Unstable bike

[Cheese]

Hi ,

i found recently and again in Argus that my bike goes unstable at high speeds 60+.

 

It is as if is getting a speed wobble , got it just before Wynberg hill, but not again.

Anybody with similar experiences, I have checked but can not find anything wrong, felt like at started at the back.

[Gravity]

put your hands on the handlebar at those speeds.

[MaxUmis]

Most likely the resonant frequency of your bike.

 

You could check the play on your wheel bearings and perhaps have the wheels trued.

 

My old Trek used to go "wobbly" at about 75km/h... Made for interesting descents

[Eldron]

Check:

 

Loose/tight headset.

Loose front QR or axle.

 

Sometimes bikes just seem to have a resonant frequency that causes the olde wobble as the other poster said - try changing the front tyre. That cures it sometimes...

[andretraut]

My Spez S-Works gets a wobble if I exceed 100km, so to avoid it, I just stay clear of that speed!

[Guest Iron]

I had this a one bike years back and we did all the checks, headset , changed wheels , changed tyres, ect... still did the same thing. Then we changed my position on the bike completely , shorter stem and moved the saddle forward and presto wobble gone .

 

Im not saying this will work for you but if you try all other options and still rattle at speed , try this.

[Christopher Brunsdon]

Most likely the resonant frequency of your bike.

 

You could check the play on your wheel bearings and perhaps have the wheels trued.

 

My old Trek used to go "wobbly" at about 75km/h... Made for interesting descents

 

That sounds like a call for the POWERBALANCE bike bracelet to restore the frequency of your ride ... call now and we will throw in a bottle of snake oil lube absolutely free

[LeTurbo]

I'm with Eldron. If it's the bike's resonance, try gripping the crossbar with your kneees and see if that kills it. Getting your bum off the saddle also helps. I've one bike that gets a speed shimmy down Suikerbossie, but nowhere else - and my other bikes are fine on that same stretch. A slightly loose headset makers your whole bike feel twitchy and unsettled.

[Tiny K]

My Spez S-Works gets a wobble if I exceed 100km, so to avoid it, I just stay clear of that speed!

 

Sure it's not just the legs? LOL

[Spark]

I agree with Iron. If it is not a mech problem, then most likely your reach is too long. Had the same problem

[TNT1]

Hi ,

i found recently and again in Argus that my bike goes unstable at high speeds 60+.

 

 

 

Slow down?

[Brakkies Sport Fotos]

I guess you got carbon handlebars?

 

Next time just close your kness against the top tube (at the downhill speed) and it wont happened.

[Shebeen]

been brought up here before, and there's an article here http://www.sheldonbrown.com/gloss_sa-o.html#shimmy

 

if you want to read a classic who has the better pocket protector episode, here is one on the subject starring The Break and the inevitable JB. I can't not mention that it was started by a bona fide gayboy

My link

[Darryl O]

Here is a bike review that I have just read that reminded me of your problem.

 

http://ftptraining.wordpress.com/2010/09/

 

Does not tell you how to fix it though... sorry.