Raxel: iBike should be interesting... It's not as good as a real power meter, but it may be the only option for a 20" wheeled bike.

A correction to your post, though.... Small wheels have more rolling resistance; see http://www.users.globalnet.co.uk/~hadland/rolrec10a.pdf for details. I believe the issue is that the tires, and therefore the contact patch, is wider; the shape may also have an effect. Smaller wheels are faster because, even with wider tires, they are aerodynamically superior to 26" / 700c.



I'm afraid you are incorrect. The power meter will quantify exactly how much power the bike needs in order to, for example, increase speed.

If Bike X moves at 22mph when you apply 200 watts to the pedals, and Bike Y moves at 23mph @ 200 watts, we can objectively say "Bike X is more efficient / performs better / faster."

Bike weight will NOT increase the rider's mechanical inefficiencies. They're two different systems in that respect. Those mechanical inefficiencies are altered by factors like: Muscle soreness, low blood glycogen levels, injuries, a rider position that impedes or aids muscle function, rider fitness, aerobic vs anaerobic efforts.

The power meter quantifies how much extra that 5 pounds makes you work; and everything indicates that by almost any measure, it's a very small amount. Staephj1 and Invisiblehand pretty much get it, by the way; I'm only disagreeing with them about the situations where this small amount does become critical.


I agree there is a big difference between racers and non-racers, but not the one you are describing. In terms of power, a trained cyclist will be able to sustain a much higher power output for longer periods of time and in a more efficient manner, but that's really about it.

A racer will definitely want to be as efficient as possible. If you need to work twice as hard as your competitor in order to maintain the same speeds, you will lose.


OK, let's say that your body is generating 620 watts in total, you lose 70% to mechanical losses, that leaves 186 watts on the pedals. To increase by 1 watt to 187w, you'd have to generate, oh, 624 watts instead. That's a 0.6% increase.

By the way, maintaining that increase means you'll burn an extra 1 or 2 calories per hour. Wow. That's huge!

You sure you want to pursue this line of argument?


It isn't. So it doesn't.

The only way that 1 watt can have a huge effect on your efforts is if you are already at LT when you generate 200 watts, and that extra watt makes you go anaerobic. At that point, your body becomes much less efficient, you burn lots of fuel, and it gets harder to recover from your efforts. This can definitely happen -- I've even referenced this scenario a couple of times re: club rides -- but you have to be right on the line the entire time, which is not exactly a common scenario.


This is absolutely incorrect.

A typical / non-trained rider will put out roughly 150-200 watts. An amateur racer will be in the 200-300 range. A pro is 300-400 or more. And yes, we are talking about consistent, multi-hour outputs here.

And again... Just going into the drops, instead of riding on the top of your bars, saves you about 40 watts. If you lower your handlebars by 1/4" you'll likely get a bigger performance boost than by dropping 5 pounds.

1 watt is the difference between "me on Tuesday" and "me on Wednesday." Seriously, in a non-competitive context it is negligible.