1 minute: upright vs MetaBike power

Comparing power output on the MetaBike versus upright DF bike on a one minute max effort hill climb…

Following my recent PowerTap test of the RaptoBike Midracer / DF racer, I said I hadn’t bothered to record a maximal effort on both bikes because the figure would reflect a lot of inequalities:

how much have I been riding either type of bike?
are the tyres comparable?
how efficient are the particular drivetrains (is one chain dirty and the other clean?)
what’s going on with frame flex?
etc. etc.

However, more than one person in various forum discussions said I should record maximal uphill efforts on both platforms to provide some backdrop, despite the fact that it wouldn’t isolate a particular factor.

Edinburgh’s Observatory Rd: short but sweet…

So, against my better judgement 😉 I ran a head-to-head between the MetaBike I had out on trial (known to be one of the stiffer and better climbing recumbents) and my all-steel commuter bike. I chose the commuter because the all-up weights of both bikes come very close – possibly the DF is a little heavier in fact…
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Powertap: convert watts to calories burned

Calculating calories (kcal) consumption for given wattages using a cycling power meter, such as a PowerTap.

Calculating a hard baseline for energy expenditure

PowerTap. After the immediate thrill of “how many watts can I do?” (answer: disappointingly few!), I moved on to the next most obvious question: “how fast will my bike(s) go for a given wattage?”

However, there’s another side to measuring power output which I hadn’t really considered until some time after I built up my PowerTap. You actually know how much energy you put into the road over the course of a ride (or part of a ride).

Turning watts into calories

If you know duration and average power you already have energy, it’s just not expressed in good old-fashioned calories. It turns out there’s a suprisingly simple formula to turn the wattage from a power meter into kcal though:

energy (kcal) = avg power (W) X duration (hours) X 3.6

As with so many surprisingly straightforward looking formulae, there are assumptions built into the constant.

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Power Test: RaptoBike Midracer

A 100W advantage? Testing the efficiency of the RaptoBike Midracer recumbent versus a drop-bar racing bike…

Measuring aerodynamics / rolling resistance

Not measuring drive losses or biomechanical efficiency

In this article I use (PowerTap hub measurements in loosely controlled outdoor conditions to provide an insight into the performance of the RaptoBike Lowracer. Please note: the test protocol is discussed frankly at the end of the article.

The Bikes

In the blue corner:

My Planet X Superlight Team road bike, a pretty standard sort of roadie creation, weighing in at around 8kg with SRAM Rival. If I had a fitting, I suspect the bars would come back a little, as I’m quite stretched out (although that should favour the bike’s performance in these sorts of tests).

Tyres: Continental GP4000s rear, Vittoria Rubino Pro3 front

In the red corner:

The RaptoBike Midracer, a FWD recumbent that is aimed towards the faster end of the all-round market (it’s not as much of a ‘racer’ on the recumbent spectrum as my DF is, for instance it can carry luggage). The Midracer weighs in at around 13kg.

Tyres: Continental Gatorskin 25mm rear, Continental GP4000s front

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