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…
Continue reading “1 minute: upright vs MetaBike power”
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.
Continue reading “Powertap: convert watts to calories burned”
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.
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
Continue reading “Power Test: RaptoBike Midracer”