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unbalanced Zipp 303 question(6 posts)

unbalanced Zipp 303 questionsuperduperfast
Mar 28, 2002 7:13 AM
I just bought a new pair of 2002 zipp 303's.
Continental competition 22mm tubulars, vittoria tubular glue, and i have short aluminum valve extenders.
The tubulars i glued on correctly but now when i hold the wheel with my hands by the axle and spin
the wheel, it feels unbalanced. I think this is caused by the valve/extender but am not sure. How
can i correct this or has anyone else seen this?
re: unbalanced Zipp 303 questioncurlybike
Mar 28, 2002 7:40 AM
Put the wheels on the bike and ride! Seriously, every wheel tire combo will have this effect to some degree, don't worry about it.
re: unbalanced Zipp 303 questionsuperduperfast
Mar 28, 2002 7:53 AM
Over the years i have noticed slight unbalancing in spinning wheels but this seems a lot
more than just a little. I also have Rolf setriere's clinchers and see almost no unbalancing
when i spin it either in my hands. I talked to a guy that has 303's and noticed the unbalancing
and at high speeds it is quite noticeable and he had to counterweight it to
balance it out. Seems counter productive to getting a light
set of wheels ...
re: unbalanced Zipp 303 questionChen2
Mar 28, 2002 7:44 AM
That doesn't sound like a very accurate way to check balance. Once the hubs and grease are broken in you could spin the wheels on the bike and see if the stop with the valves at the bottom, probably will because of the extenders. But many wheels are actually heavier on the side opposite the valves because the rims are built with the valve holes opposite the rim seams. I always put my computer magnet on the light side of the wheel to help with balance. I also use the valve lock rings and plastic caps IF the valve is the light side. I suppose you could glue home made weights on the wheel if you are concerned with balance but that seems extreme and you're friends may think you are wierd or at least anal. Ride'm and check the balance later. (I use tubes with 60mm valve stems on my Cosmic Carbone clinchers with 57mm rim profiles instead of extenders.)
Mar 28, 2002 7:45 AM
If you use a computer, experiment with spoke magnet placement. Try putting it opposite the valve hole, or on the same side as the valve hole, and at different distances from the hub. You should be able to find a position that balances the wheel.

If it improves the balance, it wouldn't be too silly to put a magnet on both wheels. The maker of ADA wheels really swears by the benefit of having balanced wheels for stability's sake.
Don't get unbalanced over this.Uncle Tim
Mar 28, 2002 7:17 PM
There are a number of very good posts by Jobst Brandt on this subject that can be found on the internet. The bottom line is this: the physics that are at work on a bicycle wheel are much different from those on a car's wheel. Tiny additions of weight (i.e. spoke magnet, valve, etc.) will have no discernable effect when you ride a bicycle.

If you notice a little bump with each rotation, you have a more serious problem.