Goofy question I know

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Goofy question I know

Postby carbonismyfriend » Sat Sep 07, 2013 7:59 pm

Would weight lose on the bike (not the wheels) be better felt while riding, than weight lose on the body? I say the bike for small (several pounds). The body if your talking a lot of weight (20+ pounds). I know this has been discussed somewhere before.
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Re: Goofy question I know

Postby ScubaCruz » Sat Sep 07, 2013 8:58 pm

Weight loss on the bike is instantaneous and felt instantaneously, like WOW! The body on the other hand is overtime and not so instantly felt but amazingly once seen through results is felt with pride and accomplishment!

For me, new 'racelite' wheels were like WOW, there is a difference. Then there was the year after an honest winter of training and diet, the following race season was like 10,000 WOWs because 'I did that!'
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Re: Goofy question I know

Postby gexas » Thu Sep 19, 2013 7:56 am

i would agree with scubacruz. to shave a few pounds off the bike usually costs $$$ and can typically be detected only over long mileage in my opinion. weight loss on the body because it slowly comes off is harder to notice. a good way to see what 5 or 10 lbs feels like off your body is to fill a 3 liter camel back up with water and ride for an hour. take it off and ride the same amount. removing this 6lbs of water gives you a idea of what loosing body weight will do. less strain on the back, less weight for the legs to carry when you pull up a long climb out of the saddle and more dexterity on the twisty stuff. it is significant i promise.
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Re: Goofy question I know

Postby Glagola1 » Thu Sep 19, 2013 9:09 am

The main difference between weight on the body and weight on the bike is that the bike is "unsprung" weight when compared to the body which is floating on your arms and legs. When you hit a bump, your body is isolated from this force and absorbed by your limbs. You bike on the other hand takes the full force of the bump and is moved in the opposite direction of the force of the bump.... which your body has to deal with. If your bike weighs less, the momentum generated by the force of the bump is less and your body spends less energy keeping the bike under you.

So basically, you have to spend energy to ride. That energy is spent in two ways: propelling you forward and dealing with the trail and what it does to the bike.
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Re: Goofy question I know

Postby tenbsmith » Fri Sep 20, 2013 12:42 pm

All the previous posts are good, especially Scubacruz's observations on perceptions of the impact of weight change.

Weight loss from the body or bike probably leads to similar improvement in performance. Loosing weight from the body has the performance advantages of lowering center of gravity and decreasing effort related to supporting that weight. Based on that, there may be a marginal advantage to body weight loss in most cases.

As for decreasing bike weight, people put higher value on decreasing unsprung and rotational weight. Unsprung mass is anything below the suspension; lowering it helps wheels and shocks react more quickly to bumps. Rotational mass is anything attached to the wheels; lowering weight here improves acceleration more than decreasing weight elsewhere because you are decreasing mass you must move forward and spin. In bikes, I suspect the benefits of decreasing unsprung or rotational weight are marginal and may only be important in competition or longer rides.
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