First High Speed Wobble!

[choke]

For those who haven't seen this, I'll just toss it into the thread....

Originally Posted by David Kirk

The Ti man hit the nail on the head above - speed wobble is the frame winding up torsionally and then springing back and setting up a wobble.

Typically it starts when something small bumps the bike off line....a gust of wind, a bump in the road...etc. This causes the frame to twist ever so slightly and the frame becomes a spring that then returns to its unloaded position and of course overshoots it and goes past center. And here's the kicker - when it does return and the frame suddenly stops twisting one way and is heading back in the other direction the weight of the stem, bars, levers...etc (all far ahead of the center of rotation of the headset) will continue to swing just a bit....this in turn makes the bike steer slightly to the side....and then the frame whips back the other way and with it the bar/stem/levers and they then steer the other way. This is "speed wobble."

A few things about wobble -

- all bikes can speed wobble. Every single bike ever made can be made to do it. Zero exceptions. I'm sure there are a lot of folks reading this and thinking "BS - my bike won't"....but I'm here to tell you that I can get on it and make it wobble every time. Fly me to your house and I'll be happy to prove it

The whole post... https://forums.thepaceline.net/showp...9&postcount=26

The full thread, which has more posts by DK that are well worth reading... https://forums.thepaceline.net/showthread.php?t=203949

[makoti]

Originally Posted by Louis

Check headset bearings.

The next time it happens try clamping the TT with your knees and see if that calms things down a bit.

Good Luck

This. I had one on two different bikes. Neither one had the HS properly adjusted.

[Hellgate]

Like others have said, check the head set. Odds are it's a bit loose.

Sent from my ONEPLUS A5010 using Tapatalk

[Ken Robb]

I have had wobbles on several bikes and changing the wheels on the worst offender only increased the speed where the wobble began. On another bike I only had the problem once. I was going down a familiar hill when a car came so close to my side that I moved off my usual line onto some patched pavement and the wobble set in BIG TIME. The guy riding behind me said it looked like my frame turned into a bunch of noodles.

[unterhausen]

it can happen on a bike that doesn't normally wobble, probably when you get too far off center and correct. I had a scary incident a couple of weeks ago when I got hit by a sudden heavy rain and started to shiver on the way down a big hill. That started a really heavy wobble. I was a little shocked and not fully with it that day and had to tell myself to put a knee on the bike. When the wobble stopped, I was still shivering and the bike started wobbling again. I had to tell myself to put a knee on the bike again. I think that might have been the most scared I have been on a bike, I definitely thought I was going down.

I'm pretty sure my handlebar bag had something to do with it. I need a fork with more rake on that bike.

[sitzmark]

Originally Posted by Ken Robb

I have had wobbles on several bikes and changing the wheels on the worst offender only increased the speed where the wobble began. On another bike I only had the problem once. I was going down a familiar hill when a car came so close to my side that I moved off my usual line onto some patched pavement and the wobble set in BIG TIME. The guy riding behind me said it looked like my frame turned into a bunch of noodles.

What was the speed range? I've had very little experience with wobble and it occurred around 50mph+, then stopping under 40. Haven't been with anyone who's seen it begin in the mid 30's and continue through 20's and teens until stopped. For that much energy to continue oscillating through the OP's frame at lower speed seems odd to me, unless there was something manually inducing it.

[11.4]

Ummm, go back and read Dave Kirk's comments on high speed wobble, as already suggested above:

https://forums.thepaceline.net/showthread.php?t=203949

All kinds of things can bring about high speed wobble; some can cause it one time only and never repeat, while others can cause a chronic problem. One can contribute to it with bearing load problems and changes in positioning that encourage the frame to wobble. It's worth checking the headset and ensuring the frame doesn't have a structural problem, but in a case like the OP's, it's almost certainly a case that you steered instinctively around a wind gust or you hit something on the road and in correcting for it, initiated a wobble. The pinch-the-top-tube-with-the-knees approach does help stabilize the wobble somewhat; mostly it gives you more comfort on the bike as the wobble subsides. I doubt the OP will see it recurring, but a wobble can happen at any time. I've seen it while riding on ice and overcorrecting, while riding downhill and getting hit by sudden sidewinds, riding fast and hitting a gravel patch and trying to oversteer through it, and so on.

There's a big hill west of Austin on Route 2222, known locally as the Wall. Coming down it, you get going really fast and then emerge, half way down, from between walls cut from the limestone plateau it descends from. The wind usually blows from the side there, and I've seen it catch more riders. Some just lose control and crash. Many incur a high speed wobble and either survive or crash. You don't even have to oversteer to bring about the wobble; the wind can induce it all on its own, though oversteering makes it worse or irrecoverable. Locals tend to know that on this hill, you just pinch your top tube heading down it; in fact, this is a something you'll notice pro riders do on a regular basis when descending, and it's for this very reason. So don't blame your bike, or yourself. If you don't do this on descents, do it. If you do encounter a high speed wobble, it'll be more controlled and you'll also feel much more in control of your bike just for feeling your knees on the top tube. Odd creatures we are, aren't we?

[Hellgate]

Originally Posted by 11.4

Ummm, go back and read Dave Kirk's comments on high speed wobble, as already suggested above:

https://forums.thepaceline.net/showthread.php?t=203949

All kinds of things can bring about high speed wobble; some can cause it one time only and never repeat, while others can cause a chronic problem. One can contribute to it with bearing load problems and changes in positioning that encourage the frame to wobble. It's worth checking the headset and ensuring the frame doesn't have a structural problem, but in a case like the OP's, it's almost certainly a case that you steered instinctively around a wind gust or you hit something on the road and in correcting for it, initiated a wobble. The pinch-the-top-tube-with-the-knees approach does help stabilize the wobble somewhat; mostly it gives you more comfort on the bike as the wobble subsides. I doubt the OP will see it recurring, but a wobble can happen at any time. I've seen it while riding on ice and overcorrecting, while riding downhill and getting hit by sudden sidewinds, riding fast and hitting a gravel patch and trying to oversteer through it, and so on.

There's a big hill west of Austin on Route 2222, known locally as the Wall. Coming down it, you get going really fast and then emerge, half way down, from between walls cut from the limestone plateau it descends from. The wind usually blows from the side there, and I've seen it catch more riders. Some just lose control and crash. Many incur a high speed wobble and either survive or crash. You don't even have to oversteer to bring about the wobble; the wind can induce it all on its own, though oversteering makes it worse or irrecoverable. Locals tend to know that on this hill, you just pinch your top tube heading down it; in fact, this is a something you'll notice pro riders do on a regular basis when descending, and it's for this very reason. So don't blame your bike, or yourself. If you don't do this on descents, do it. If you do encounter a high speed wobble, it'll be more controlled and you'll also feel much more in control of your bike just for feeling your knees on the top tube. Odd creatures we are, aren't we?

Yup, Tumbleweed Hill is not kind to bicycles.

Sent from my ONEPLUS A5010 using Tapatalk

[Ken Robb]

Originally Posted by sitzmark

What was the speed range? I've had very little experience with wobble and it occurred around 50mph+, then stopping under 40. Haven't been with anyone who's seen it begin in the mid 30's and continue through 20's and teens until stopped. For that much energy to continue oscillating through the OP's frame at lower speed seems odd to me, unless there was something manually inducing it.

As I recall the first incident was on an aluminum Trek and it started at 34mph. A tech from the shop took it down the same hill with no wobble. We swapped in some Rolf wheels for me to try and the wobble didn't happen---until I hit 36mph. :-) I bought a Lemond Zurich with Rolf wheels and it was much less prone to wobbles and the knee to the top tube trick worked. My CSi and Legend ti NEVER wobbled nor did my Kirk, Hampsten, Look, 3 Rivendells.
When I guy came to buy my Trek I told him about my wobbles and insisted that he take a ride down La Jolla Shores Drive from UCSD where it wobbled a LOT under me. He said it was dead stable for him. Both of the riders who had no wobbles on my problem bikes weighed quite a bit less than me.

[sitzmark]

Is unpredictable I guess. Just out for a ride and on a hill that has a typical coasting speed of 42-43 for me I tried my damndest to induce wobble once I crossed 35. Maxed out at 40. Pressured and pulled the bars left and right, then wiggled my hind quarters around and couldn't get more than 1 oscillation out of the bike once I stopped moving. 200lbs moving around atop the bike.

Doesn't mean much - everything about my system could be completely different. Just never have had any squirreliness out of a bike in the 30s range - except puncture or obvious malfunction.

[LegendRider]

I've only experienced high speed wobble once and, ironically, it was on a Calfee (actually a CarbonFrames).

https://calfeedesign.com/tech-papers/fork-symmetry/

[Saxon]

Thanks very much for the help everyone!
I'll check the head set. The tires and wheels look to be OK. According to the person riding behind me, I did make a fairly radical swerve (to avoid a reflector in the road) right before the fun started. There was also a pretty good cross wind at the time.

[shinomaster]

Originally Posted by Saxon

Thanks very much for the help everyone!
I'll check the head set. The tires and wheels look to be OK. According to the person riding behind me, I did make a fairly radical swerve (to avoid a reflector in the road) right before the fun started. There was also a pretty good cross wind at the time.

My worst wobble happend swerving around a rock. It was bad.. I was going fast down a mountain and It was terrifying!!

[11.4]

Originally Posted by Saxon

Thanks very much for the help everyone!
I'll check the head set. The tires and wheels look to be OK. According to the person riding behind me, I did make a fairly radical swerve (to avoid a reflector in the road) right before the fun started. There was also a pretty good cross wind at the time.

You just got your answer.

[dem]

My favorite reason I've heard for this is being too lean. A great excuse to add a few pounds of fat.

(Never had it happen myself