Bicycle Mechanics - wheel balancing?

I just got a new pair of Campy Zondas. Somewhere it said something about balancing the wheels. They seem to be trued. I have mounted the tubes and tires. However when I spin the wheel it feels lopsided, i.e. out of balance, as if someone had placed a weight on one side. What exactly is this? Do I need to be concerned? Is this something I can learn how to dial-in myself?

Originally posted by flyefisher
I just got a new pair of Campy Zondas. Somewhere it said something about balancing the wheels. They seem to be trued. I have mounted the tubes and tires. However when I spin the wheel it feels lopsided, i.e. out of balance, as if someone had placed a weight on one side. What exactly is this? Do I need to be concerned? Is this something I can learn how to dial-in myself? Sounds like BS to me.the valve stem is more weight on one side.Add a spoke reflector on the other side to balace it out.

Bicvcle wheels are trued and dished, but not balanced. My boyfriend Pokey is a little gruff, but right. If you have good hubs, the weight of the valve stem will make a heavy spot on the wheel. It won't affect performance though! ;)

On my Open Pros and other Mavic rims, the heavy spot is actually opposite the stem... I assume the rim was welded there. Don't know about other brands.

When the bike is suspended, rotate the heavy side to 3 or 9 o'clock. (For a rear wheel, you have to take the chain off the cassette, or just take the wheel off and hold the axle in your hands). How fast does the heavy side fall to 6 o'clock? If the bearings are in good shape and adjusted right, it's perfectly normally for it to slowly rotate down, and oscillate a few times like a pendulum. If the heavy side drops fast, then it is unusually heavy.

OK, cool. The only reason I asked was because my mavic open 4 CDS on my other bike spin without any such imbalance. I guess I'll have to try your test and then finally ride them and see if there is anything funny about that. Can't wait to ride my new bike - Klein Quantum with new campy chorus and the Zondas. I'm waiting on a funny-sized seatpost and then it's off to the roads! Thanks all for the advice.

I checked it last night and it's actually opposite the valve stem where the extra weight is. Perhaps I will add some of those screw tighteners to the valve stem to balance it out. Too bad weighted ones are not made.