Dreaded speed wobble

[V12man]

Even better.............Youtube it.............can be very entertaining until it happens to you.

 

 

Question: Was the rider riding with hands on the bars when he/she had the wobble?

I have never experienced a speed wobble whilst having my hands on the bars.

Not so funny on a chopper when I was a kid - hands on - down a hill called "tippers creek" - tipped me off a few times.... at speed.

[BaGearA]

put a little , emphasis on little bit of grease on your axels or sekwers stops noise and gets rid of speed wobble (In my experince speed wobble only started at 70 km/ph and the grease helped a lot)

 

Good luck

[J∆kk∆ls]

Achieved 78km/h. When wobble started I applied more weight to the front wheel and put in some peddle strokes. Keep a cool mind to, doubt can be your worse enemy.

[Martin PJ]

Happened to a mate of mine coming down Oliviershoek pass many years ago. Looked back to see a look of terror on his face and the front bars really wobbling all over the place. Never seen anything like it since. He was going about 50 kays and hour. That problem was traced to the headset bearings being a bit worn in, put new headset and the problem went away.

[DirtyFrank]

Even better.............Youtube it.............can be very entertaining until it happens to you.

 

 

Question: Was the rider riding with hands on the bars when he/she had the wobble?

I have never experienced a speed wobble whilst having my hands on the bars.

Never experienced a speed wobble on a bicycle but had a very bad one on my old BMW R100RS with my hands on the bars when I ran over a small branch in the road which set it off, took quiet a bit to settle the bike down, traced it to the headset bearings being worn and loose.

[Patchelicious]

Just do as the world champion does...

That's not the world champ, the world champ rides a Tarmac!

[Gen]

That's not the world champ, the world champ rides a Tarmac!

Someone mentioned world champ? [emoji322]

[RearWheelDrive]

I have experienced a speed wobble and it scared the living daylights out of me.

 

It was the 21st of Dec, a bright sunny day, birds chirping etc. I went to ride up a mountain pass (Van Rhyns pass in the WC) I rode up it and my wife and all the inlaws were following behind, my wife just started cycling and wasn't keen on the uphill. 

 

I got up the pass ok and started to descend. it was pretty hectic because it was between 9 and 11%. When the road straightend out my wife (Dare devil) comes flying past me and I thought I'd catch her. The funny thing is I was quite relaxed but  gust of wind at 62km/h and it started

 

First thought was "Huh what was that/" Followed by " This is probably going to hurt" I had my hand on the front brake and started to brake gently which calmed it down until I stopped. 

 

Haven't been past 60kph since.

 

I researched the crap out of it and what I found is, It seems to be a lateral acceleration of some sought that results in the wheels not following each other in a straight line the bike tries to correct this and the wobble is born. (Well this explaination made the most sense to me, I could be wrong though)

 

Bumpy roads, crosswinds, large frames, not enough front end weight, rider position/stifness all seem to contibute as well.

 

Maybe I'll get past 60 on the 94.7. Time will tell

[LOOK695]

Does this also occur with mtbikes?

[shawnvan]

Here's a good article on it (mainly Tri-bike focussed, but the same principles apply to all bikes:

http://www.slowtwitch.com/Tech/Speed_Wobble_5033.html

 

I've only experienced a speed wobble (on my bike) when freewheeling downhill and sitting up, taking weight off the front wheel. Putting weight back on the front stopped it straight away... but as the article suggests, the cause and fix of a speed wobble is very much dependent on your particular setup and "system"

 

Here's the summary:

 

"Here is the urban wisdom accumulated over the years by veteran riders:

1. Gripping the bars can be either good or bad at inhibiting speed wobble. The death grip of a rider who's shivering can present to the frame the very input that causes or sustains wobble. But a rider's arms and elbows are natural dampers that control a bike's tendency to oscillate, though a rider is not strong enough to stop speed wobble just by gripping the handlebars. So, yes, grip the bars, but not with a death grip. Rather, with a more relaxed grip (yes, I'm asking you to relax as you're soiling yourself in abject terror).

2. A number of riders report that taking weight off the saddle helps (lifting your butt an inch or two off the saddle), and gripping the top tube with your knees. The former changes the nature of the "system," and the latter adds stiffness to the system.

3. Slow down, until you're out of the velocity band that triggers speed wobble. But, don't slam on the brakes, locking the front wheel up.

4. Don't panic. Trust your equipment.

How do you fix a bike exhibiting speed wobble? Contrary to what you most typically read on the internet, your speed wobble is probably not a loose headset or a frame out of alignment. The way to "fix" speed wobble is to change something fundamental about the system. So:

1. Increase the stiffness of the system. Maybe this means a new, stiffer frame, replacing your whippy, small-diameter tubular frame. Or a frame the next size up, or of a different geometry, that takes up more of the space between the frame's main triangle and the handlebar.

2. Jettison mass that sits in front of, behind, or above the frame, and see if that makes a difference. This might be water bottle carriers. This isn't to say that these carriers are bad or cause speed wobble, rather than your specific bike that's giving you speed wobble has something about it that needs fixing. This might be the thing.

3. Make sure wheels are in balance, in round and true. Take your wheels to your LBS and ask them to perform this.

4. Just starting changing stuff out. It might be that any change in the system fixes the problem. Tires might be a logical and relatively inexpensive place to start. Aero wheels don't cause speed wobble. But maybe this set of wheels on this bike creates a system that wants to wobble at speed."
 

[LOOK695]

@henny, rider was with his hands in the drops

[Starvin' Marvin]

When it starts to vibrate and then it oscillates without being dampened, it gets worse and worse.  

 

A quick google search shows that any number of things could have cause it.  Can be something as simple as rider's position on the bike, to a technical problem with the bike itself - more specifically steerer or front wheel.

 

Look up speed wobbles for motor bikes, lots more posts on that.  Should have similar results for a bicycle.

 What Lizzy said. A increase in speed will cancel the oscillations. Also as mentioned, squeeze the top tube between your thighs.

[Patchelicious]

There is a lot of squeezing of thighs in this thread... Very Xenia Onatopp'y