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lighter bike better than lighter body...(17 posts)

lighter bike better than lighter body...esbike
Mar 18, 2002 10:30 PM
I've heard so many people respond to comments about which bike part is lighter with "why don't you just lose a few pounds off yourself?". So, I took that to heart and lost about 10 lbs. I definitely feel a difference when climbing. But when I ride my commuter bike which is 23-24 lbs, I feel far slower than I ever did when I weighed 10 lbs more and was riding a 19 lb bike. This makes me wonder, maybe losing weight off the bike is more valuable than dropping weight off your body?
re: lighter bike better than lighter body...TSlothrop
Mar 18, 2002 11:03 PM
I don't know what to say to this, other than I think you are probably wrong. Unless: have you very recently lost all that weight? If yes, perhaps you've lost a lot of energy in the process. If that's the case then you'll soon regain it, and be motoring along.
re: lighter bike better than lighter body...liv2padl
Mar 19, 2002 4:16 AM
well, look at it this way .... no matter how much YOU weigh, would you rather carry a 20 pound garbage can out to the curb on garbage pick-up day or an 80 pound can. dunno, is that an analogy or does garbage just stink no matter how much it weighs. ;-)
re: lighter bike better than lighter body...SteveO
Mar 19, 2002 5:31 AM
look at it THIS way... ROLLING a 20 pound garbage can out to the curb requires a de minimus of effort more than ROLLING a 17 pound garbage can to the curb. Negligible, IMO.

It'll be more pronounced when rolling that can up a hill, but then again, i'd also prefer to be lighter in body weight when doing so.
Flats vs. Hills questiontz
Mar 19, 2002 5:51 AM
Theoretically, when riding on a flat you only have to overcome air resistance. Therefore, the main factor affecting your speed should be your muscular strength, not the weight of your bike [within reasonable limits, of course]. Is that true? How significant is force of friction in all the ball bearings?
When climbing, however, you actually do work, by pushing yourself and your bike up the inclined plane. Only here your body and your bike weight should really come into play.
Am I right?
Yes, you are right!Nessism
Mar 19, 2002 7:29 AM
tz wrote:
"Theoretically, when riding on a flat you only have to overcome air resistance. Therefore, the main factor affecting your speed should be your muscular strength, not the weight of your bike [within reasonable limits, of course]."

and

"When climbing, however, you actually do work, by pushing yourself and your bike up the inclined plane. Only here your body and your bike weight should really come into play."

There is one more situation where weight matters, when accelerating. Force = Mass x Accereration. More mass requires more force for the same accereration.

Regarding loosing speed with loosing weight, this may be true if the rider lost lean muscle mass. If the weight reduction was due to fat loss, more likely if the weight loss was achieved through exercise, the speed loss may be due to low blood sugar levels causing fatique.

I'm all for light bikes. But at some point I think the cost to performance ratio gets skewed toward cost. And I'm not in favor of pinching every gram from places that matter such as the frame and wheels. Of course, this is said by a guy that could stand to loose a few lbs. of fat himself.

Ed
Angel Casero said...aet
Mar 19, 2002 6:33 AM
He lost some TT speed but gained climbing ability when he lost weight. of course he is a world class athlete.
Both...DINOSAUR
Mar 19, 2002 7:52 AM
You need both. You need to drop as much weight without losing a lot of muscle mass, and you should be riding a "reasonably" light bike. By "reasonably", I mean something under say 20 lbs. A light bike will be more responsive and more fun to ride. Which will be sort of a double edged sword. The more you ride the more weight will come off. Not to say a heavy bike will hold you back. One of the top miles rider for my cycling club was riding a 24 lb bike. However he switched over to a ti bike and noticed the difference immediately in weight reduction.
re: lighter bike better than lighter body...binladen
Mar 19, 2002 8:02 AM
1. if you lost 10lbs fat, then it's not a problem, your body make take a while to adjust to the weight loss;
but if you lost muscle, then you have lost power, if it can be made up by the advantage in climbing, then it's worth it. Of course it depends on how much you have improved on your climbing, how much climbing you do, and how important it is to you.
FWIW, I'm with Ed and Dino--and I just lost 40 lbs.cory
Mar 19, 2002 8:22 AM
Last summer I realized I'd been proud of myself because I'd gained "only" about two pounds a year through my 30s and 40s...but after 20 years, I was still carrying 40 extra pounds. I took the weight off (diet and exercise, what do you think?), and the difference was amazing. I've always been a lousy climber, and suddenly I'm in the middle of the pack.
That amount of weight makes more difference than anything you can take off a bike, of course, but then I switched bikes, too.
My main road bike is an Atlantis, which I love but it's set up for touring and fire roads and it's a little heavy. I got out the old Allez, probably three or four, maybe even five pounds lighter, and rode that for awhile. I FELT faster, because it has steeper geometry and it's a little more nimble and moves around under me when I stand to climb and things like that. At the end of the ride, though, I hadn't GONE any faster. I think taking weight off the bike contributes more to the feel of liveliness than it does to speed.
Well, I don'tdjg
Mar 19, 2002 8:39 AM
mean to ask a stupid question, but apart from the reasonable questions about blood sugar/dieting, etc., I wonder whether some of the difference is in the wheels. Lighter wheels mean not just reduced weight but reduced rotating weight. And better tires (albeit, maybe not better for commuting) might mean not just less rotating weight but less drag and lower rolling resistance. Also, the aerodynamics on your commuter may (or may not be) significantly worse. Is the position more upright? Are you towing stuff around with you? Beats me.
I agree. I notice a real speed differencemorrison
Mar 19, 2002 8:50 AM
b/n my Mavic Cosmos w/ commuter tires and my Velomax w/ Michelin pros. It's a factor of rotational weight + aerodynamics. Then again, maybe it's all psychological.

BTW, I put on about 30 lbs over the past 2 yrs, and took 25 off over the last 5 months. Huge difference over last summer in terms of climbing ability and speed on the flat.
Cycle Sport Magazine, March issue...DINOSAUR
Mar 19, 2002 8:56 AM
Has an article relating to this subject, "Effect of Body Weight and Size on Cycling Performance", by Ed Bruke. Lots of good information, bottom line is that there is a trade off. I remember Lance Armstrong saying that his cycling really took off when he dropped 15 pounds because of his illness...
re: lighter bike better than lighter body...netso
Mar 19, 2002 9:34 AM
Assuming you are fit:
200# - I go really fast downhill and on flats
Uphill - really poor

185# - Downhill not as fast
Flats are abot same
Hills are much easier
It's in the wheels!!!KLM
Mar 19, 2002 10:51 AM
Rotational weight is critical. Adding 5 pounds to your bike frame is nothing compared to adding just 1 pound in your wheels. When I put a pair of 35c bullet proof steel belted tires on my commuter bike I slowed dramatically from the 20c kevlar bead tires they replaced. But hey, at least I don't get flats anymore, which is what you want for a commuter anyway. Your commuter bike probably has rims and tires that are twice the weight of your 19 pound road bike. Just for fun try putting your race wheels on your commuter and let us know what you think. I bet you'll feel like you lost those 10lbs all over again.

Best of luck,
Ken
Common misunderstandingKerry
Mar 19, 2002 6:38 PM
Of course light wheels are important, but so is light everything else (including the rider) when climbing. The 5/1 ratio stated here is preposterous. In fact, WHEN ACCELERATING rotating mass at the rim requires 2X the kinetic energy to spin up than the same mass anywhere else. Once the bike is up to speed, the kinetic energy is constant, and it takes no more energy to move a 1 lb. water bottle down the road than it does an extra lb. of wheel weight. Plus, you get that KE back when you coast. The only place that wheel weight is signficant (compared to any other kind of weight) is in a situation where you are accelerating a lot, and then scrubbing speed with your brakes (like a criterium). And even there, a pair of l lb. heavier wheels would take about 1% more energy in a one hour crit with 160 accelerations.
tiresgtx
Mar 19, 2002 9:14 PM
Assuming you have a proper fit/position/setup on both bikes, put the same tires at the same pressure on both bikes. Then see what kind of difference you feel.