Originally Posted by
RChung
I care about whether they read in chicken-power because in order to test their accuracy, I measure the difference in reported power when adding a known mass, or climbing a known height, at different known speeds. It's a lot easier to do that in watts than in chicken-power.
Pacing can actually be important (but it's more about the distribution of work than raw power). One of the earliest things I learned from using power is that my previous pacing using RPE was way off. Having accurate power data (not just consistent) helped me to learn when to trust my RPE and when not to, so I learned how to "re-calibrate" RPE. That's especially important near threshold, so having accuracy near threshold was important to me.
My threshold power is defined using the same "chicken-power units" as I ride with. So in that sense it doesn't really matter. But as it happens I don't think my PMs are far off measuring in actual Watts. So it's all good for my simple usage and pretty effective. I found the same with RPE. I tended to ride too hard when I was fresh and full of adrenaline. Now I pace long climbs much better and usually better than my friends who ride without power. I'm now pretty good at guessing what power I'm riding with too. I just have a single-sided Specialized/4iiii crank sensor on my road bike and an Elite OTS on my trainer. I've been impressed with both their consistency and agreement. The Elite consistently reads about 3-4% lower at my threshold, which is to be expected with drivetrain losses. I have compared them at steady power levels from 100W through to 350W and they are within that same 3-4% window, perhaps a little higher at very low wattage, but that doesn't bother me. I'm about to move onto a Kickr Bike for my indoor training this winter, so will be interesting to see how that compares on power measurement, but I'm not expecting to see a big difference.