Bicycle Mechanics - Ticking from rear wheel

The last couple of rides, I've noticed a ticking sound which I'm sure is coming from the rear wheel. It does it whether I'm coasting or pedaling, so that eliminates the chain, pedals etc.

I've checked that it's not a broken spoke, cable hitting the rim or spoke, I've loosened the brake and it still does it.

It appears that the sound increases with the length of the ride, from barely noticeable at the start to being fairly obvious after 30 or so Km's. It doesn't seem to do it if I just spin the wheel, only when my weight is on it.

BTW, Mavic CXP 23 wheels, 105 drivetrain, Caad 3 frame.

Any ideas::confused:

loose spoke? check the tension of your spokes, as this can be a result of uneven spoke tension.

Thanks, I'll look into that.

Using a light oil (Triflow) lube the point where each nipple fits thru the rim. If that does not stop it the plug where the rim is joined may be loose. Even welded rims have this plug. You would need to take the tire and rim strip off and look at the join. There will be two dimples there. Take a pointy punch and give each one of those dimples a good whack, not to good or you will have an extra hole in your rim.

Thanks Rev, I'll try that, too!

I think this is the same problem that the Rev's first recommendation targets....
One of my Mavic OPs developed a loose bushing, and every time that section of the rim went over the ground, it ticked. The wrench isolated it by squeezing parallel pairs of spokes on both sides of the wheel, going backwards and forwards 'til the tick occurred, then reduced the rotation each direction 'til isolating the offending bushing. (With mine, it won't occur until you exert tension one direction, then the other.) If it's the plug, squeezing spokes won't cause it. The light oil works, but you have to re-treat every couple of weeks.

One other thing to check would be for cracks in the rim. I had a similar noise that drove me to the edge trying to find it. Finally took the bike to the LBS and it took them all of 30 seconds to locate the hairline crack. Replaced the rim and all was quiet again.

Paul

Thanks for all the replies! I oiled the spoke nipples and that appears to have solved the problem, although I haven't had a chance to ride it much since. But the last ride, no ticking!