A scary moment

[Rob W]

Going down Reigate hill the other day,i was just touching about 30mph when my front wheel started wobbiling and it just got worse as i went down the hill.I just managed to bring myself to a stop before crashing.I have knowen this to happen before on the same bike.Wheels and everything seem to be ok.So the question is what the hell is going on.It was like trying to steer with a jelly wheel.

[Will]

I think it's known as "shimmy"

I had it happen on one of my bikes once and I never did work out what caused it

Might be worth googling, and someone like Sheldon may have some ideas

[DavidKennett]

Worth a [url=http://www.bikeradar.com/road/fitness/article/qa-speed-wobble-14776]read[/url]

[youtubewww]http://www.youtube.com/watch?v=RmtoOmq3ppw[/youtubewww]

[Rob W]

Looking at the video that was just how my front wheel was going.At least he had leathers and a crash helmet on for the crash.Luckily i was able to bring myself to a stop.Just.

[Mike I]

I got into a fairly hairy speed wobble on last year's IoW trip. I think it was a combination of a sidewind hitting me and being too tense. I remembered some discussion on here about the gyroscopic effect and that braking can make it worse. So, against my better instincts, I let go of the brakes and started pedalling again. It worked for me, but obviously I take no responsibility if it doesn't for you .

[Andrew G]

I think I've seen the pedal out of it tip Mike, good to hear it works. I've not had one myself but I gather another thing to do when raising you bum off the saddle is to ensure you keep your elbows and knees soft. Any rigidity in your body will exacerbate the problem.

[huw williams]

[quote="Rob W"]Going down Reigate hill the other day,i was just touching about 30mph when my front wheel started wobbiling and it just got worse as i went down the hill.I just managed to bring myself to a stop before crashing.I have knowen this to happen before on the same bike.Wheels and everything seem to be ok.So the question is what the hell is going on.It was like trying to steer with a jelly wheel.

[adrian]

The problem is that all the remedies seem counter-intuitive: you need to relax just when you feel nanoseconds from biting the dust (while you yet have teeth to do so), and take control just when you feel you've lost it in a big way. I've had one or two of these and in my case I'm sure they were caused by a build-up of tension in response to a high-speed descent of an unfamiliar road with a poor surface.

[Rob W]

Trying to remember all these remidies as i`m flying down hill is all well and good when my life is flashing before my eyes.But its trying to remember whos idea to use.

[Rob W]

And there was me going to strap a clip board to the handle bars so icould write all the ideas on and tick them of as i desend as to which one works.

[Snoop Doug]

Happened to me going down Star Hill last yr on Hell of Ashdown. I was on wrong side of road heading for oncoming traffic ready to bail and somehow I managed to get the bike and me out of the way and down the hill. I think I was lucky as the hill began to flatten. I also have a vague recollection of a big wobble just as I went down on the tram tracks. There's summat in ma heed and I cannae shift it.

There was an interesting letter in the Oct/Nov CTC mag about this. Some very useful info - can you get hold of a copy? If not I will write it up on here but may take me a while to get round to it.

Good luck - Snoops