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Weight and Speed(5 posts)

Weight and SpeedPatM
Jul 31, 2001 5:52 AM
I read the recent posts from NY Rider and Biking Viking and was wondering, and I am sure this has been discussed before.....
I looked at the BV spreadsheets for calulating speed to see if I lost lets say 10 pounds how much speed I would gain. Not sure if my assumptions were correct or not. I used the same power figure for both, same distance, no grade, no headwind etc.
The spreadsheet said that I would gain about a half a mile an hour over a 20 mile distance. That seems like a low number, when compared to people concerned over taking 1-2 pounds off the bike itself. Am I missing something or would loosing 10 pounds get a higher power number ? It seems to me that loosing 10-15 of fat would make a person a rocket
what you may have forgottenak
Jul 31, 2001 6:15 AM
some of us would have to have major surgery to lose fifteen pounds. For me, the only useless fifteen pounds on my body (ok it's like 3 oz, just let me dream) will not be removed because I may, at some later date when women wisen up, be able to find a use for it.
re: Weight and Speedjschrotz
Jul 31, 2001 8:24 AM
On flat ground, you probably wouldn't see too much gain in speed by losing 10-15 pounds. It's when the roads tilt up that you'll see the most improvement after losing weight. On the hills, you're trying to overcome the forces of gravity where the extra weight is your biggest liability. On flat roads you're dealing with wind and rolling resistance instead, and the effects of extra weight are less noticeable. I've known several guys carrying more than a few extra pounds that could still power along the flats with the best of them, but once the road went diagonal they disappeared.
There are two real issues here...mk_42
Jul 31, 2001 11:28 AM
In shaving off weight the issues are a little muddled because the reason the pros do it are different than most of the rest of us.

The pros shave the weight off the bike because they can't really shave it off anywhere else. They are (theoretically) at their muscle fat optimum mix and loosing any more weight off their bodies would make them less efficient and slower. Also, since they go so fast and competition is so tight a few grams here and there actually matter.

Then there is the issue that it's not JUST the weight. This makes a bigger difference to most of us. A bike that is much lighter just feels better, rides better, etc. and you will go faster on it because of it (not just because of the weight). Imagine riding a 30lb huffy...would it make you go only .5mph slower? It's kind of like proper form will make you go much faster than the theoretical aero gains if it feels good to you.
Another thing is that the lighter stuff is inherently higher quality and closer to what the pros use. For most of us, it's a perfectionists game. Lighter means better and we all want the best. One last thing (that people don't usually say) is that you can buy weight off the bike, but you have to work the weight off the person...

Also half a mile an hour over 20 miles is about 90 secs at 20mph and that's certainly better then a poke in the eye with a dull stick.

One more thing...Len J
Jul 31, 2001 11:35 AM
no one mentioned is the cumulative effect of weight.

The longer you are trying to push more weight, the more cumulative energy is required.