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Weight distribution question(8 posts)

Weight distribution questionrengaracchi
Oct 1, 2002 8:31 AM
Suppose you carry 2L of water for a ride. Does it make any difference in terms of efficiency/performance if you carry it on you (such as in a Camelbak) or on your bike (in water bottles)? Differently put, if you have to carry some weight, is it better to make a rider heavier or the bike heavier? In either way, the total amount of the weight is the same.

My naive speculations are that if you make your bike heavier, it should be more difficult to make it to move, but on a downhill, your bike could be more stable. 2L of water is heavy in the world of cycling where 50g weight cut is a big deal. Granted that 2L of water is not a part of moving mass, I wonder if there is any difference you should consider at all. Any ideas?
Psychologyfiltersweep
Oct 1, 2002 8:40 AM
2L= 4.4 lbs... I think people like the "idea" of a lighter bike. It just doesn't make sense that wearing 4.4 lbs is any different than carrying it on the frame.

My belief is to keep the center of gravity as low as possible... and the rider as comfortable as possible... I'll stick to bottles.
re: Weight distribution questionSteve_0
Oct 1, 2002 8:44 AM
Total weight is total weight, so putting the weight on the bike will not make it more difficult to move; i.e, your body is still required to move 150 pounds (rider) + 20 pounds (bike) + 2 pounds (water), regardless of its position.

HOWEVER, if your BODY is carrying the weight (rather than the bicycle frame), youre body is extending additional energy to support it.

There may be some validity to your stability speculation, though, as the lower weight will create a (slightly) lower center of gravity.
More an issue of practicality ...Geardaddy
Oct 1, 2002 9:18 AM
Having the weight on you vs. the bike probably has little significance to overall performance. It's more about what is practical. If you're getting out of the saddle a lot, having the weight on your back kind of gets in the way. It just works much better when riding off-road because accessing the water is so much easier when getting jostled around. Plus, you have less access to refill when riding off road, so being able to carry lots of water is good.

Now if you look at aerodynamics, it is probably slightly better to use water bottles. Having a CamelBak on doesn't make you more aero. Also, I believe studies have shown that having a water bottle on the down tube actually improves the bike's aerodynamics.
improved aerosSteve_0
Oct 1, 2002 9:22 AM
interestingly, the majority of the tri-world carries their bottles behind the seat, primarily for aerodynamics (though some non-traditional frames simply dont have framespace for a bottle).

anyhooo, recent windtunnel tests with no bottles, bottles on frame, and bottles behind seat show the bottles-on-frame to be the most aero in all conditions except near-direct side winds.

Wish i could remember where i read that... triathlete mag maybe?

interesting.
I read that too, from a link posted here. Can't find it now...fbg111
Oct 1, 2002 2:36 PM
will post it if I find it.
less difference on a road bikelaffeaux
Oct 1, 2002 9:45 AM
On a road bike there's probably not much difference in performance (at least not for the average Joe). I prefer a CamelBack as it's easier to access, and I drink a lot more using it.

On a MTB, I'd never consider using water bottles again. When I first switched to a CamelBack I was amazed at how much easier it was to throw the bike around in technical situations. A couple of extra pounds is pretty noticable when you are lifting the bike, or throwing it side to side.
re: Weight distribution questionGMS
Oct 1, 2002 10:12 AM
Things get more complicated when you stand up and climb. I won't say anything definitively because it's not an argument I want to have, but I prefer the weight on me. Even so, I carry the bottles on my frame because I find it more convenient. I carry food/tools/etc. on me, though, as opposed to my old saddle bag.