The front end of my '03 Dual shimmies at speeds greater than 30mph. The bike is new and other than flipping the stem for a more comfortable aero position and adding a saddlewing holder the bike is straight from the factory. Any thoughts?
The shimmy checklist:
- Are both wheels in straight?
- Was bike crashed or transported on fork mount roof rack?
- Is the headset correctly adjusted? (not too loose?)
- Are hubs adjusted correctly?
- Is there fork/front dropout damage?
- Is the frame broken at the downtube/headtube union?
Just a start.
What front wheel are you using?
I used to have bad speed wobbles when I used a HED3 in front. I finally traded it in for an HED Alps.
So, Tom - tell me more about the fork mount roof rack issue. I will be travelling from WI to Memphis, St. Louis, and a few other 2 or 3 hour trips this summer. My fork-mount Yakima is the way I move my Dual and my wife’s P2K.
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What causes problems with this
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Any way to reduce risk?
The problem results from the fork dropouts not being adequately clamped in the rack fork mount, or being clamped down way too tight as is the case with manufacturers who favor oversized QR skewers for added rack durability.
Fork dropouts are designed to hold the wheels in the fork but not hold the entire bike on a rack. They aren’t supposed to support that load.
Taking the bike in and out of the roof rack can and does often bend the dropouts. It is unlikely this would cause frame shimmy at speed, but could be a contributing factor.
The best way to avoid this, and I apologize in advance for being obnoxiously obvious, is to devise a method of transporting the bike inside your vehicle. If you already own a quality (expensive) rod rack system then you may consider a cargo box for the roof to put your gear in and then transfer the bike to the inside of the vehicle.
Good luck!
Could be the hubs. the other five i have looked into. thanks for your help.
no fun wobbling at those speeds!!
i have ksyrium elite wheels
Yours didn’t come from the factory with those wheels, did it?
what about an internal headset? how do you adjust these? i feel mine may be a little loose, on my soloist.
Leonard Zinn has written alot about this in Velonews. The main cause, when a mechanical defect is the cause (see Tom D above) is flexing the Headtube. Typically, the problem occurs with a big rider on a big, lighter weight frame. When it happpens while riding clamping the toptube between your legs may stop it. A more permanent fix may be to try a different fork, particularly one with a different steerer tube material.
Shawn
my bad, they were an upgrade. now that i think about it it also came with the more aero carbon fork found on the P2k.
You adjust them the same as any other headset, loosen the stem, tighten the top cap, tighten the stem again. But if you have to ask, you should probably have it done by a professional.