speed wobbel, help!

chrisannear87

is there a cure? Ive had it three times now and it scared the sh*t out of me! the first time was on a long down hill just before a bend @ 47mph, second time was on the Dartmoor classic this year around 40 ish, and the last was the other night on a straight road @ 37mph?

bike: caad10 '2012'
wheels: da 9000 c24
tyres: gp4000s @ 110 psi
my weight: 72kg
my miles:
http://www.strava.com/athletes/cannear




thanks Chris

Cubic

I used to get it on my first bike and it's not a pleasant experience at all! When I upgraded my wheels I found that it all but stopped. So it could be worth getting your bike checked out, make sure everything is tightened, wheels are true etc. etc.

There are some things you can try to do when it happens. It seems counter-intuitive, but try to stay relaxed, don't grip the bars tightly, and keep your arms bent. Also, try to hold your knee against the top tube, this helps dampen the vibrations and used to help me when I got the wobbles.

mamba80

try 90/95 psi, at your weight, with those pressures, you ll be bouncing over the road surface, headset bearing adjustment/lube.
DA 9000 are top end so should be absolutely fine, you could try a different set of tires, say PRO3s as they are dirt cheap at mo, so wouldnt cost much to try.
weight distribution - ie experiment with saddle fore aft and stem length. saddle/bar drop, get lower when at speed, only needs to be very slight adjustment.
Relax when you ride, dont grip the bars too much, might be difficult if you think your about to crash though.

sungod

there're several threads on the subject, these should help...

viewtopic.php?f=40020&t=12915040&hilit=wobble
viewtopic.php?f=40013&t=12877040&hilit=wobble

Mr Will

Relax.

Seriously, the wobble kicks in when you tense up and gets worse the harder you try to correct it. Go soft and let the bike sort itself out, it will do - I promise :-)

Daz555

Never had a speed wobble on a road bike. Looking at your pressures though I'm surprised you are running at 110psi when only 72kg - could this be making your bike skip about too much? I run about 90psi and I'm about 15kg heavier than you. Not had any pinch flats to date.

desweller

Check your wheels for lateral true and runout. Then give each one a good spin in turn and check that they don't make the frame hop or wobble (best done with the bike upended). Then there's your headset; make sure that's all locked up correctly, no knocking etc.

Tyre pressures seem pretty high for your weight as the others have said.

smoggysteve

To anyone who has ever ridden motorbikes, they will tell you speed wobble has nothing to do with wheel trueness, pressure or weight. Any of them things can maybe once contribute but are not the cause. I have had speed wobble doing 165mph on my Suzuki and that's scary. Only thing you can do to stop it is blip the accelerator. Similarly on a road bike all you can do is ride it out. Do not brake FFS!! It's still a phenomena why it happens. Don't go thinking its something wrong with you bike or wheels. Can happen and has happened to the pros on steep descents with a bike so finely tuned.

Monty Dog

Not uncommon and main cause is a harmonic vibration in the whole bike system of bike, wheels, rider and even road surface. I had it with an old Alan Carbonio and swapping the alloy fork to carbon got rid of it after a scary moment descending the Wicklow Gap in the pouring rain. In this case I'd suggest fitting wider, 25mm tyres and running them at a lower pressure which will effectively 'dampen' any vibration that sets up the harmonic.