Have a baffling problem appear recently that I can’t seem to get to the bottom of

Basically when I apply the front brake a really noticeable vibration occurs and you can see the bottom of the fork legs flutter backwards and forwards. Pads are fine and nothing appears to be fouling on anything, so any ideas? It’s driving me mad

It’s a Formula RX by the way

Check your headset and see if that’s nice and tight. If it’s loose the forks will be moving in the head tube and this will cause vibration when braking.

Is your headset slightly loose?

If your headset is fine check for play in the fork – remove the wheel and hold the brace of the lower legs and see if you can move it forwads and back, if so the fork bushes are in need of fettling and this is a job for a pro.

Check your front wheel bearings too, as well as the headset. If there’s play in them, that can cause the forks to judder under breaking

Cheers lads

My new float 150’s do the same after certain sections where a lot of front brake has been used, in my case it’s a well known issue due to Stantion length , I knew this before I purchased the fork, try doing some digging on google and see if like mine it’s a known issue, it canbe caused by vented rotors biting then letting go of the disc , or in simple terms the pad slows the disc then glazes the gets cleaned off by the disc then it does this again and again

Had the same problem with some Hope rotors. Didn’t appear to be fouling but swapping the rotor fixed it. Was fouling the arms of the rotor ever so slightly.

Also worth checking the discs are fitted the correct direction. Also are you running any patterned/wavy discs as sometimes they can cause pulsing from the brakes.

what brand of rotors?

Caliper bolts all tight?

Also check rotor & caliper bolts are tight.

And whilst I’m probably teaching grandma to suck eggs, make sure you undo the stem bolts before re-tightening the headset. I’ve seen someone make that mistake before.

Could it be calliper post mount on the fork is out of alignment? Think I have this problem on my revs – more of a squeal nomally than vibration. Tried some Avid domed washers and problem has gone away. Now need to find somebody who can face the post mounts. Last time I asked the LBS they looked at me blankly, cos they were only able to face a IS mount.

I’ve got a similar issue too… headset is nice and tight, calliper tight and aligned, rotor on tight, rotor on the right way….

when I stand over the bike with my feet on the floor front brake applied hard, put my fingers in between the brace and stantion on the fork, and rock the bike back and forth i can feel a change in pressure on my finger nails… and feel a knock.

was going to see if a service will fix it.

I also get knocking when I lock my brakes on when stationary and its because of the floating rotors.

Basically there’s a tiny bit of play between the centrelock section of the rotor and the braking surface section by the rivets and when the pads are holding the disc, this play becomes noticeable. My LBS tells me this isn’t unusual and not a problem as the braking force in normal use instantly takes up the slack, so doesn’t affect braking performance at all, thankfully 🙂

the leg with the leg attached is knackered on mine and I reckon this is the issue, I can feel the upper moving about inside the lower and its knocking… off to LOCO.

*leg with the brake

Warped disc ?

Bushes in the fork could be gone…

i was thinking bushes… its not teh rotor.

Mine does this…I have two rotors for the front, (different designs, one Shimano, one Hope) and I swap them every few months and it sorts it out til the pads wear and start catching on the rotor again.

+1 for swapping the disc.
I’ve had this several times and swapping the disc cures it. I’m very heavy on the front brake so I think it might be heat/warping related, I’ve just gone to a floating disc to see if that fixes it permanently.

I’ll give it a try but I can feel the stantion moving about.

I had this exact problem 2 weeks ago. The disc is contaminated, making the pads skips when trying to brake. In my case, I used a rag contaminated with furniture polish to dry my bike, including the rotors. I cleaned the rotors with neat Fenwicks then meths, I cleaned the pads with Swarfega. Problem solved.

I had exactly the same problem with my Canyon (Formula RX brakes). Pads were contaminated. Swapped them out for new ones and problem solved.