Are all Watts created equal?
I've been pondering a question that I can't seem to wrap my head around. Maybe it's because I think about it while I'm on the trainer and relatively hypoxic, but hopefully, someone can explain this to me:
I understand that ability to ride fast is dependent on Watts/kg outside because of variables. So, wind, coefficient of drag, rolling resistance all play a role, and if you are bigger, these variables are also bigger. Okay, I get that. But on a trainer, aren't Watts just Watts? What I mean is that there is no wind; there is no drag; and with your frame suspended by a trainer, rolling resistance is constant. So, if one person is pushing 300 Watts, and the other is pushing 200 Watts, as long as the amount of resistance (that is adjusted) is the same, will the one pushing 300 go faster than the one pushing 200, regardless of their size?
I know that speed on a trainer is not an important measure, but I am just curious about this.
Comments
I suppose if both people were on identical trainers, then yes, 300w will read "faster" than 200w.
Speed on a trainer is only relevant to exercise on that trainer. If you don't have power, then speed can be used as a surrogate for effort or power, and distance travelled will represent total effort for the workout. This usefulness falls apart if the trainer in question has a variable resistance curve... whether a manual feature or due to temperature.
I had a fluid/mag Performance trainer a few years ago. The magnetic part had 5 resistance settings, and the fluid part got harder as it heated up, which I don't think was intended as a feature.
-Joe
[Edit for typo]
Good input!
On a side note, I burnt the crap out of my hand the other day ago when I went to move my trainer after riding. I think you can fry an egg on that mag. Be careful!
Yes - more watts will equal more speed generally. Often true even outside. Unless you are talking about a crazy hill climb where w/kg are a bigger factor which changes things a bit. On a flatish course someone pushing 300 watts is always going to be faster than someone pushing 200. Just works out that way. A lil peep with 4 w/kg can get crushed by a bigger dude with 3.5 w/kg. All of this presupposes that a watt measured on the PM's are pretty close, which is only kinda sorta true. Comparing yourself to others by comparing wattage numbers is not a very useful exercise. Comparing yourself to others by looking at race results or by how long they have to wait for you or you for them is much better.
Yes! That's really what matters, at least to me. In addition to all the above, of course we've seen "lower wattage" individuals succeed by mazimizing aero postion and cycling efficiency - low VI trumps higher VI, which won't play out on a trainer at all.
But even within that construct, the actual resistance will depend on the tire pressure, tension of the clamp/flywheel/whatever.
I once saw a guy who has rollers do a watts vs. speed test for himself with the only variable being tire pressure...and higher tire pressure meant a lot fewer watts to go a certain "speed". (this was important for these local "roller races", which are of course won by the big guys because it's all about making the trainer go 2 miles with no wind resistance on the rider per se).