spin1moretime

Does anyone have this problem? Just came down from the peaks, and three times the front wheel tried to shake me off the road. It seems to be after I hit over 35 mph. At 60 plus it’s a bit concerning, I don’t bounce as well as I used to.

trailangel

I don't get the death wobble until over 70mph.

FiftySix

Do bike shops offer spin balancing for bicycle wheels?

350htrr

I only have that problem when I go down hills and am hands free... I think sometimes the tube is not completely settled in properly and there's a heavy spot in the rotation, creating the wobble... JMO...

jppe

Try pressing your inner thighs against the top tube or slightly raising your butt off the saddle. I agree that’s it can be pretty scary.

79pmooney

Death wobbles are from just the right (wrong?) combination of factors. Fork stiffness,fork and frame geometry, small issues like headset adjustment and quality, you (someone else on the bike probably will not be able to reproduce the wobbles), One thing that often makes them far worse is fear and tensing up, especially your hands and grip. A way to stop the wobbles is to place your knee against the top tube. If that isn't enough, use your other knee as well. I find being underdressed makes my best bike a lot worse.

big john

Is it the first time on this bike with the same set-up as when it didn't shake? Much has been written about this on this forum and elsewhere.

If the bike just started shaking it might be loose spokes or even the headset. Try a different wheel if you can. Some bike/wheel/rider combinations just result in wobbles. Try pressing your knees against the top tube, as jppe said, and moving your weight around on the bike.

Maybe take it to a shop if you don't do your own work. I had a friend sell a bike because he couldn't get rid of the shake.

Iride01 

Some bikes do it at lower speeds and some don't do it at all. Or at least not at speeds I've gotten too, which aren't as fast as you guys apparently can go. Never seemed to matter about tires, tubes or bearings on the one I had that was bad about it. Sometimes my weight distribution could mitigate it. I got rid of that bike long ago.

big john

Meaning that you shake from the cold? I ask because I saw that with a friend coming down from Onyx Summit on a cold day.

79pmooney

If your bearings are good, you can just watch to see if the wheel rotates. (Install the rear wheel with the chain not around the cassette.) Add weight as needed until the rotation doesn't happen. (My "just thought up" crude approach - apply chewing gum opposite the valve until you have it balanced. Weigh that gum on a gram scale, Buy a fishing weight of that weight; one of those that you crimp around the line, Crimp it to the nearest spoke. But caution, this advice has had less review time than I spent typing it.)

79pmooney

Yeah, when I am cold, doing the relax gets a lot harder. I have a very fast 1000' drop on a ride I do fairly often, I've learned that it is a cool day, my ride is far better if I bring the clothes to be overdressed for that hill even though I have to lug those clothes up and pull them off after the descent. (I always stop at the mountaintop park so putting the clothes on isn't an issue.)

Iride01 

These offer some more reasoned thinking on it. The bike I had the shimmy in was a very tall frame and headset.

Scroll about halfway down in this first article.
https://www.velonews.com/gear/road-g...nnard-zinn-14/

This is older thoughts on the issue.
https://www.velonews.com/gear/101285/

cb400bill

Happened to me once at 48 mph. My front quick release was this >< much to loose. Scary stuff.

big john

Interesting. I've never has a shimmy and I use 62-64cm frames, including a standard diameter Prestige tubed Landshark which was a wet noodle on the stiffness scale.
The guy I knew who sold his bike over it was much shorter but that one bike was the only one he had a problem with.

spin1moretime

Thanks all for replies and suggestions. It’s an old 80’s frame, if rebuilding the wheels and headset doesn’t fix the problem maybe it’s time for an upgrade. I feel like I’m trading the wife for a younger model, just not right after all this time.

skidder

Since you mention its a 1980's model bicycle, has the fork been changed on it? If so, that usually changes the geometry and handling. I changed the fork on an older bicycle and it rides great at normal speed, but starts wobbling on downhills at around 30mph (estimate). I still have the bicycle and ride it occasionally (its fits me perfectly), but leave it at home if I'm planning to ride in a hilly area.

More extreme - I took an old rigid MTB and put a new rigid fork on it made to replace 100mm suspension forks (trying to get the front end and handlebars up higher), and that thing will not allow you to ride 'no-hands'; it wants to 'flop' right or left; its not a severe pull in either direction, just when you release the handlebars. It still works and is comfortable on longer rides that are not at excessive speed, but I have to keep at least one hand on the handlebars.

rowerek

if you have more than one bike and extra wheels, i would just replace front wheel with a different one and see if that fixes the issue. Wheels are relatively cheap this days, especially used ones, as people keep upgrading to the latest technology. Wobble at high speed is scary, I had one while rollerblading downhill well beyond point of no return, putting some extra weight on offending rollerblade saved me from a serious spill, lesson learned.

First suspects are balancing and bearings. Balancing could be assessed in a rudimentary way by rotating wheel (bike upside down) by 180deg from the rest position and letting it go and see how fast it goes back to equilibrium.

pdlamb

Speed shimmy is surely scary.

Most of the time I've had shimmy it's been because I've stiffened up (cold or nerves), and relaxing a bit, changing position, and trying to get my thigh against the top tube have dealt with the problem. If you do brake, make sure you stay very light on the front brake; that'll just make it worse -- use the rear brake.

Other factors have been severely out of true wheels, wheel bearings not adjusted correctly, and there's one hill in town that just has a bad combination of pavement, curves, and the topography is such that it buffets me with cross winds whenever the wind speed is over 12-15 mph.

Again, relax, slow gradually, dampen the shimmy with your leg against the top tube, and you'll live through it.