Troubleshooting front wheel / fork vibrations when braking

f_rederik

Hi all

My 29er hardtail has developed a problem where there is quite a lot of vertical movements / vibrations in the (rigid) fork during front wheel braking. I have hydraulic disc brakes.

It is worse when I first start riding - it seems to reduce after 5-10k however the vibration is still very noticable.

Bike was built by a friend from China carbon frameset + assorted component, and has been ridden about 5000k without problems, and I have recently changed the brake pads to no avail.

Would it make sense that it is about time to change the headset, and that this could fix the problem?

Cheers
Fred

nicklouse

if it needs changeing then maybe. does it?

work your way through and see what is actually moving.

it may be a fork/frame failure or it might just be something that needs adjusting rather than replacing.

The Rookie

Have a look at the brake disc, if the pads are overlapping the inner or outer edges of the braking surface too much then that can cause a vibration as the pads come into contact with the sticky out bits (like the web holding the braking surface to the hub for example).

lpretro1

Assume you have checked for play in headset?

f_rederik

There is a bit of travel when applying the front brake and 'rocking' the bike forward.

Sorry to be a plum but that means there is play in the headset, right?

Chunkers1980

No. It could be, but it could also be he rotor, pads or calliper too. And/or fork bushes

The Rookie

Put a finger sideways across the joint between headset/frame and fork (so you can feel both sides) pull on the brake and then rock the bike backward and forwards, can you feel movement across the headset?

f_rederik

[url=http://www.bikeradar.com/forums/viewtopic.php?p=19653136#p19653136]The Rookie[/url] wrote:

Put a finger sideways across the joint between headset/frame and fork (so you can feel both sides) pull on the brake and then rock the bike backward and forwards, can you feel movement across the headset?

Yep - there is movement. Guess I'll be taking it to the workshop to have it looked at professionally

Thanks for your assistance folks

cooldad

If there's a bit of movement probably just means the headset needs tightening. 5 minute job. Read Parktools.