Fixed Wheel Speed Wobble

sskelly

Hello All,

I have been riding a fixed wheel for over a year now mostly on the flat. I have just started using it for more of a training machine rather than a commuting bike.

On some down hills I have noticed that the rear wheel feels like it is sliding away and occasionally I experience speed wobble. It is very unnerving and today I thought I was going to come off!!

I have a front and back brake and tend to use both down hills. Any advice greatfully appreciated.

Simon

majormantra

Is it possible you're locking up the rear wheel? Try using only the front brake. Also, shift your weight back in the saddle as much as possible. You want as much weight over the rear wheel as possible.

I've found that at very high rpms (160-185 or so) I sometimes start bouncing on the saddle slightly but I don't think that's what you're describing. One way to reduce this is to lower the saddle a few mm.

Matthew

mgcycleguy

Is your rear wheel straight... I've noticed with horizontal dropouts its possible when trying to get your chain tension correct you can get your rear wheel out of line...

sskelly

I have had a good look at the bike tonight and trued the wheel (it was not too bad), tensioned the spoke a little and corrected the brake caliper position (it was pulling the rim slightly one way).

I have however noticed that there is some paint flaking around one of the welds - could this indicate a problem with the frame?

FixedNewbie

Hey,

I know exactly what you mean!

I dont know the cause as such, it usually happens to me when going down hill and trying to slow down but my best guess is that it is my feet not quite matching the rpm that i should be doing, i think the slight back pressure(maybe from just one foot) causes it to dance. Ive always been able to sort this with the rear brake though. Its a scary feeling because it feels like the bike is just going to spit you off!!

No solid answer to reason but the right application of rear brake should get it back inline.

sskelly

I guess this poses the question "how do you cycle down hill correctly on a fixed wheel".

Any takers?

Si

tatanab

sskelly wrote:

I guess this poses the question "how do you cycle down hill correctly on a fixed wheel".

What is correctly? The object of the exercise is surely to get to the bottom, under control, at a pace that suits you.

I've been riding fixed for 40 something years and every day and every hill is different. Once in a while 200rpm feels fine (very, very seldom), other times 150 is dodgy (perhaps the surface is broken up). Above say 150 rpm I find I feel leg braking is not effective. I do not use a rear brake, only a front one. So I suppose the correct answer is that there is no correct way.

sskelly

tatanab wrote:

What is correctly? The object of the exercise is surely to get to the bottom, under control, at a pace that suits you.

What I meant was what is other people's technique for riding downhill on a fixed. Do they peddle hard so that you are still forcing the bike, do you ease off so that the pedals are driving your legs, do you use a brake, use your legs to brake....

Si