EEEK! Speed wobble

Cubic

Don't fancy this happening much, but at least it looks controlable:

http://www.youtube.com/watch?v=xODNzyUbIHo

cee

he caused it at 2 seconds by removing his hands from the bars and slapping the stem with his right hand.....

i think it actually shows how stable a bike at speed is, as the wheel wants to stay straight, even if it does take a bit if a knock.

SpinningJenny

OMG :shock:

will3

I had a bike that did that if you rode hands off. Quite scary, but not disastrous.

Cubic

Yeah, I've heard that you're supposed to relax, hold the bars really gently and wait for it to subside.
Hmmmm, I think in my case the opposite would happen!

Stewie Griffin

I wont be trying that :shock:

mercsport

This use to happen a lot to me when , for years , I rode a skinny Vitus 979 Dural framed bike . Always at speed and downhill . Never really knew what kicked it off but they were times when I seriously wondered whether fate had decided my time was up and it was only moments to go before I was a 'goner' and I was face first into the tarmac . Never happened though and I never came off , but the trauma at 40+mph , sometimes , was enough to make me thankful for the mercies that kept me upright .

Was it Sheldon Brown that explained what it was all about ? Not sure , but I did read that bit about relaxing - this , when you're hyped up to the max - and letting it settle down of its own accord . Hmmmn , maybe . I did read that , yes , relax grip on bars , but also grip the top-tube with your knees and the quiver settles down in short order . This last , I managed to prove on a number of occasions before building about three or four more bikes upto the present which never gave a hint of the horrors that the Vitus gave me , and prior to that , an Aerospace ( it was branded thus ) .

dag_on_a_bike

Been there and hit the deck at 38mph!

See http://www.bikeradar.com/road/fitness/article/qa-speed-wobble-14776

and

http://www.bikeradar.com/road/forums/viewtopic.php?t=12585336

also

http://www.bikeradar.com/road/forums/viewtopic.php?t=12591241

a_n_t

definately helps to relax your grip on the bars.

mercsport

Further to that rather well shot vid' on the original post at top , I was impressed by the next one in line on YT 'speed wobbles' , which rather graphically displays the same phenomenon on motorcycles ( ..and have experienced too , long ago ) . It looked like it hurt very much but apparently he picked himself up and said he was OK : http://www.youtube.com/watch?v=RmtoOmq3 ... re=related

ollie cb

Now this will sound strange to anyone who has experienced speed wobble because hence the name, it "only" happens at speed.

But on my MTB (yes not even a road bike) wobbles going uphill. (yes even weirder) It's only on inclines of about 5% and occurs at a speed of about 18 mph. That isn't very fast for speed wobble either. Is there any way of explaining this? Because it is very out of the ordinary for it to happen on a MTB, let alone at that speed.

Oh and the bike is an '08 Specialized FSR XC expert.

nwallace

Your climbing faster than I normally go on the flat :shock:

My MTB has started to fish tail on descents when I get past 45kmh.

balthazar

mercsport wrote:

Was it Sheldon Brown that explained what it was all about ?

I'm guessing it was Brandt's article you're thinking of:

http://www.sheldonbrown.com/brandt/shimmy.html

mercsport

balthazar wrote:

mercsport wrote:

Was it Sheldon Brown that explained what it was all about ?

I'm guessing it was Brandt's article you're thinking of:

http://www.sheldonbrown.com/brandt/shimmy.html

Yes , quite likely .

There's also a thorough analysis in my copy of 'Bicycling Science' p.224 ( 2nd ed. ) under the sub-heading of 'Shimmy' in the chapter headed 'Balance and Steering' .

There is a third edition now to this wonderful book , but I haven't checked it out .

whydoesitalwaysrainonme

Have a look at this, really makes me cringe.
http://www.youtube.com/watch?v=RmtoOmq3ppw&feature=related

nwallace

whydoesitalwaysrainonme wrote:

Have a look at this, really makes me cringe.
http://www.youtube.com/watch?v=RmtoOmq3ppw&feature=related

At least he was able to post the video himself afterwards.

http://www.youtube.com/watch?v=XiKmPFo6 ... re=related

Alive enough to post this video of himself! Broken shoulder, ribs, ankle, lost a finger... not bad considering!