I did a race back in May (The Rookie for you Texans) with a 11.1-mile bike. I rode with an average power of 208 and a normalized of 215. That lead to a 20.7 mph average.
I did another race at the same site today with an extra leg on it that made the bike course 14.8. A test of n=1 doesn’t mean much, but my equipment was exactly the same. Wind conditions were very similar and may have been actually calmer today. The additional road on the route was of similar quality to the rest. The extra distance didn’t increase the number of turns or add a higher proportion of hills.
So here’s what I don’t understand: today’s ride was at an average of 232 with a normalized power of 241. That’s an 11.5% increase in power. My average speed? 21.5…an increase of .8 mph, less than 4%. I know, I know…wind resistance is exponential. An 11.5% increase in power is not going to turn into an 11.5% increase in speed. But 4% at this low a speed seems a bit small.
Maybe the conditions, while seeming to be similar, were different enough to account for the limited gain, right? Except that *every *person I’ve looked at that did both races, both at the front of the pack and near me (13.7th percentile for this race) increased their speed between the two races. Of the 6 in the top 20 that did both races, there was an average increase of 1.5 mph. Back by me, I looked at the closest 10 around me that did both races. Their average increase was 1.16 mph. There was 1 person that increased only .6 mph, but the other 9 all increased *more *than I did. It seems a bit of a stretch to believe that all of these people increased their power output even more than I did since May.
I’m thrilled with the increase in power. That’s a big jump over the course of the season and I don’t think I’m even close to my potential. But I’m starting to wonder if it’s something with my wheels, my frame, my position (which I think is pretty good), etc. I’m even wondering if my PT is just drifting upwards and I’m not really getting more powerful. I had started to notice this on other training rides, i.e. more power but no gain in speed, but wrote it off to conditions on that particular day. I’m not too concerned about the drive train, since I’m obviously getting the power to the hub. Could there be increased friction in the hub? Any other thoughts on my long rant?
I did a race back in May (The Rookie for you Texans) with a 11.1-mile bike. I rode with an average power of 208 and a normalized of 215. That lead to a 20.7 mph average.
I did another race at the same site today with an extra leg on it that made the bike course 14.8. A test of n=1 doesn’t mean much, but my equipment was exactly the same. Wind conditions were very similar and may have been actually calmer today. The additional road on the route was of similar quality to the rest. The extra distance didn’t increase the number of turns or add a higher proportion of hills.
So here’s what I don’t understand: today’s ride was at an average of 232 with a normalized power of 241. That’s an 11.5% increase in power. My average speed? 21.5…an increase of .8 mph, less than 4%. I know, I know…wind resistance is exponential. An 11.5% increase in power is not going to turn into an 11.5% increase in speed. But 4% at this low a speed seems a bit small.
Maybe the conditions, while seeming to be similar, were different enough to account for the limited gain, right? Except that *every *person I’ve looked at that did both races, both at the front of the pack and near me (13.7th percentile for this race) increased their speed between the two races. Of the 6 in the top 20 that did both races, there was an average increase of 1.5 mph. Back by me, I looked at the closest 10 around me that did both races. Their average increase was 1.16 mph. There was 1 person that increased only .6 mph, but the other 9 all increased *more *than I did. It seems a bit of a stretch to believe that all of these people increased their power output even more than I did since May.
I’m thrilled with the increase in power. That’s a big jump over the course of the season and I don’t think I’m even close to my potential. But I’m starting to wonder if it’s something with my wheels, my frame, my position (which I think is pretty good), etc. I’m even wondering if my PT is just drifting upwards and I’m not really getting more powerful. I had started to notice this on other training rides, i.e. more power but no gain in speed, but wrote it off to conditions on that particular day. I’m not too concerned about the drive train, since I’m obviously getting the power to the hub. Could there be increased friction in the hub? Any other thoughts on my long rant?
I’d say the powermeter wasn’t zero’d out the same each time.
i don’t have an exact % (and it is a sliding scale) but it takes a crazy amount of power to increase speed. And it gets worse and worse the faster you go (large increase in power to make a small gain in speed)
but congrats on the gains - we all like to see improvement!
First I’d say you’ve got lousy aerodynamics if you got those speeds with those powers. I can get 25 mph on 240-250 W in full aero gear. That said, I don’t see anything unreasonable with the increase in power for the stated increase in speed. You only averaged 24 watts more (normalized is meaningless here), and with that I’d expect no more than a 1 mph increase.
Speed and power are more than exponential, they are almost to the cube. Using the cube relationship, a 4% increase in speed would require about a 12% increase in power. Seems like everything is pretty much right on. If you need to go to analyticcycling.com and check out what they say.
It takes big increases in power to see reasonable increases in speed. It takes huge increases in power to see big increases in speed.
Speed and power are more than exponential, they are almost to the cube.
Uhh, speed and power aren’t “more than exponential.” They are exponentially related. Power is proportional to v_ground*v_true^2. Doesn’t matter whether v_ground=v_true or not, it’s still an exponential relationship, not “more than exponential.”
Speed and power are more than exponential, they are almost to the cube.
Uhh, speed and power aren’t “more than exponential.” They are exponentially related. Power is proportional to v_ground*v_true^2. Doesn’t matter whether v_ground=v_true or not, it’s still an exponential relationship, not “more than exponential.”
Speed and power are more than exponential, they are almost to the cube.
Uhh, speed and power aren’t “more than exponential.” They are exponentially related. Power is proportional to v_ground*v_true^2. Doesn’t matter whether v_ground=v_true or not, it’s still an exponential relationship, not “more than exponential.”
You and Frank need to take the same class.
Speed and power **are more than exponential, they are almost to the cube. **Using the cube relationship, a 4% increase in speed would require about a 12% increase in power. Seems like everything is pretty much right on. If you need to go to analyticcycling.com and check out what they say.
LMAO, a 3rd grade kid probably knows math better than you!!! How did you engineer those cranks ???
What did your computer read on the mileage? If you are comparing your computer to what run-far calculated…it could be that one of the distances is off…either The Rookie or JGT. I haven’t really thought this through completely and don’t use a computer for racing, but the bike may have been a tad shorter than 14.8 miles…which would explain the faster times in respect to the Rookie. Of course, if you used run-fars #s then yours should increase the same %age with everyone else’s.
I wouldn’t loose too much sleep over it. If you went up the hills slightly less aero today than you did at The Rookie, then your power would have had to increase to maintain the same speed. It would have had to increase even more to go faster. As long as you are getting faster and the watts are improving…that’s what everyone wants to see…except your competitors.
a powertap does not zero out automatically - check the manual - (unless you have a crazy sci fi one I haven’t seen)
Hmmm…then why in setup screen 3 of my PT Pro head unit is there a choice for “torque autozero yes/no”?
“Speed and power are more than exponential, they are
almost to the cube.”
What do you mean by that?
Given that air density, wind condition, and area of the object are the same; aerodynamic drag would increase with velocity^2.
(smiley face)