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Balancing Carbon Wheels

Jul 27, 2009
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Does anyone have any advice on how to balance a carbon wheel that is slightly out of balance? A link to any articles or anything would be helpful.

Basically the front is slightly out of balance, it's just started lightly pulsing under braking. Do you add small weight somewhere?

It's a Reynolds Assault wheel.
 
Jul 27, 2009
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Is it actually the balance or just the braking action itself that causes the pulsing when braking? you can put weights on spokes on the light side of the wheel if its really out of balance. hold the hub with an outstretched arm and spin the wheel fast, if your arm starts to wobble the wheel is out of balance. otherwise its your brake pads. carbon braking surfaces aren't the most consistent.
 
Jul 27, 2009
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Yeah, it's got a slight pulsing when I spin it up in my arms so I guess it's slightly out of balance. Will have to find some weights for it I guess.
 
Mar 18, 2009
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Try a better set of brake pads, I have run the zipps, and a few other carbon specifics. The Swiss stops Yellow seem to work the best. well worth the extra couple of bucks.
 
Mar 4, 2009
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probably not a balance issue

Your wheel might very well be slightly out of balance but if the problem you're *noticing* is brake pulsing, I'd first try cleaning off the rim especially if this is something that has only developed recently. I'd bet that if you were note the location where the pads are grabbing, you'll find some residue building up there, too. Clean with isopropyl alcohol first then move to acetone if the former doesn't work.
 
Sep 30, 2009
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YOu can do what I did for my Zipp 440's. I found the rims to be out of balance, called up Zipp and they told me that the spec for those rims was 20g or under to be out of balance. I managed to pick up some coated lead foil (the kind your dentist uses in your mouth for x rays), peeled the coated off and stuck them onto the rim. They work great because each piece of foil weighs 1g, so your balancing will be very accurate. I covered the foil with some black heavy duty masking tape, took the wheels for a ride, and problem was solved.
 
Jun 19, 2009
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twothirds said:
YOu can do what I did for my Zipp 440's. I found the rims to be out of balance, called up Zipp and they told me that the spec for those rims was 20g or under to be out of balance. I managed to pick up some coated lead foil (the kind your dentist uses in your mouth for x rays), peeled the coated off and stuck them onto the rim. They work great because each piece of foil weighs 1g, so your balancing will be very accurate. I covered the foil with some black heavy duty masking tape, took the wheels for a ride, and problem was solved.

If you've got any carbon rims with applique' decals on them; remove them with a heat gun or hot hair dryer first. Unless you are paid to ride them they only add weight and contribute to the problem. They also fade and look ugly later.
 
Due to the deep section is it the extended valve causing a weight imbalance? (turn the bike upside down, spin the wheel and see if the valve ends up at the lowest point) I found that on my wheels and for some reason it was more evident on the front. 'Solved' it by placing my speedo magnet on the spoke opposite the valve with a pinched small lead fishing weight attached for a little extra.
 
Sep 30, 2009
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Oldman said:
If you've got any carbon rims with applique' decals on them; remove them with a heat gun or hot hair dryer first. Unless you are paid to ride them they only add weight and contribute to the problem. They also fade and look ugly later.

I couldn't. Mine are in the protective gelcoat. I took in every balance factor before sticking my weights on.

Also make sure that when you mount your tires, you have the label of the tire where the valve stem is. This was an old wives tale when it came to aluminum rims, but it always seemed to work for me as well. The label is the heaviest part of the tire, and the valve stem isn't heavy enough to offset the pins and welds on the opposite side of the rim. Not sure about carbon rims tho.