Which pound weighs more?

Quoted post said:

Originally posted by JOT
Is there any difference whether I have a bike that weights 2 pounds less or if I lose 2 pounds? Very light bikes always seem to fly, but losing weight doesn't have same effect, even with good wheels, on a weightier bike. Opinions and/or physics?

If "difference" means the speed in climbing hills, or the rolling resistance, it shouldn't make any difference. The power needed is a function of the total weight of the body and bike together.

If you're talking about rotating weight, eg, wheels, there would be an extra advantage gained in acceleration by saving weight off the wheels. This is limited of course....you can only lose a pound or so by going to the lightest wheels vs conventional.

As a personal example, I got more serious about riding this past year and lost 45 pounds. When I got to my goal weight, I bought a bike that's 4 lbs lighter than my old one. I certainly can tell the difference in bodyweight on the hills, but have to really reach to say the 4 lbs lighter bike is a huge deal now. It does feel faster and smoother of course, which is a boost in itself.

Dan

Quoted post said:

Originally posted by dhk


As a personal example, I got more serious about riding this past year and lost 45 pounds. When I got to my goal weight, I bought a bike that's 4 lbs lighter than my old one. I certainly can tell the difference in bodyweight on the hills, but have to really reach to say the 4 lbs lighter bike is a huge deal now. It does feel faster and smoother of course, which is a boost in itself.

Dan

Yeah,my motor is alot more important than the difference between my light and heavy bikes. Wheel and trie weight seems to make singificant difference.

You feel the decreased bike weight in your hands, feet, arms, and legs. You feel the decreased body weight in your heart and lungs.

Just my completely unscientific opinion there, people; but those of us who've lost weight both on the body and on the bike know the feeling.

OK, guess if the bike is a little more responsive to inputs it should be noticeable where you hold on. Only rode the new one once before leaving for holidays, so I'm looking forward to more detailed comparisons next week.

Concerning the wheels, I've got a short, steep hill I ride down every day, hitting 35-40 mph on the old bike (MA-3 rims, 32 spokes) depending on my tuck and winds. The new bike has the Circuit Comps. I plan to switch front wheels out, see if I can notice the speed/accel difference on the bike computer between the MA-3 and Velomax wheels. Should be a little something there....maybe 0.3-0.5 mph @ 40 mph.... but I know it will be hard to read in the real world.

Dan

I fully understand the logic behind the total weight issue but I must say that I ride a lot better on my 15lbs climbing bike than on my 17.5lbs crusier. Much more than the 156lbs body + bike calculation would predict, i.e. the difference should be just over 1% and only up the hills. I would dare to say that I find myself consitently about 1 gear higher on the lighter bike and accordingly about 1mph faster on a 30mile ride. That's 5 minutes! I have been discussing this with people before but I suggest to treat yourself to a really light bike once you reach your body weight goal. I started out about a year ago at 178lbs on a 22lbs bike. So that's 200lbs total. I averaged about 15.5mph. I trained really hard doing about 200miles/week. Within 3 months I dropped my body weight into the 160s and bought a lighter bike. I trained even more and before I knew it I was closing in on 155lbs all a while my new bike lost 3 more pounds to end up at 15lbs even. Now my starting weight is down to about 170-172lbs rider and bike and my average times are around 20.5-21mph for a hilly 30mile ride and I am having serious fun!

Wow, a full 1 mph difference is really pretty huge. Hard for me to believe that's just from the lighter bike. After riding my 4 lb lighter bike just a few times, seems to me it's going to be hard to measure the difference in performance. I'm riding and climbing faster on the new bike with the triple, but also going harder according to my HRM. Not sure how to get an objective measure of the differences in the bikes.

Seems to me downhill coasting would be a good measure of aero advantages, but climbing trials with an HRM would be tougher. I'll try to do some of this when we get some calm days. So far, all I can tell is that the Circuit Comp aero section rims are a bit harder to manage in the crosswinds than my old MA-3s!

Anyway, great results from your training and diet....you're doing some impressive average speed in the hills down there.

Could also be differences in your two bikes from the standpoint of rolling resistance and wind drag. As you know, tires, tire pressures, wheels, as well as your position on the bike all make a difference in performance, not just weight.

Whatever it is, hard to argue with big gains and serious fun!