Speed wobbles - help!

[Spider1977]

I have a new lightweight carbon frame (61 cm) with Ksyrium Elite wheel set. I have had speed wobbles on three occaissions in past three months. Each time it has been wet and I have been in the middle of a hard ride on a descent after a good climb.

It usually starts at around 60kph. I'm not sure whether it's me or the bike. As it has happened on only these occaissions it must be me, as I've done heaps of other descents at faster paces, no problem. It does affect confidence though.

The point is once it starts, how do you stop it? It's frightening, I just try to hold a straight line and apply light pressure to the rear brake to slow down. Any substantial steering is out of the question, so it can be quite dangerous. I've had one person recommend putting more weight on the bars, but as the ressonance gets into the frame, it seems to me the frame would wobble more if I took weight off the saddle.

Does anyone else have any recommendation on correcting the problem in mid flight?

 

[rule62]

Do a thread search while you are waiting for responses. This topic has been covered at length before. Sorry but I don't have the threads bookmarked.
Good luck with it though.

 

[keydates]

Try clamping your legs on the frame.
Relax. Tensing up is never good.

There's probably more, as the previous poster mentioned.

 

[Spider1977]

Thanks for the suggestion. Thread search did reveal a number of posters who had specific problems with Mavic wheels. I got my bike back from the LBS yesterday and had a couple of good descents with no problems, although I did hold back - need to regain some confidence.

Seems the Mavic hubs can loosen up, giving some lateral movement. Looks like I might have to invest in a M40123 tool and periodically check hub pressure.

Other advice about lightening grip on bars and clamping top tube with knees, I'll keep in mind if there ever is another "emergency". I agree, any tension in grip always leads to problems.

Cheers