Seen my first ever 'Speed Wobble'

[avsd]

I was out on the club run yesterday. With the good weather, dry roads a number of summer bikes made their first appearance. It was steady run with the normal club banter and sprints for the 30's signs.

On one of these sprints, which was down a straight hill on a clear road, 4-5 of the guys were going for the 30 sign. As one passed me his whole bike start to shake and he ended up in the ditch after a spectacular crash. Thankfully he was OK. bruised and a few scraps but the grass verge safe him from potentially serious injury. All the rest of the group got by him safely and there was no on-coming traffic as it was a quiet country road. I was doing about 56Km/hr or 36mph in old speak.

The initial assumption was that the wobble was caused by a puncture but that proved to be incorrect. It is now viewed as speed wobble. It was a very frightening experience. You might want to look at this link to understand how to manage a speed wobble should it ever occur to you.

http://www.cyclingtips.com.au/2011/03/speed-wobble-when-the-bike-shakes-its-head/

To misquote Hill Street Blues - 'stay safe out there'

 

[Andrew_Culture]

That's a bit scary! Fortunately my bike seems to get more stable the faster it goes.

Glad I read that link though.

 

[Friz]

Handy to know how to control it. Thanks for that...

 

[avsd]

That's a bit scary! Fortunately my bike seems to get more stable the faster it goes.

Glad I read that link though.

The strange think is that the bike was a new Cannodale Super Six and 40mph is well within that bike's design spec

 

[ColinJ]

I did the Kirklees Sportive/Brian Robinson Challenge 2 years on the trot with the same rider and he got a severe speed wobble both times at the bottom of the descent off Holme Moss! When he caught up with me he was ashen-faced with fright.

I'm fairly sure that it happened the second time because he was frightened by the memory of it happening the year before and tensed up.

On fast downhills like that I keep my weight forward, with my arms bent to absorb shock and vibration, unweight the saddle slightly, press down hard on one pedal (the outside one if I'm on a bend) and press one leg against the top tube to help dampen down any vibrations. I have not experienced any speed wobble problems so far.

 

[Rohloff_Brompton_Rider]

Bromptons do that if you attempt 'look ma! no hands' wouldn't fancy it at speed.

 

[Moodyman]

Shimmy's can be avoided/reduced to some extent by not moving on the bike during a high speed descent. Get into a position like Colin says and stay there.

 

[HovR]

If I load my Dawes up heavily on the rear rack it can get speed wobble on large down hills. Quite disconcerting at first, but once you get the hang of controlling it there's no issue. Just as the bike starts to wobble I ensure I have a loose hand grip (don't death-grip the bars) and clamp the top tube with my knees. A bit of controlled rear braking can also help.

 

[lozcs]

had a massive one on Friday....

http://www.cyclechat.net/threads/fromes-hill-herefordshire.125367/

thanks for the link

 

[Herbie]

thats

I was out on the club run yesterday. With the good weather, dry roads a number of summer bikes made their first appearance. It was steady run with the normal club banter and sprints for the 30's signs.

On one of these sprints, which was down a straight hill on a clear road, 4-5 of the guys were going for the 30 sign. As one passed me his whole bike start to shake and he ended up in the ditch after a spectacular crash. Thankfully he was OK. bruised and a few scraps but the grass verge safe him from potentially serious injury. All the rest of the group got by him safely and there was no on-coming traffic as it was a quiet country road. I was doing about 56Km/hr or 36mph in old speak.

The initial assumption was that the wobble was caused by a puncture but that proved to be incorrect. It is now viewed as speed wobble. It was a very frightening experience. You might want to look at this link to understand how to manage a speed wobble should it ever occur to you.

http://www.cyclingtips.com.au/2011/03/speed-wobble-when-the-bike-shakes-its-head/

To misquote Hill Street Blues - 'stay safe out there'

never happened to me...i never go supersonic on my bike so hopefully it'll never occur

 

[Andrew_Culture]

Reading all this is making me appreciate how good the mystery bike I bought is

 

[Radchenister]

Reminds me of flicking one of those gyroscope toys you used to get when young - surprised it could get out of control though, you live and learn.

 

[Cycling Dan]

First time I have even heard of this, rather scary stuff. Never had this problem though, but that could be down to my bike being £1,000 even the Allez got that to 50mph and nothing of this nature. The Allez was stable as the rock and easy to control.
The top comment for that video made me laugh
"HA! like smackin a fat chicks butt... *smack* wubwubwubwubwub =P"

 

[MacB]

never happened to me...i never go supersonic on my bike so hopefully it'll never occur

I had it happen on one bike at a bit shy of 30mph, the same bike had done that sort of speed, and up to 40mph, on many occasions. Never happened before or since but scared the crap out of me at the time, I'd never heard of speed wobble then. My first thought was front puncture, then broken forks and finally I'm about to crash. Fortunately didn't and was strangely relieved that a rider behind me stopped, along with others, to check on me but more importantly had witnessed it. Otherwise you could think you'd gone mad but he confirmed that the bike looked like a wet noodle for a short while.

 

[Radchenister]

Interesting point Dan, wonder if it would happen if they discounted it to £750?