Fast 700c recumbents – power test

A side-by-side comparison of the speed of the Schlitter Encore, Optima High Baron and M5 Carbon Highracer

Side by side M5 CHR, Schlitter Encore, Optima High Baron

I’ve been riding a review copy of the Schlitter Encore recently, along with the Optima High Baron which carried me to a 7th place finish at this year’s Tour o’ the Borders.

To complete a nice side-by-side performance test I borrowed the demo M5 Carbon Highracer from Laid Back Bikes in Edinburgh – brief side by side comparison here.

The test protocol was simple – go to the promenade and ride up and down beside the sea (nice and flat) holding a given power for the whole of a lap without touching the brakes, then see how fast I went on each bike.

I varied as little as possible between the bikes, including using the same wheels (where possible) and power meter etc. I also tried for the calmest conditions in terms of wind, although naturally in Edinburgh it was impossible to find a calm day.

Just a note – it would be much better to perform virtual elevation calculations for each bike. I think there is a good bit of error in the testing described below, but I just can’t find a convenient route that doesn’t require use of the brakes (compounded by living in the world’s windiest place… it’s a hassle!).

Until someone produces a proper calculation, we make do with cruising beside the sea in the sunshine… I suggest that these results are taken as indicative only, though for what it’s worth I do feel that the ordering matches my gut feel of how each bike rides.

Headline results

It turned out to be a little tricky to get exactly the target wattage for each run, so first of all here is a graph of speed per watt for each bike (all laps of both directions averaged) to give a comparable ranking of “bang for your buck”.

overall-speed

To add extra context, I’ve plotted previous data from a head-to-head comparison between my DF racer and the Raptobike Midracer which was not captured at the prom (and obviously on a different day, three years ago!)

As you would expect, while you go faster at 250W than 200W, higher power gives diminishing returns due to the exponential increase in wind resistance, so the high power runs (plotted in red) show less speed per watt than the lower power runs (plotted in blue).

The ordering hopefully won’t come as much of a surprise, with my DF racer languishing at the bottom of the pile. The M5 Carbon Highracer was fastest, followed closely by the Optima High Baron, with the Schlitter Encore coming in just behind. Probably the most interesting thing about this for me was how little separated each bike:

rawdata

The next chart breaks down the laps by direction. You can see variation between the bikes that is only really attributable to varying wind speed as the test went on (the Encore does better downwind and worse upwind than you might expect, presumably because the wind speed / direction wasn’t steady). That said, if the Encore was less aerodynamic you would expect to see it hurting more on the upwind laps than the downwind ones (the big open cockpit riding in the airstream etc?):

wind direction

Assorted caveats

TL;DR – the CHR is a shop demo and not optimised for naked speed, the Encore is a new-to-me review bike and I haven’t spent a lot of time tweaking it, while the High Baron has been mine for three years and I’m very comfortable on it!

Here are a few confounding factors to consider in detail:

– I’m not tall enough to ride the CHR with my power chainset (170mm) so I was using a PowerTap wheel and plain 155mm cranks instead. The PowerTap reads 1-2W higher based on testing conducted with both meters fitted on a turbo trainer (so this slightly disadvantages the CHR, by about half of one percent – down in the noise of wind gusts unfortunately).
– I used the same 32 spoke 3-cross Archetype wheelset with 28mm Schwalbe Ultremo tyres on the Encore and High Baron, but the M5 CHR doesn’t have enough clearance, so I had to use the provided Shimano R500 front with Schwalbe Durano Plus tyres (faster wheels but slower tyres on the CHR).
– The Archetype wheelset has a Shutter Precision hub dynamo on the front, the R500 does not. (The lights were off, but there is still a small amount of extra friction, amounting to the equivalent of a couple of feet per mile extra gradient).
– I used a Radical Aero seatbag on all three bikes, but on the CHR I used the stock bag from Laid-Back-Bikes which still has the fabric bottle holder on the side – I cut this off on my own Aero seatbag.
– I didn’t have a mirror fitted on the Baron or Encore but had a small mirror fitted on the CHR, although I turned it parallel to the wind for the test.
– Both the M5 CHR and High Baron are running dropped chains, but the CHR has a bit of chain tube to make it more useful as a shop demo, which will add some (an unknown amount of) friction to further disadvantage the CHR.

Seat Angle

Refer to the posts linked in the first two paragraphs for photos of all three bikes (I’m afraid I’m still working on formal reviews of the M5 CHR and Encore, so don’t have comparable shots of them to stick in a rollover).

My High Baron is as reclined as the frame will allow, but the M5 CHR can go flatter with a bit of modification to fit a lower seat pillar, as can the Encore (to a lesser extent – the seat back was closer to the max recline without doing something drastic).

If you’re willing to ride with a really low angle seat you can certainly get more speed out of these two bikes than I’ve demonstrated, whereas the High Baron is probably about as good as anyone is going to get it. (M5 have the world hour record on a similar design where the rider lies flat on his back!). Of course, you may not want to ride around flat on your back with special measures to avoid looking under your bars to see the road ahead. There’s a reason that almost all bikes are sold with a seat at these angles or above…

You could also put a tiller on an Encore very easily, and get your arms tucked up out of the way (while the J-bars are one of the big selling points of this design, you are sticking a couple of feet of pipe into the airstream above your knees, and also your arms are spread wider). But maybe you’ll decide that a nice handling bike which is pretty fast is fast enough! There’s more to life than speed at any cost…

Weight

Finally, I didn’t attempt to equalise the weight of the bikes, since I’m not interested in purely their aerodynamics, rather the “complete package”, and on the flat the difference should be minimal anyway. However, note that the M5 CHR and Schlitter Encore both weighed in at a little over 10kg (22lbs ish) whereas my High Baron weighs more like 11.5 – 12kg in current form.

All could be lightened but the High Baron will always be heavier. This, plus frame and cockpit stiffness, would show up in a bigger way on an actual cycle ride with hills, dropping the High Baron down the ranking.

I believe (subject to a full dismantling and the weighing of individual parts) that the Encore can be made lighter than the M5 CHR.

Anyway… hopefully this is of interest, and as ever, feel free to drop a comment below…

Randonneuring: recumbent efficiency

Measuring the difference in wattage between equivalent performances on a 400km brevet, recumbent vs upright

It’s easier lying down… but not by as much as you might think.

I’ve written before about the power advantage my High Baron recumbent enjoys over my normal road bike, but only in the context of a ~20 mile commute to work. I found that on average each recumbent mile cost 36.2kCal, versus 47.3kCal for each upright mile.

If that held out for a long brevet, it would be a significant advantage to the recumbent platform (a 3800kCal saving on a 600km brevet, for instance). But how comparable is my commute, an hour pretty much as fast as I can go, with an all-day or even a multi-day effort?

Now that power meters are getting a bit more commonplace, it’s easier to answer this question without going to heroic solo efforts in the name of science.

recumbent_vs_road_bike

I rode the National 400 out of Dingwall this year, 256 miles (or ~400km! 😉 ) with around 14,000 feet (4270m) of ascent. Rather than ride the National 400 route twice on different bikes, instead I’m going to compare my power with another rider who did the course on the same day. The advantage of this is that weather etc. is exactly matched, but the danger is that energy use is proportional to weight (especially going uphill) and also the speed you travel at, and if these aren’t controlled, you might not get such useful data. In particular, if riders are drafting you may as well call the whole thing off!

Fortunately in this case our speeds were fairly closely matched and neither was drafting at all. I chose four segments between controls in the middle of the ride for comparison, as our average moving speeds were 16.496mph (recumbent) vs 16.507mph (upright), probably close enough! The total distance was 137.6 miles, the ascent 7,500 feet and the route profile between each control is as follows:

seg1

seg2

seg3

seg4

As you can see, it wasn’t the hilliest of routes, but there was a respectable amount of climbing. The first segment had a bit of a headwind, the others a tailwind. See the overall map view:

map

Before looking at energy used, it will be useful to calculate the respective weights. I looked at a fairly steep hill (7-8%) to broadly isolate the weight component. In this case the recumbent sustained 7.7mph for 247W, while the upright got 8mph for 239W. Knowing fairly accurately the all-up weight of one rider, we can crudely solve for the all-up weight of the other. In this case my own weight (inclusive of bike, spare clothes, tools, 2L of water) works out at roughly 6.5kg heavier than the rider on the upright.

Ideally we would have had a set of scales at the arrivée, but what can you do! This will be useful in a moment as a caveat on the overall comparison…

Knowing duration and average power we can calculate total energy consumption across each platform. See the table below for some of the detail:

Notwithstanding the weight penalty, the recumbent rider travelled at the same speed using 8.5% less energy.

Overall the recumbent used 5240kJ (36.9kJ per mile) whereas the upright used 5715kJ (40.27kJ per mile). The calculated efficiency for the recumbent is interestingly close to the 36.2kJ from my previous comparison, but the DF efficiency is much better than my commute’s 47.3kJ per mile. Quite a different result overall to the 24.5% saving on my commute – I suppose this highlights the difference between riding at 15mph and 20mph, which is my average speed for a commute, in terms of the recumbent’s aero advantage.

(I’ll just take this opportunity to point out that my recumbent, pictured below, didn’t weigh 6.5kg more than the upright, although it contributes a couple of kilos for sure. If I’m honest, it’s probably mostly the rider who was a bit more portly!)

highbaronchainline

When you break it down a bit, as expected the relatively flat stage over the watershed from Lairg to Achfary (roughly 30 miles, 800 feet of climbing, into the wind) shows a dramatically better result for the recumbent than the other stages (hillier, no headwind). I was travelling at 18.4mph while the upright rider made 16.7mph – yet I used just 885kJ to get between controls, compared to 1091kJ for the upright – an increase of 23% in energy spent AND a reduction in 1.7mph average speed…

Anyway, that’s quite enough geeking out on power data for one day. Hopefully this is thought-provoking – please drop a comment below if you have any feedback!

Schlitter Encore preview

Early thoughts on the excellent Schlitter Encore – a custom sized, aggressively priced carbon highracer

Aggressively priced custom-sized carbon highracer

Last weekend I got out on the Schlitter Encore for my first long ride – a hilly 55 miles around the Tour o’ the Borders short route with David Gardiner of Laid Back Bikes (who took these pictures).

The company kindly sent me a frameset to build up and review, so I’m now using it to put in the miles before coming to a final verdict. However, here are some early impressions…

encore-preview1

First, the Encore is scandalously light. Even with spare parts from my garage collection the complete bike (including pedals and seat pad) weighs in at ~10kg, so it could easily be lighter if you invest in the finishing kit. As it is, I don’t think you will find a lighter frameset off the peg at anything like this price. A frameset will set you back a little over 1900EUR.

It’s also impressively stiff – possibly the stiffest recumbent I’ve ridden since my RaptoBike lowracer. That said, the super long handlebar setup does bend a lot when you haul on it, which is giving me some caution trying to rank the bike absolutely (I’m not sure how I would rank it against the M5 CHR for stiffness, for instance).

The frame does not have a sliding boom – instead the factory glue the BB ‘cap’ onto the end of the frame once cut to length. There is a little adjustment in the seat clamp to allow a range of riders to fit comfortably, so it’s not going to be impossible to sell on, but someone with the original owner’s dimensions is always going to be in the sweet spot.

And what a sweet spot it is!

encore-preview3

It’s hard to overstate how well the Encore handles in a general sense. It’s night and day compared to the poor experience I had on the Bacchetta Corsa, quite apart from the issue of getting your feet down (see below). The bike is perfectly balanced which means you can take full advantage of the short wheelbase without it feeling too unstable or twitchy.

Although there are other reasons to choose one over the other, I would rank the Encore above the Metabike (carbon and aluminium versions) in the handling stakes too. You can see from the photos that these are challenging roads, but I was able to descend almost as fast on the Encore as I did on my High Baron next time out. The MetaBike never quite made it for me on limited review mileage. That’s extremely impressive when you consider how much experience I have on my own bike!

encore-preview2

Although the seat is still high compared to the High Baron (or especially the M5 CHR) it’s fine for me to touch down when stationary without having to move on the seat. Since I have a relatively short x-seam, this makes the bike even more attractive compared to the traditional stick bike models.

One of the most visible innovations on the bike are the handlebars – “J-bars” which try to combine the open cockpit riding position with the forward visibility of a tiller setup. I’ve never got on with open cockpits in general, but I will say that the bars on the Encore are surprisingly comfortable once you get them adjusted right. The forward visibility really is excellent and for that reason alone I think they’re a no brainer.

encore-preview4

Unfortunately I’ve already had two incidents where the bar hit my thigh. One forced me to abandon the steep (> 20%) climb up Talla because I just couldn’t keep my legs inside the bars while putting out full power to keep the bike moving. The second was a high speed sweeping turn onto a shared path where I had to basically slam my inside foot into the ground and grind on my cleat to stay upright after entering the corner a bit too fast and sharply. I should add that in normal riding (including a few rush hour commutes) the Encore has given me no trouble at all. I’m probably just too used to the ease of the tiller setup.

I don’t feel the Encore is quite as aerodynamic as the High Baron for any given seat angle, and indeed my power meter testing shows a small advantage to the Optima (to the tune of ~0.5mph at 200W) on the flat. I used the same wheelset for this comparison and think it is broadly valid, although more research is needed!

Anyway, enough rambling for now. It’s time to go for a ride!

Hit the comments section if you have any questions or feedback…

encore-preview5