I think perhaps we agree on most of the specifics and disagree mostly on the significance of their effect. I am sure that significance is greater or lesser depending on who you ride with, how you ride, and where you ride.
Originally Posted by
Bacciagalupe
• If you're getting dropped on a club ride, it's not because you have an extra 5 pounds on the bike. It's the engine. You know it, I know it, and everyone else on the ride knows it.
Actually I am not getting dropped, but I would be on some rides if I was carrying a couple extra pounds on the wheels and tires. I haven't ridden club rides over major passes like we toured on in the Rockies or Cascades, but I bet 5 pounds could easily make the difference under those situations too. I do have to work harder on local group rides when on a heavier bike especially if the extra weight is in the wheels and tires. No I don't feel it on the flat straight sections, but I do on the climbs and the accelerations out of the corners.
Originally Posted by
Bacciagalupe
If 38 seconds out of 20 minutes is critical, it's not because it's a large amount of time, it's because you happen to be in one of the situations where small changes in performance are significant (let alone actually measured).
Absolutely,
IF you ride alone and are not riding for a measured performance, but there are real life non-racing situations where that is significant.
On tour riding with a small group on the Trans America, we adjusted weight by a few pounds a number of times. These adjustments were sometimes done by sending stuff home and sometimes by shifting community gear between us. I have no doubt whatsoever that these changes made the difference in whether a rider kept up or not either in terrain where there were lots of short ups and downs or areas where there were long multi-mile multi-thousand foot climbs. If fact the difference might have been the difference between finishing the 4200+ mile ride and giving up and going home.
On two recent long rides in similar terrain I rode with my daughter. On one ride we were both on our touring bikes and on the other I rode my road bike. The difference in aerodynamic drag is an obvious factor that favored the road bike. Also rolling resistance is a small but not insignificant factor since she is running 28 mm tires at 100 psi. When we were both on 30 pound bikes she kicked my @ss on the climbs. When I was on a 20 pound bike, she dropped back a bit on each climb and had to catch up. Since the difference was on the climbs I think it is reasonable to say the the weight was the major factor.
Originally Posted by
Bacciagalupe
Last but not least... I'm no longer accepting the assumption that "added weight produces a significant performance loss on the flats" without some kind of proof.
That is pretty funny; since I didn't know you were before
If you want proof go get it yourself. It is a well accepted fact that weight has a significant effect when accelerating, particularly if the weight is in the wheels. So it is not
whether it makes a difference, but
how much. I do agree that weight matters very little for flat roads and steady speeds. It quickly becomes more important as accelerations become more frequent and/or faster. So for the case where you are in no hurry to accelerate out of corners and are not climbing, within reason weight is a very minimal factor.
Since I ride with riders who are usually 30-40 years my junior and pretty aggressive, accelerations are quick and weight especially in the wheels is not insignificant. For other riding it may be.