How can i overcome the speed wobble on my racing bicycle?

Question

This is also known as the 'Death Wobble'.

Answer 1

Take care of all mechanicals as listed in other answers. If you still wobble, riding technique can help or completely resolve the issue. By squeezing the top tube with your knees, riding smoothly, and trying several position changes may resolve the problem.

As far as positions, try moving fore and aft on the saddle or holding your rear slightly off the saddle. Try hold the bars on the brake hoods not drops or a top narrow grip.

One or several of these things together may work.

Answer 2

There are several things that can cause this. Some can be fixed, others cannot. Here are my top 10...

1) Excessive bearing play in wheels or headset;

2) Wheels out of round or out of true;

3) Failing rim(s);

4) Reflectors or other "weight" on the wheel;

5) Bad tire or inner tube(s);

6) Frame out of alignment;

7) Crack or break in frame;

8) Extreme upright angles on frame geometry;

9) Incorrect fork rake

10) Rider upper body weakness

If your frame is carbon fiber (all or part) or aluminum don't assume that the frame is aligned correctly. Although rare, there are instances where the frames were laid up or welded correctly but are at the very edge of the tolerance. High speed riding will uncover those slight errors.

Take the time to inspect for each of these items... deflate the tires and rotate them on the rim 90º, then reinflate. Take the tubes completely out and inflate them slightly to insure there are no major humps in them. Make sure that there is no bearing play... AND that the bearings aren't too tight.

Answer 3

I would also check the fork/rake combination. If this is off just a little you will setup instability in your handling.

Answer 4

This is normally caused by one of two things.

1) One or both rims are warped.

2) The alignment of the front and rear tire are not tracking in a strait line. One of the tires is offset (can be to the left or right) and needs to this be corrected.  (a person riding behind you can usually see this)

I had this happen years ago when I had a rear rim trued incorrectly, it had an offset of 3/16 inch and the "death wobble" appeared, when the offset was corrected the wobble went away.

Answer 5

I would like to know this as well, as I, too, have succumbed to the dreaded Death Wobble.

Answer 6

http://www.bicycling.com/qa_details/0,66...

Start by examining the front tire. If the tread is worn, replace the tire. The tire could also be improperly seated. If the bead wobbles or hops when you spin the wheel, let out some air, remount the tire and seat the bead all the way around. Also check the tire bead to make sure it isn?t broken. The easiest way to tell if the tire is the problem: Install a new one. Next, check the front wheel. Make sure it?s true and round. Then check spoke tension, which should be even all the way around on a front wheel. Also, the wheel should spin smoothly and without side-to-side play in the bearings. A misaligned fork can also cause a shimmy. The simple test: Measure the distance between the insides of the dropouts. It should be 100mm. If the measurement is off more than 2mm (and it?s hard to get the wheel in), have your shop align the dropouts. If the vibration doesn?t feel like it?s coming from the wheel or the fork, squeeze the front brake lever and push the bike forward and back. If there?s knocking in the stem area, tighten the headset. If it still shimmies, pull the fork off and see if the crown race is secure. After that, look at the rear wheel--is it in true and do the hub bearings turn smoothly? Some of today?s ultralight aluminum bikes translate a lot of road feel--what you perceive as shimmy might just be vibration. Finally, if you have a front reflector, take it off. Sometimes that unbalances the wheel at high speeds. TO PROPERLY SEAT A TIRE: A common cause of shimmying is an incorrectly seated tire. Push it away from the rim (one side at a time), then look down into the rim. If the tube is visible, it isn?t properly seated. Remove about 20 psi in the tube to get it out of the way of the tire seating and recheck. 10 CAUSES OF SHIMMIES 1. Worn front tire 2. Improperly seated front tire 3. Broken front tire bead 4. Out-of-true wheels 5. Uneven front wheel spoke tension 6. Improperly aligned fork 7. Worn hub bearings 8. Loose headset 9. Loose crown race 10. That goofy reflector From March 2002 Bicycling magazine