CAMPYBOB said:
SIC, you CAN'T feel the difference in spin-up going from a training sew-up to a racing one makes???
Seriously.
Difference is there, but tiny. It takes bugger all effort to spin a road wheel, from the heaviest to the lightest. Hang your bike in a stand, and give it a try. Spin your wheels. Seeing as your legs should be monumentally stronger than your arms, it should become clear how little effort it takes to actually spin up a wheel.
Now, 4.8lb isn't a small amount of weight for me. For a rider of 200lb, it is still a fair increase, 2.4%. For me, it is an increase of 3.3%. Add two of those and that's 6.6% (body weight only). Total system weight it's a 5.9% increase. That is a ridiculous idea, once again.
Now, When I commute, I do it with an extra 20lb strapped to my bike. Yeah, it takes more to accelerate, that is logical, but once you are moving, it stays moving. But 20lb is much more than 1lb.
Changing the system weight by 1% would require a weight drop of 760g for me. That is massive if you only have a few parts that you want to change. Now, ignoring the massive number of variables kicking around the real world, if that did lead to an extra 1% acceleration increase putting out the same power (wind resistance says it won't. Wind resistance doesn't increase linearly) and lets just say we are going from the line, so from 0 to, say, 40km/h. A 1% increase takes me to a whopping 40.4km/h. I think my opponents may just be able to hang in my draft at that whopping speed. Accelerating out of a corner from 30 to 40 will only bring a 0.1km/h boost, seeing as the 30km/h is irrevlevant, and it is only a 10km/h acceleration.
0.1 km/h is much less than the difference between a good and bad day, or sprint tactics. That is a 1% drop. Now consider a 200g drop. That is a bit more than a quarter of that. IOW, bugger all.
Bringing in your real world argument, the increase in acceleration shuold be less than that because you are assumedly in the wind if you aren't trying to stick second wheel. As everyone knows, drag increases by the square of velocity. Double the speed, you get twice as much drag. Also, to double the speed, it takes eight times as much power (cube of the velocity) so as you go faster, it takes much more power, so you better be putting out more power, otherwise that 1% gain will start to diminish. Also, assuming you are in a crit, if you are accelerating like this, your opponents are probably on your wheel, taking advantage of your draft, not using as much power or energy.
Now, as to the hilly century, if you are operating under a threshold power range for all powers, there is no reason why you would feel much different carrying an extra 200g, except fitness. I have actually logged faster times up a local climb (3km, averages somewhere around 8.4%. First half averages 12%, hitting 15) using my heavier training gear during a long ride (110km, long for me) than light gear.
as i said, 200g remains 200g.