposing them to risk of damage compared with heavier and less supple tyres.

There are sufficient reports online of people tearing these tyres up that I think it’s safe to conclude they are at least *somewhat* more vulnerable than, say, the GP4000s. It’s really quite hard to be objective because people with the worst luck shout loudest!

I do ride my Corsas on less than perfect roads (including some short bits of urban path which never see a sweeper) because I don’t believe it’s worth paying for top-quality tyres and sitting them on the mantlepiece.

corsa4
Open Corsa Evo KS (slick tread)

Durability

Tread thickness is directly linked to rolling resistance. The Vittoria Open Corsa Evo emphasises going fast, so it has relatively little rubber!

As mentioned above, watch the sidewalls.

I’m hoping to get 2000 miles on the rear tyre which I’ll consider fair innings. At the end of the day they are a consumable item, and we accept the flipside of high performance with eyes open. 🙂

Conclusion

With the Open Corsa EVO CX (and sister tyres in the same line), Vittoria has really hit the ball out of the park on the performance front. Nothing else will get you as close to the feel of tubulars without actually riding on them.

In fact, I prefer my Open Corsa -equipped wheelset to my tubs because they’re so close in feel that all I’m left with are the many downsides of riding a tub…

They look fantastic. If you want a really good looking race tyre look no further!

+ Exceptionally smooth rolling tyres…
… at the expense of durability
BUY:Wiggle [up to 40% off] or Chain Reaction [up to 15% off] (AS PUBLISHED)

Vital Statistics

Note: On a 15mm rim the 700x23c measures 23.5mm

Folding only:

ETRTO (mm) Imperial (“) Pressure (bar) Pressure (psi) Weight (g)
21-571 650x21c 8-10 115-145 185
21-622 700x21c 8-10 115-145 195
23-622 700x23c 8-10 115-145 210
25-622 700x25c 8-10 115-145 220

 * note that coloured rubber options are available in 23-622 / 700x23c only.

Ultra Gatorskin vs GP4000s

Continental GP4000s or Continental Ultra Gatorskin? Which of these road bike tyres is best for you, and where’s cheapest to buy them?

Continental: puncture protection or all-out racer?

Recently I posted an in-depth review of the Continental GP4000s after they appeared on a wicked 35% discount on Wiggle.

I’ve also just posted an in-depth review of the Continental Ultra Gatorskin… now with Chain Reaction doing the honours with a tasty 30% discount.

These two tyres may have the same manufacturer but they are very much designed with different purposes in mind. As a long-term user of both the GP4000s and Gatorskins, I decided to put together this overview to help you decide which tyre is right for you.

gp4000s-gatorskin-feat

Comfort / handling: GP4000s II

It’s important to bear in mind that you can get the Gatorskin in wider sizes, but if you stick to matching widths, the supple racing construction of the GP4000s gives it the edge in sheer ride quality.

A wide Gatorskin will absorb more road chatter, but you lose the superb grip of Continental’s Black Chilli compound – particularly noticeable when the road gets greasy.

Durability: Gatorskin

Continental’s Gatorskins are designed to provide respectable speed with an emphasis on toughness, so as you’d expect they’re much more likely to go the distance than the GP4000s.

Both tyres perform well when new, although the GP4000s is lacking the sidewall protection of the Gatorskin. Ultimately the thin racing tread on the GP4000s wears out sooner than the Gatorskins, however, and when that happens, it’s time for a puncturefest!

gatorskin-fitted

Weight: GP4000s II

Let’s be completely honest here – the grams separating the 205g GP4000s from the 260g Gatorskin won’t make an appreciable difference to you, regardless of the fact that it is rotating weight.

50g is just not a significant component of your power-to-weight ratio given that the mass of rider plus bike for the average reader of this site is probably going on for 100,000g (100kg).

The superior construction of the GP4000s gives it a more supple and lively ride, but don’t confuse that for the effect of weight alone.

Puncture Protection / Sidewall Protection: Gatorskin

The Gatorskin is the clear winner here, with a tough breaker strip and rim to rim sidewall protection. The GP4000s does feature a Vectran fibre breaker layer which does an excellent job defending the tyre from unwanted penetration, but at the end of the day, it is a race tyre and it’s not designed to spend time amongst fields of broken glass.

If your route is at all rough, then hedging against sidewall damage or a blowout with the Gatorskins is certainly an option. You can take your chances with a pure race tyre (and I do, regularly) but don’t blame them if they get torn up.

Continental GP4000s in the mud
(GP4000s after a muddy ride. They *can* do this, but don’t get upset if you ride them to destruction…)

Rolling resistance: GP4000s II

There’s no question that Continental hit the ball out of the park with the GP4000s – a recipe that has remained unchanged for years but still performs at the highest level when it comes to the all-important figure of rolling resistance.

The Gatorskin is a conscious effort to make a tyre with respectable turn of speed yet offering the puncture protection many riders demand. It’s no secret that this comes at a cost both in comfort and in speed versus an all-out racing tyre, and so it is in practice.

That said, the Gatorskin is still a perfectly respectable performer, worlds away from the likes of a heavy duty Marathon Plus. (On the other hand, the Marathon Plus really is a guarantee against punctures, unlike the Gatorskin – choose your compromise!)

Styling: GP4000s II

This may be a bit of a silly category since Continental are hardly known for making great looking tyres (just ones that perform well). Ultimately however, the GP4000s does look a bit more the part with its silver print – to me. Talk about eye of the beholder!

Not that cycling has ever been about looks, right?

Conclusion: GP4000s II

The fact that you’re even considering the Gatorskin (rather than a real heavy duty tyre like a Schwalbe Marathon) suggests you are pretty interested in how fast you can make your bike go.

If you want a supple, nimble, rapid bike with reasonable puncture resistance the GP4000s has your name all over it. It has enough puncture protection to keep you smiling so long as you’re discerning about where you ride it – not through the local tip, please!

While the Gatorskin does have superior protective properties, for me this isn’t enough to offset the difference in feel between the two tyres. I’d rather have a pair of GP4000s for going fast and a pair of Marathons for steamrollering through town than one pair of Gatorskins that still left me a bit worried about punctures and a bit down on speed at the same time.

Looking for a good discount?

At the time of writing, both Chain Reaction and Wiggle have hefty discounts on the GP4000s and Gatorskin tyres. Take a look:

Continental Ultra Gatorskin review

A tyre which tries to strike that most difficult balance – tough enough puncture protection to satisfy the everyday rider, while catering for the demands of enthusiasts…

Classic rolling resistance vs puncture protection compromise

The Continental Ultra Gatorskin is a tyre which tries to strike that most difficult balance – tough enough puncture protection to satisfy the everyday rider, while catering for the demands of enthusiasts who insist on a brisk and low rolling-resistance tyre.

Available in a range of widths and with budget wire construction as well as folding kevlar beads, the Gatorskin is a strong contender as a relatively rapid commuting or training tyre.

gatorskin-feat (1)

I personally like my tyres to be either very fast or very tough; after a few years using the Gatorskin I now tend towards either a ‘pure’ racing tyre like the GP4000s or something really tough, like a Marathon Racer.

However, I just retired a pair of Gatorskins from my wife’s commuter after three years’ use in central Edinburgh… and just one flat!

If you have one bike to do it all, they’re certainly worth a look.

(At the time of writing, Wiggle have a 25% discount while Chain Reaction are doing 30% off).

Width/weight

The Ultra Gatorskin is pretty competitive in weight terms – a 23mm wire bead version comes in at 280g, whereas the Specialised Armadillo varies (400g for the All Condition, 260g for the Elite in the same width). It’s not actually all that much heavier than the full race construction GP4000s, at 205g (23mm) – although the tyre construction makes them significantly slower.

The range of widths allows you to cater to your particular purpose, with quite a bit jump in volume between the smallest and largest sizes:

width relative width relative volume
Continental Ultra Gatorskin 23mm 1x 1x
Continental Ultra Gatorskin 32mm 1.39x 1.94x

For technical reasons, if all else is the equal a wider tyre will also roll faster. All else is very much not equal between a race and touring tyre, but it applies here: the wider casing bulges proportionally less, so the sidewall deflection is slightly closer to a perfect circle (ideal efficiency).

The 25mm size would be expected to gain around 5% over the 23mm for this reason.

continental-gp4000s-road-tyre

Rolling resistance

The Continental Ultra Gatorskin doesn’t quite have the buttery feel of a top race tyre, but it’s not too bad: only if you concentrate does the deadening effect of the extra protection become obvious while riding.

Compared with a wider tyre such as the Marathon Racer, the Ultra Gatorskin definitely retains the feel of a narrow road bike tyre. So, again it comes down to the compromise. How much of the feeling of a true road tyre are you willing to give up, and for how much puncture protection in exchange?

Comfort

To state the obvious, road tyres like this are not designed to emphasise comfort.

If anything, the Ultra Gatorskin works out a bit less comfortable even than a pure road tyre, because adding armour to a tyre makes it less supple. However, fitting these tyres in a wider size will go a long way towards providing a respectable mix of comfort and performance.

Grip

The Ultra Gatorskin doesn’t benefit from Continental’s tacky Black Chilli rubber or from fancy dual-compound construction; it sticks to the basics with a slick natural rubber tread.

Reviews of the grip of the Gatorskins are mixed. I’ve always found performance to be good, except when a road is really greasy (at which point all cheap or durable tyres will start to struggle). In exchange the rubber tread lasts a lot longer. Take your pick!

It’s important not to underestimate the advantage of a tougher (or wider) tyre when considering grip, simply because it puts you in a position of needing absolute grip less often – you don’t need to swerve for broken glass quite as much with a puncture-resistant tyre, and you don’t need to dodge potholes as much with a wide one.

gatorskin-fitted

Flat resistance

The Poly X Breaker provides flat protection in the central part of the tread, while DuraSkin weave provides cut resistance for the whole carcass.

I’ve personally always been pleased with the performance of the Ultra Gatorskin in terms of flat prevention – often just one or two flats through the life of the tyre before a sudden rash of them indicates it’s reached end of useful life.

The pair pictured on this page have just finished a three year shift of daily commuting in central Edinburgh. Loads of cuts but just one flat at the end which prompted me to inspect the carcass (and decide some of the slashes in the tread were just a little big for comfort).

For the money, it’s right on the money 🙂

Durability

There’s more depth to the slick tread of the Ultra Gatorskin than is found on many road tyres, and as a consequence you can expect to enjoy higher mileages – mine have always lasted for a surprisingly long time before cumulative cut damage makes me too nervous to continue, or I get a spate of flats as a few pieces of glass penetrate all around the same time.

While I’ve never had any trouble myself, there are plenty of reports (as always) on the internet in which people recount fitting this tyre and almost immediately writing it off on a pile of glass. All I can say is, first, there’s a hefty element of luck involved; second, don’t assume that just because your tyre has a puncture belt that you can ride it over glass with impunity. It will eventually get through almost anything!

gatorskin-cuts1
Neither of the cuts above or below, which are typical of the damage covering this tyre after three years’ use, got through to the tube. Good work Continental!

gatorskin-cuts2

Conclusion

With respectable speed, respectable puncture resistance, respectable weight and a respectable price, the Gatorskin is an all-round balanced compromise and you can see why Continental are able to claim it’s the best selling 700x23c tyre in the UK.

If you want to ride fast on a supple race tyre, consider the GP4000s.
If you want to have ultimate puncture protection, you need something like the Marathon Plus.
If you want a really cheap tyre, just buy whatever’s on the best offer today.

If, like many, you want a balance of all of the above, you should definitely be taking an interest in the Continental Ultra Gatorskin.

At the time of writing, Wiggle have a 25% discount while Chain Reaction are doing 30% off.

Go get ’em…

Vital Statistics

Note: On a 15mm rim the 700x23c measures ~22mm

Wire:

ETRTO (mm) Imperial (“) Pressure (bar) Pressure (psi) Weight (g)
28-559 26 x 1.2 max. 7.5 max. 115 350
23-571 650 x 23c max. 8 max. 120 250
23-622 700x23c max. 8 max. 120 280
25-622 700x25c max. 8 max. 120 300
28-622 700x28c max. 7.5 max. 116 360
32-622 700x32c max. 7 max. 102 365
32-630 27 x 1 1/4 max. 8 max. 120 330

Folding:

ETRTO (mm) Imperial (“) Pressure (bar) Pressure (psi) Weight (g)
23-622 700x23c max. 8 max. 120 220
25-622 700x25c max. 8 max. 120 250
28-622 700x28c max. 7.5 max. 116 320
32-622 700x32c max. 7 max. 102 325

 

CycleOps PowerTap Pro review

The ability to optimise your riding position, equipment choices and even your nutrition make any power meter into a tremendously powerful tool…

You can do so much more with a power meter than train, but it’s a good start. The ability to optimise your riding position, equipment choices and even your nutrition make any power meter into a tremendously powerful tool, one that’s increasingly prevalent amongst today’s keen amateurs.

When it comes to choosing a power meter, in 2013 your choice still boils down to an expensive crank-based one (SRM, Quarq, etc) or the more reasonably-priced CycleOps PowerTap hub-based system.

There are two basic choices in the current range, the Pro (reviewed here) and the far more expensive G3 series (which are lighter and easier to service).

Wiggle have a 24% discount at the time of writing (check with Chain Reaction too, as offers come and go).

Since their introduction in the early 1990s, power monitors have supplanted heart rate monitors as the ultimate measurement of choice for cyclists interested in the most efficient path to smart training and improvement. … If you’re reading this, you already know it’s the way to go for smart and efficient training. (pez.com)

Compared to other Power meters

For the purposes of 99.99% of people reading this review (that means you) the accuracy differences between power meters are insignificant. That doesn’t mean that they don’t exist (or that they might not be important in some specific circumstances) but unless I made my living riding, I can’t say I’d worry about it when there are so many more important things that impact your training.

powertap (1)

Consistency is important, but accuracy? Not so much. If you look around online it doesn’t take long to realise that almost everyone doing measurements isn’t able to / bothering to control confounding factors to within the stated accuracy of the meter anyway. Given the huge cost difference, getting a PowerTap hub-based meter rather than a very expensive crank is a complete no-brainer. Really, what are you thinking? 😛

German company Power2Max are offering a comparably-priced crank but it’s still early days for them, with reports of consistency issues (which is much more important than absolute accuracy – it doesn’t matter much if your reading is always 10W too low, so long as it reads the same thing for each ride!).

That said, the big advantage of a crank-based meter is that you can swap wheels (training vs race) and measure the difference between, say, deep and shallow rims with ease. So I’d love to get some time on a Power2Max and post a detailed head-to-head. (Hey Power2Max people!)

Compared to other PowerTap hubs

If you already have an Ant+ compatible PowerTap hub, there’s little advantage to be gained from a switch to the PowerTap Pro. The weight saving is simply insignificant (40g versus the old Pro+). On the other hand, if you have an old wired PowerTap model then this is definitely going to offer a great improvement, as you can tie it with a wide variety of head units, particularly Garmin’s excellent Edge GPS series.

For my money, I’m not too sure the expensive G3 series is as sensible a choice – it saves a little bit of weight, but at hefty cost. Why not spend the same money upgrading other parts of your bike for much greater weight savings?

See the section below for details of the weight implications anyway…

powertap4

Weight

A nice lightweight rear hub for a road bike comes in at about 275g, if you want something reasonably practical and not overly exotic. By comparison the PowerTap Pro weighs a relatively hefty ~450g, a premium of around 175g. What will that cost you in terms of speed?

It’s easy to calculate but I’ll give you an example working here… say you weigh 75kg and your bike weighs 8kg, the difference between wheels being 175g for the PowerTap hub. Calculate a ratio between the two weights:

(75+8+0.175) : (75+8) = 1.002:1

Pick a climbing speed for the PowerTap hub (15mph) and multiply by 1.002 to get the climbing speed for the normal wheel for equal effort (15.03mph). At the end of a 15 minute steady climb the PowerTap wheel would be 0.03*0.25 = 0.0075 miles behind (around 12 meters).

15mph is 6.7 meters per second, so the PowerTap Pro loses two seconds every 15 minutes of solid climbing. That’s the physics – the effect is obviously negligible on anything less than a steep hill.

The ability to pace yourself according to your established power threshold easily offers the ability to pull in two seconds every 15 minutes. I realised an improvement of seconds per minute due to superior pacing when I started hitting Strava with my PowerTap.

Flexibility

You’ll hear this one of two ways:

  • The PowerTap is built into a wheel. This is bad, because you can either have a training wheel or a race wheel but not both.
  • The PowerTap is built into a wheel. This is great, because you can measure power on any of your bikes in moments (try that with a crank!)

At the end of the day it depends what your priority is. You want to maximise the amount of time you spend on the bike with a meter, so plan to build a wheelset that suits your own purpose. Hopefully my weight section above has helped convince you that “even” a PowerTap Pro is quite suitable for racing on, and training too…

If you only have one bike, that would make the case for a crank-based meter stronger, but if you have multiple (or think you might upgrade to a bike with a different bottom bracket format, for instance) then the PowerTap’s a clear winner.

powertap1
With sufficient pain, you can improve the area under the graph…

Calibration / Pairing

This couldn’t be easier: tell your head unit (Garmin, iPhone, Android or other) to search, then spin the wheel. It will acquire immediately.

Calibration instructions are provided. It’s not something that will give you any issues – the important thing about a power meter is not absolute accuracy in any case, only consistency (an improvement of power by 5%, whether your hub reads 10W lower or higher than the guy next to you, is still an improvement of 5% and you will still be climbing at least 5% faster!)

Expense

There’s no denying that the PowerTap is an expensive tool for the vast majority of us who aren’t racing professionally. That said, compared with the money you’ve probably spent on bike gear over the years, is it really so much to allow you to record with accuracy and precision how much force is going through your back wheel, with all the analytical power that places at your disposal?

You’re saving a lot of money compared with paying for a coach (and if you do have a coach, you’ll both get a huge amount more out of your training). It might either free up some training time for other life pursuits (or household chores!) if you just want to intelligently match the riders in your regular weekend group, or allow you to make a step change in performance if you keep putting in the same hours.

I’ve found the pacing provided by a PowerTap to be a tremendous help on long distance events (even though, by and large, I use a non-PowerTap wheel on those events – it’s improved my ability to ‘feel’ effort no end).

In short, if you’re even vaguely keen on measuring and improving your performance the PowerTap is the only game in town. Whether it’s worth the money or not to you personally? Only you can say!

As I mentioned above, these hubs are often on offer, which could reduce the sting. Wiggle have a 24% discount at the time of writing (check with Chain Reaction too, as offers come and go).

I worried that I might regret my first PowerTap due to the cost, but I’ve never looked back. 🙂

Service / repair

One advantage of the PowerTap G3 series is that the electronics are located in the hub cap only, so it’s easy to detach this and return for servicing if you are unlucky enough to find a fault. The PowerTap Pro, on the other hand, would require you to return the whole wheel for an electronics fault. Fortunately, there’s a UK service centre!

I haven’t been in this situation, but there are plenty of customer reports praising their rapid turnaround, so I’m not sure it’s really a reason to buy a hub that costs a massive amount more. How inconvenienced would you be to have to ride without power for a week?

Battery changes (standard coin battery) are straightforward while the bearings can also be serviced by your local shop provided they use a press and don’t slam the electronics around with a mallet. Which should be obvious really.

powertap

Conclusion

The CycleOps PowerTap hub is not a cheap bit of kit by any means. Nevertheless, despite being (only) a keen amateur, I haven’t suffered a moment’s remorse.

I’ve been able to accurately calculate the minimum calorific cost of my commute (800kcal / day), benchmark the performance of different riding positions and equipment choices, and more (sometimes I even use it to train! 😉 )

If you’re serious about understanding what’s going on when you ride, and becoming a stronger rider, I totally recommend it.

Wiggle have a 24% discount at the time of writing (check with Chain Reaction too, as offers come and go).

Like me, you’ll soon forget the cost.

Vital stats: PowerTab hub weights

Hub Weight
2012 Pro 446
G3 325
G3C 315
Pre-2012 range
Elite+ 624
Pro+ 485
SL+ 412
SLC+ 402

Recumbent position power loss

A short article comparing preliminary power tests of recumbent and upright platform, and discussing recumbent power loss.

This is another article in the vein of the 1 minute hill climb, looking at (but not necessarily answering!) issues around recumbent and upright power production.

Background

I haven’t ridden many recumbent miles since the 200km Erit Lass last September, but I have kept up my five mile commute on my upright hack bike that whole period. I consider myself to be quite badly out of recumbent-specific conditioning (despite coming in 21st in my category on the Tour o’ the Borders).

tour of the borders recumbent
The new Optima High Baron cleans up the field on the Tour o’ the Borders…

As I recently started getting serious with the Optima High Baron, I thought it might be interesting to benchmark my power on the two platforms now, and look at whether it converges over time. In my opinion it’s also an interesting window onto the experience of novice recumbent riders who try to transition from their upright bikes expecting a gain in performance.

I’m going to display the data from two PowerTap stationary trainer intervals. The sessions were uncontrolled except that I tried to shoot for my highest average power in each case over a 12.5 minute interval (interestingly, in both cases I ended up picking things up at the end – bad pacing?).

The intervals were on different days, first thing in the morning before work. For what it’s worth the recumbent went first…

Interval Upright Recumbent Power loss
1 minute 355W 296W 19.93%
5 minutes 290W 239W 21.33%
10 minutes 275W 220W 25.00%

A 25% drop in power means that on a climb the upright would pull away one mile for every four miles the recumbent rider travels – it’s a pretty big gulf!

Context

[edited to add this section, as I felt the article originally was lacking in context]

Consider this: received wisdom often tells us that recumbents do not climb as well as conventional bikes because they are heavier, and/or because they are less efficient due to some combination of frame flex, or drivetrain friction due to the idler systems involved. However, I believe this is demonstrably false.

In the first case, we can categorically evaluate the impact of extra weight using simple science, with or without a power meter (see my article on bike weight and performance).

However, with a power meter it’s possible to precisely define both limiting factors of weight and power output and, as in this case, I believe climbing performance will always turn out to be limited by reduced power output and not by increased weight.

However, by measuring power at the wheel and not at the cranks we do leave open the possibility that the drivetrain is consuming 50W or more in increased friction, however unlikely that may sound. My answer to this (and ultimately to all questions of inefficiency in the recumbent bike proper) is that if the same work is being done by the human body, but it’s just being lost somewhere en-route to the road, we should see a very similar physiological impact to the activity.

This is manifestly not the case, as in the two intervals discussed below: the recumbent one is not only far fewer watts, it had manifestly lower cardiovascular demands (even though it was as hard as I could push the pedals), relative to the upright session.

I’ll follow this up as promised with something that includes HR, although that’s of only limited use in evaluating demands on the body, as we’ll see…

[back to the original article:]

Torque vs cadence

torquepower

Comment

Don’t read too much into a sample size of one, however, counter-intuitively the power gap increases with duration. You would expect proportionally greater failure to generate power over short periods if the upright position simply allowed a greater mass of muscle to be recruited (albiet inefficiently), as many hypothesise.

As I’m sure the difference between recumbent and upright riding position tends towards equality in the very longest events, this initially suggests a reverse-U shape. Clearly more investigation is required… I personally think this is showing both a fundamental difficulty in producing recumbent power but more importantly a significant and specific lack of conditioning in a couple of key muscles that is inhibiting overall performance.

While it’s tempting to blame inefficiencies in the physical recumbent drivetrain, I don’t think this is a significant issue because my cardiovascular reaction to these two intervals was very different – the upright session left me feeling nauseous and faint where the recumbent one left me a bit sore but after a short break, I felt able to match it again.

Exactly not what you’d expect if the power output was actually the same in both positions, but the recumbent frame was losing it to friction ‘upstream’ of the PowerTap.

I’ll make an effort to do proper 20 minute max efforts on both platforms and keep an article update with how the figures change and (hopefully) converge as I start to assume better form.

Upright stationary trainer interval – 12.5 minute best effort

Edit: I’ve added a screen grab from Golden Cheetah to the one from Ascent (I had to crop the latter quite aggressively to get it to fit):

recumbent-power-comparison-new2

gc_df

Recumbent stationary trainer interval – 12.5 minute best effort

Edit: I’ve added a screen grab from Golden Cheetah to the one from Ascent (I had to crop the latter quite aggressively to get it to fit):

recumbent-power-comparison-new1
gc_bent

Food for thought! I’d love to hear any thoughts in the comment section below:

See also discussion on this post in BROL.

Tour o’ the Borders: sportive EPIC

Little did I suspect I would be fording a river sweeping knee-deep across the road, while the wind made it almost impossible to stand…

Heroic sportive cements reputation as a modern classic

I knew the weather was going to be taxing before we even got the start line on Sunday’s now-legendary Tour o’ the Borders. Although there was no question of missing out on a great day on the bike, little did I suspect I would soon be fording a flooding river sweeping knee-deep across the road while the wind conspired to make it almost impossible to stand!

tour of the borders 2013
Photo courtesy Tour of the Borders (via Facebook)

The event was based at Peebles High School which provided welcome shelter from the rain, and of course the canteen was doing a roaring trade in coffee and bacon rolls! The organisation of this sportive was first class – it was the work of moments to register, get my pack of goodies and ride essentials- race number and timing chip. No queues!

As my first sportive, I had a few concerns about the type of riders or reception we might meet but the whole day was very friendly. The Tour o’ the Borders did have plenty of roadies but there was no shortage of normal (ish!) looking people – flat bars, tandems, recumbents welcome! I even saw one chap with his helmet on back to front, which is always reassuring (I’m sure someone told him before he tried to start the route…)

The atmosphere was great (even if, on the course, it’s been suggested there was more of a “blitz spirit”)… we’ll definitely be back next year!

The Route

The Tour o’ the Borders has two routes, long and short (although at 50 and 70 miles, the main thing that separates them is actually the number of climbs!)

Each takes in the long winch over Paddy Slacks (in both directions), the steady grind up Berry Bush, and the lovely Witchy Knowe climb from Kirkhope back over to the Yarrow valley. In addition, the long route throws in a couple of climbs between the Ettrick valley and Ashkirk as well as “the Wall” which rears up between Ashkirk and the feed stop at Kirkhope.

touromap

Whichever option you choose, the roads are near deserted (next year they will actually be closed) and the surfaces are OK (compared with, say, Edinburgh’s roads!) – a great day out is all but guaranteed…

Not that the hills would be the main challenge this year… 🙂

Out on the course

9am came around and it was still raining buckets with a fierce wind as we regretfully left the warmth of the canteen. Lined up in the starting paddock together with a group on normal bikes, the wind was already strong enough in the car park that I had to unclip to keep myself upright!

Once out on the course, the sheltered few miles to Traquair had me lulled into a false sense of security. When we turned onto Paddy Slacks, the wind was absolutely hammering through the pass accompanied by stinging hail.

At this point the Baron started to shine and I picked off an endless stream of riders on the ascent, despite keeping my power low. The most challenging thing was negotiating the huge amount of debris that had been washed onto the road (while trying not to get blown off it!), as well as the steady stream of abandoning riders coming the other way.

I actually had to pedal downhill to the Gordon Arms!

tour of the borders 2013
Photo courtesy Tour of the Borders (via Facebook)

Berry Bush was probably the worst headwind of the ride – totally exposed and relentless. It took twenty minutes to climb averaging just 10mph and often had me wishing my inner ring was a bit smaller than 39t!

Surprisingly few riders were working together, although just before the summit a group formed that came through and gave me a welcome boost to the top (thanks!) 🙂

The respite on the descent into the Ettrick valley was delicious. The roads here are absolutely fantastic – narrow and twisting but not so much that you’re worried about what might be coming the other way… just perfect for bikes.

However, with only two of the route’s seven climbs completed we came across a marshal flagging riders down to warn of flash-flooding on the long route, and recommending we cut it short. As an audax rider I’m used to a bit of weather and decided to push on, but was admittedly unprepared for the sight of the river Ettrick bursting over its banks and running across the road… did this put paid to my chances of getting a time on the long course?

tour of the borders 2013
Photo courtesy Tour of the Borders (via Facebook)

In a past life I used to kayak these rivers for fun (preferably with fewer fences though) so I decided to go for it.

Fortunately it wasn’t too deep to stand – it only came up to knee height – but even so I had to use the bike as a rolling tripod to let me lean into the wind and current. And I’d been thinking that sportives were a soft option – how wrong!

tour of the borders 2013 flooding
Photo courtesy Tour of the Borders (via Facebook)

As the air temperature wasn’t too low, I warmed up immediately on the other side, and started to enjoy the huge tailwind which swept me around that half of the course. I didn’t bother pedalling above 20mph so needless to say I didn’t do much pedalling until I hit the short climb from Alemoor reservoir, just before the turnoff to Ashkirk.

The road to Ashkirk passes over a high moor and was extremely fast despite the conditions – by this time it seemed that I’d been going for about an hour without really having to pedal. From Ashkirk the riding got tough again as I turned back into the wind and hit “the Wall”. This climb was too steep for my 39t inner ring given the conditions, with one ramp at 1:6 (over 15%). Still, the rain was letting up now and this made things much more cheerful.

Course highlight – a tree had fallen across the road but the branches were hacked away to allow you to ride underneath (not by the organisers, I’m sure!).

Around this time I started to pick up the slower riders who had made it through before the flood, although none of them were going as fast, so I missed out on any sort of draft from here to the finish.

The feed stop in Ettrickbridge was fantastic – a full range of soup, sweet and savoury food at the foot of the event’s toughest climb and shelter from the rain too! Thanks so much to all the locals who were manning this…

By this time, riders were being rescued from the flooding by tractor (!):

tour of the borders 2013
Photo courtesy Tour of the Borders (via Facebook)

The climb up Witchy Knowe was a steady grind and I was finally papped by a photographer at the summit (I haven’t seen any of these photos online though, at all?) before the streaking descent to the Yarrow was testing my brakes.

The sun was out now and the ride up to the Gordon Arms was refreshing despite the headwind – I was steadily passing riders from the short course now which kept me motivated. Birling up Paddy Slacks with a gale at your back is fantastic, and the descent seems to go on for an eternity!

Last but not least was the return from Traquair to Peebles – I’d hit my stride now and averaged 20mph (the wind was doing funny things) right through to the finish. There were a couple of huge puddles to hammer through – again one had photographers at it, although I haven’t seen any shots from there either.

Then it was on to welcome food and dry clothes.

Mission COMPLETE!

tour of the borders recumbent
Photo courtesy Laid Back Bikes.

Summary

270 finished the long course and 360 the short course – an impressive number considering the conditions. Some went round the long course in 3:40 which is quite incredible given the wind (3:20 would be evens!)

I was 21st in my category. No doubt complemented quite a lot by the fact that few riders were foolish enough to follow me through the river… although my Garmin says I lost ten finishing places due to the delay, so who knows…

Next year with closed roads and (hopefully) better weather we’ll see what’s what! 😛

Don’t miss this event in 2014. Friendly, well organised, and great roads. It’s going to be fantastic.

GP4000s vs Ultremo ZX

Continental GP4000s or Schwalbe Ultremo ZX? Which of these top-flight road bike tyres is best for you, and where’s cheapest to buy them?

Continental or Schwalbe: who makes the best road tyre?

A few weeks ago I posted an in-depth review of the Continental GP4000s II after they appeared on a wicked 35% discount on Wiggle.

Last weekend I posted an in-depth review of the Schwalbe Ultremo ZX … this time, it was Chain Reaction doing the honours with a tasty 33% discount.

These two tyres are very much targeted at the same audience. As a long-term GP4000s rider and a more recent convert to the Ultremo ZX, I decided to put together this overview to help you decide which tyre is right for you.

Schwalbe Ultremo ZX photo

Comfort / handling: Ultremo ZX

I can’t fairly compare these two tyres on comfort as I don’t have matching sizes to ride side-by-side at the same time.

However, in my mind there’s absolutely no question that the Ultremo ZX wins in the comfort stakes. Measuring up slightly wide on a given rim (where the GP4000s measures slightly narrow) means the Ultremo simply holds more air than its Continental rival, and that translates directly to improved comfort on the bike.

Don’t underrate this. For all but the shortest events, and especially at the amateur end of the spectrum, comfort translates directly into greater performance (only in cycling are people mad enough to question this).

Combining width with tacky rubber gives the Ultremo wonderful handling over rough ground and into corners (regardless of whether or not Continental’s Black Chilli rubber is actually more tacky).

Descending confidence on Ultremos is unparalleled in all weather.

Durability: GP4000s II

There’s no question here really: according to all sources the Continental GP4000s is significantly longer lasting than the Ultremo ZX, although estimates as to the lifespan of both tyres vary wildly online.

I can’t be conclusive personally; though I’ve run through many sets of GP4000s tyres and get around 2500 miles on the rear, I’m still on my first set of Ultremos. They’re looking brand new and uncut after several hundred miles on rough roads, but until I wear them through to the carcass my own jury has to remain out.

Continental GP4000s in the mud

That said, I’ve got nothing to indicate that world+dog is wrong on this one.

Weight: Schwalbe Ultremo ZX

Let’s be completely honest here – the handful of grams separating the 205g GP4000s from the 195g Ultremo ZX won’t make an appreciable difference to you, regardless of the fact that it is rotating weight.

10g is just not a significant component of your power-to-weight ratio given that the mass of rider plus bike for the average reader of this site is probably going on for 100,000g (100kg).

That said, I won’t deny it’s nice to have light parts. If you’re one of the growing number of wide tyre affectionadoes, you may be interested to know that the 28mm Ultremo ZX  is virtually the same weight as the 25mm GP4000s…

Puncture Protection: tie

Both tyres are race models and not designed for riding over fields of glass or thorns. That said, the GP4000s features a Vectran fibre breaker layer which does an excellent job defending the tyre from unwanted penetration.

The Ultremo ZX features a similarly advanced fibre layer (called “V-Guard”) and by all accounts this does a respectable job. I have not found any significant difference in cutting of the tread between these two models of tyre; my experience of the GP4000s is that it tends to be fine until a spate of punctures near its end of life – my Ultremos are still looking box-new after a few hundred miles.

Sidewall protection: GP4000s II

In contrast to general puncture protection, the GP4000s clearly edges ahead when it comes to the sidewalls. While I’ve even ridden on unsealed surfaces on the GP4000s I would be extremely hesitant about doing so with the Ultremo ZX!

Schwalbe have made a conscious compromise here (you can buy the Ultremo DD if you want heavier sidewall protection at the expense of rolling resistance) and for me, it’s just something to be aware of.

That said, many’s the tyre that has been consigned to the bin after sidewall damage when the tread still had months of life. Your choice!

Schwalbe Ultremo ZX photo

Rolling resistance: tie

There’s no question that Continental hit the ball out of the park with the GP4000s – a recipe that has remained unchanged for years but still performs at the highest level when it comes to the all-important figure of rolling resistance.

Schwalbe make life difficult by recycling and tweaking their model names; historic tests typically show the Ultremo edged out by the GP4000s in equivalent conditions, but this often refers to older versions of the Ultremo (or even previous versions of the Ultremo ZX) so it’s unclear how useful these comparisons really are.

Also be wary of comparisons which use an arbitrary tyre pressure for all tyres (rather than finding the lowest rolling resistance for each model and using that as the basis for comparison). These may seem like small quibbles, but when the difference between “best” and “worst” in this case is under 1W per wheel, in my mind you either need to be hyper picky or decide that other aspects of these tyres are more important.

Styling: Ultremo ZX

I know that beauty is in the eye of the beholder, but the GP4000s is a very plain looking tyre, not that this ever stopped me buying many sets of them! The Ultremo is much more bold aesthetically and, for me, screams performance in a way that the GP4000s doesn’t.

Not that cycling has ever been about looks, right?

Schwalbe Ultremo ZX photo

Conclusion: Ultremo ZX (events), GP4000s II(training)

Although the jury’s still out for me on the longevity of Schwalbe’s Ultremo ZX, it’s hard to ignore Continental’s track record of resilience with the GP4000s.

On the other hand, I love the feel of the Ultremo ZX – the silky ride over rough ground, the confidence in corners, the feeling that you’re giving nothing away.

Schwalbe Ultremo ZX vs GP4000s comparison

In the end it’s a split decision from me: if all my tyres were stolen and I had to start over, I’d be buying the Ultremo ZX for a big day in the saddle but sticking with the GP4000s for high-mileage purposes, like training.

Cop out conclusion? Maybe…. but one thing’s for sure: you can’t lose with either of these great performers!

Looking for a good discount?

At the time of writing, both Chain Reaction and Wiggle have hefty discounts on the GP4000s and Ultremo ZX tyres. Take a look:

Schwalbe Ultremo ZX review

The Schwalbe Ultremo ZX is a superb choice – they roll well, handle beautifully, and they look fantastic.

Trading durability for a wide, supple and fast racing tyre

The Schwalbe Ultremo ZX tyre is not as common as the ubiquitous Continental GP4000s or Michelin Pro, but that situation is slowly changing.

Trading durability for handling and flat out speed, the Ultremo ZX is race-proven and available in a variety of colours and sizes to suit every taste.

For those who have an interest in long distance events the larger Ultremos (25mm and 28mm) are very exciting, although they inevitably won’t last as long as more mundane tyres and you need the clearance to get them on your bike.

The Schwalbe Ultremo ZX racing bike tyre, reviewed

(At the time of writing, Wiggle have a 29% discount while Chain Reaction are doing 33% off the Ultremo ZX).

Width/weight

For a race tyre with puncture protection, the Ultremo comes in at a very respectable 195g (700x23c), less than key rivals such as Continental’s Grand Prix 4000s. (In fact, you can have the 28mm Ultremo ZX for roughly the same weight as the 25mm GP4000s!)

The bead, fabric and rubber make up 160g of this while the V-Guard breaker strip adds 35g. If you’d rather take your chances, Schwalbe manufacture the Ultremo ZLX without any puncture protection at all (unsurprisingly, it weighs 160g).

Schwalbe produce the Ultremo ZX in a variety of sizes, most excitingly 700x25c and 700x28c. The 28mm version weighs basically the same as the 25mm GP4000s (which is only 25g heavier than the 23mm version) removing most of the traditional objection to the use of wider tyres.

The difference between 23mm, 25mm and 28mm may not sound like much, but it actually adds hugely to the volume of the same supple tyre carcass. The 28mm Ultremo ZX has 50% more air in it than a 23mm Continental GP4000s for a rediculously tiny 30g weight penalty.

Not only does this offer extra comfort for long days in the saddle, it increases stability and control on fast descents, rough surfaces and hard maneuvering.

width relative width relative volume
Schwalbe Ultremo ZX 23mm 1x 1x
Schwalbe Ultremo ZX 25mm 1.09x 1.18x
Schwalbe Ultremo ZX 28mm 1.21x 1.48x

For technical reasons, if all else is the equal a wider tyre will also roll faster. All else is very much not equal between a race and touring tyre, but it applies here: the wider casing bulges proportionally less, so the sidewall deflection is slightly closer to a perfect circle (ideal efficiency).

The 25mm size would be expected to gain around 5% over the 23mm for this reason. Those of you who are into longer days on the bike will greatly appreciate the extra comfort combined with extra speed! (Obviously, you need the clearance in your frame and forks…)

continental-gp4000s-road-tyre

Rolling resistance

Precise figures are hard to come by, but the Ultremo ZX is very competitive in terms of rolling resistance – perhaps faster (but certainly not detectably slower) than the GP4000s that are my default choice.

The carcass is 127TPI, as compared with 110TPI on the GP4000s (for one reason or another, Continental add up the three overlapping layers to claim 330TPI, but Schwalbe don’t).

As above, having the option of going wider allows for even faster rolling tyres – the disadvantage of an increased cross-section into the wind shouldn’t worry you unless you’re riding time trials (in which case your bike might not even fit a 23mm tyre, never mind a 28mm one!)

As I’ve written before, both of these tyres are measurably faster than some tubulars (such as the Continental Competition) which should tell you all you need to know about how fast they really are.

The Ultremo will transform a bike fitted with cheap OEM or training tyres.

Comfort

Standard caveat: The Schwalbe Ultremo ZX is a race tyre. It’s not designed to be comfortable in the same way that a touring or utility tyre is (if that’s what you want, I’m afraid you need a different bike!)

I originally got into wider race tyres with Continental’s GP4000s in the 25mm size. I found these excellent on the 1200km Paris-Brest-Paris, where they generally made things more comfortable and provided a bit more control and forgiveness when I was exhausted.

Then I discovered the 28mm Ultremo ZX and realised that I had just enough clearance… I couldn’t resist. The extra efficiency of a wide supple tyre makes a big contribution on long distance events and here the Ultremo really excels.

Compare the volume of the 23mm GP4000s and 28mm Ultremo ZX in this side-by-side:

schwalbe-ultremo-zx-3

 

Grip

The Ultremo ZX is confidence inspiring in mixed or wet conditions thanks to the combination of generous width, supple construction and sophisticated tread. Thanks to Schwalbe’s “Triple Star” compound, the centre of the tyre is more durable while the shoulders are tacky for enhanced grip while cornering.

So far (touch wood!) I haven’t come off on the Ultremo ZX at all, although perhaps I will rapidly come to regret these words… watch this space!

The wide profile of the Ultremo makes it very predictable when leaning in or turning from edge to edge. Interestingly, Schwalbe do manufacture a version of the Ultremo specifically for wet conditions: the Ultremo Aqua. The rubber is so tacky that it comes with a special warning to be vigilant – sharp things are just as good at sticking to this tyre as it is at sticking to the ground!

Flat resistance

Amazingly (again, touch wood!) I haven’t flatted on these yet. However, I ride on roads that are not prone to thorns (and in the tyre track, where glass has generally been pulverised by car tyres)…

The general consensus from those less fortunate than I is that the Ultremo ZX’s sophisticated V-Guard breaker strip is effective at repelling sharp objects, although there are enough disappointed voices to underline that these are racing tyres and not designed to shrug off piles of glass.

In common with all true race tyres the sidewalls are unprotected: vital to minimise rolling resistance, but exposing them to risk of damage compared with heavier and less supple tyres. If you prefer to err on the other side of this compromise you could investigate Schwalbe’s Ultremo DD model, which adds ‘Snake Skin’ sidewall protection at a 45g penalty.

schwalbe-ultremo-zx-2

Durability

Tread thickness is directly linked to rolling resistance. The Ultremo ZX emphasises going fast, so it has relatively little rubber!

As mentioned above, watch the sidewalls. I’m still on my first pair and so far they still look good; as there are no visible wear indicators I shall update this review when they eventually run out of rubber.

I’m hoping to get 2000 miles on the rear tyre which I’ll consider fair innings. At the end of the day they are a consumable item, and we accept the flipside of high performance with eyes open. 🙂

Conclusion

The Schwalbe Ultremo ZX is a superb choice if you’re looking for a racing tyre, and the wide range of sizes available make them especially attractive to those riding longer distance events (or on rougher road surfaces).

They roll well, handle beautifully, have respectable puncture protection and lifespan, and they look fantastic.

schwalbe-ultremo-zx-1

I’m still in the middle of my first set of 28mm Ultremo ZX tyres but they have transformed my ultra-distance experience compared with the 23mm tyres I used to favour. I rode a 208km brevet at the start of the year with almost no miles in my legs, and they seemed to float me over often ragged surfaces, helping me to stay fresh for the big pushes.

At the time of writing, Wiggle have a 29% discount while Chain Reaction are doing 33% off.

Not a tyre to commute on, but awesome for those big days on the road!

Vital Statistics

Note: On a 17mm rim the 700x28c measures 29.66mm

Folding only:

ETRTO (mm) Imperial (“) Pressure (bar) Pressure (psi) Weight (g)
23-406 20×0.9 7-11 100-160 145
23-451 20×0.9 7-11 100-160 160
23-571 650x23c 6-10 85-145 185
23-622 700x23c 6-10 85-145 195
25-622 700x25c 6-9 85-130 215
28-622 700x28c 6-8 85-115 235

 * note that coloured rubber and tubeless options are available in 23-622 / 700x23c only.

Cycling drafting advantage

I recently took the opportunity to record some power numbers on the drafting advantage while cycling in a small group…

Pulling vs sitting in, measured in watts

I recently took the opportunity to record some power numbers on the drafting advantage while cycling in a small group on a brevet in southern Scotland.

Because I already have good power figures for my racer (via PowerTap hub) on the flat in calm conditions, it was a neat contrast to do the same on a real road, with a headwind, as part of a group.

draft-power1

Although the conditions were not controlled (the road was rolling and the wind wasn’t constant – neither was the speed or effort of the group), it was a steady enough effort that I feel confident presenting it here. Average speed for the leg was ~18mph.

The headline figure is that riding at the head of the line cost about 100W more than sitting in (i.e. 250W versus 150W). Drafting is a huge advantage when cycling!

For contrast, riding solo in lab conditions on the flat, I get 16.5mph at 150W and 19.5mph at 250W.

From simple physics, if a climb can be done at 10mph at 150W, 250W means climbing at 16.5mph. A huge difference.

Endurance riders

From these power figures we can calculate the overall saving in energy from a prolonged period of riding co-operatively. An hour at 250W requires more than 900kcal; even riding in a pair (for a total of 30 minutes on, 30 minutes off) reduces this to 720kcal:

draft-power2

Riding in a group of four drops it right down to 630kcal – or expressed another way, compared with a solo rider you will get one hour of progress down the road “free” with every two hours you put in.

The graph above shows the endurance duration of a rider in different scenarios; I chose 2000kcal somewhat arbitrarily because it approximates how much glycogen your body stores in muscles and liver.

“Buy two, get one free” is a huge advantage over long distances. While no cyclist needs to be told that drafting works, it is interesting to see by just how much!

No wonder even a loose group can make real headway…

An aside on recumbents

I haven’t yet had the chance to collect decent data on pulling versus sitting in a group on a recumbent.

However, I do find it interesting that when I tested the RaptoBike midracer against my road bike I found approximately a 100W aero advantage at these speeds (150W giving 19.4mph recumbent, where 250W gave 19.6mph upright).

This ties in nicely with my rule of thumb that riding a recumbent is like having a group to draft behind all the time…