CX fork vibration when braking

[mdeeds71]

My Bedford CX has an enve cx fork installed with TRP RevoX brakes.

No matter how I toe them or align the pads I get a vibration/chatter.

I can feel a very small bit of slop (rocking) on the brakes icw the posts when I move them via the brake arms. I can confirm the screws are fully installed into the bosses and there is not lateral movement along the axis of the brake bosses. The rear are a bit more solid…but I do not know if that small fractional amount would cause the chatter. I can see it in the fork arms/hub area when I am braking.

Ideas?

[veggieburger]

I had a similar issue. Turns out there was play inside of the Tektro brake sleeves, where the brake bolt was installed. No matter how tight I wrenched down the bolts, braking caused front end shudder. Disassemble the entire mess and check.

[joosttx]

My Bedford CX has an enve cx fork installed with TRP RevoX brakes.

No matter how I toe them or align the pads I get a vibration/chatter.

I can feel a very small bit of slop (rocking) on the brakes icw the posts when I move them via the brake arms. I can confirm the screws are fully installed into the bosses and there is not lateral movement along the axis of the brake bosses. The rear are a bit more solid…but I do not know if that small fractional amount would cause the chatter. I can see it in the fork arms/hub area when I am braking.

Ideas?

This is an art more than a science. If you toed ad nauseam, then try lowering the yoke that can help.

[mdeeds71]

This is an art more than a science. If you toed ad nauseam, then try lowering the yoke that can help.

So lower the straddle hanger and then readjust the straddle cable for desired distance?

What is best more or less toe in this case? What amount would you suggest in mm when the toe hits the rim?

[eBAUMANN]

it is very hard to eliminate shudder completely in ANY cantilever setup that DOESNT use a fork mounted hanger.

certain pads work better than others at calming chatter. i have found the "salmon" pads to work the best as they seem to be made of a softer compound than your traditional black pad. if you pads are old, they might be a little dried out as well, which certainly doesn't help.

a longer pad (like a kool stop thin line) can also help, as they can be toe'd in easier and more dramatically than a standard cartridge style pad (like the ones used in trp brakes).

beyond that, not much more that you can do other than keep adjusting until you find that sweet spot.

or just get mini v's and save yourself the time/frustration ;)

[mdeeds71]

it is very hard to eliminate shudder completely in ANY cantilever setup that DOESNT use a fork mounted hanger.

certain pads work better than others at calming chatter. i have found the "salmon" pads to work the best as they seem to be made of a softer compound than your traditional black pad. if you pads are old, they might be a little dried out as well, which certainly doesn't help.

a longer pad (like a kool stop thin line) can also help, as they can be toe'd in easier and more dramatically than a standard cartridge style pad (like the ones used in trp brakes).

beyond that, not much more that you can do other than keep adjusting until you find that sweet spot.

or just get mini v's and save yourself the time/frustration ;)

I put TRP 8.4s on my wife's ride…almost too much brake power…she locks up a bit often.

The TRP pads I have are very adjustable but I have typically left the toe in at a minimal amount…if it should be more then I need to try that as well as lower the hanger.

[joosttx]

So lower the straddle hanger and then readjust the straddle cable for desired distance?

What is best more or less toe in this case? What amount would you suggest in mm when the toe hits the rim?

I think you are approaching the wrong way. As I said its an art more than a science, you are going to have to feel your way into the perfection than measuring into it.

Yes, lower the straddle hanger and adjust the straddle carrier to the desire distance. If your yoke is high it exacerbates chatter. For the toe you'll get a lot of different answers but I typicall leave a credit card width (Chase Sapphire which is a little thicker than you bank's ATM card) when the toe contacts.

FYI I use koolstops thinline brake pads

[Admiral Ackbar]

in addition to what others have said i would suggest heavily greasing the brake posts.

and make sure the posts don't protrude over the tops of the brakes. I've had bikes where I've had to file a fraction of a mm off the brake posts to get the brakes to stop chattering around on the post because i couldn't get them snugged down

[mdeeds71]

So one other piece of info. When I double check to see how far down the screws go to holding the brake on…the right front bottoms out onto the boss and I can press down on the brake along the axis of the boss towards the fork against the spring compressing/pushing the brake towards the screw and allowing about 2mm of travel.

Should the bosses be flush with the brake or just slightly under the brake lip?

[seanile]

also try scotch brighting/cleaning your rims.. they're probably pretty gunked up with a film of grease and road grit. then take some sandpaper to the face of your pads as they'll have the same problem.

[bcroslin]

My Stevens prestige came with a "problem-solver-canti-noodle-router-thingy" that is amazing and stops chatter and any other type of canti slop. I have no idea if you can buy them but it's worth searching out. It has the traditional router that mounts to your fork but then it has two adjustable little spikes that set against the fork. I've attached a photo for reference.

[oldpotatoe]

My Stevens prestige came with a "problem-solver-canti-noodle-router-thingy" that is amazing and stops chatter and any other type of canti slop. I have no idea if you can buy them but it's worth searching out. It has the traditional router that mounts to your fork but then it has two adjustable little spikes that set against the fork. I've attached a photo for reference.

Vecchio's has them and yes, this reduces this very common thing a lot. Otherwise get mini-Vs...

[eBAUMANN]

My Stevens prestige came with a "problem-solver-canti-noodle-router-thingy" that is amazing and stops chatter and any other type of canti slop. I have no idea if you can buy them but it's worth searching out. It has the traditional router that mounts to your fork but then it has two adjustable little spikes that set against the fork. I've attached a photo for reference.

yes these work but they cannot be attached to enve forks as there is no provided for such a device.

the entire phenomenon (as i understand it) is caused by flex in the fork (which all forks need to have to some extent). The hanger is attached to the steerer at a fixed point above the head tube that does not flex with the fork, so when the fork does flex (from the crown down) it pulls the brake cable tight-loose-tight-loose-tight-etc which creates the shudder. i have no scientific proof of this but in theory it makes sense.

so yea, to come full circle, all you can really do is buy the best/stiffest fork you can (check), some quality brakes/pads/rims, adjust as necessary, and hope for the best!

or buy a fork with a drilled crown and attach a little hangermabob.

or get paul mini motos ;)

[spartanKid]

I've had bikes where I've had to file a fraction of a mm off the brake posts to get the brakes to stop chattering around on the post because i couldn't get them snugged down


Surely a well placed washer would solve this problem too, no?

[bcroslin]

Vecchio's has them and yes, this reduces this very common thing a lot. Otherwise get mini-Vs...

good to know because if I ever sell my Stevens (what am I saying! of course I'll sell it chasing some other bike that I have to have) I'll need another one of those hangers because it's the greatest thing for shudder ever.

[rwsaunders]

Keeping my rims clean, my brake pads clean and going to salmon Kool Stops has worked for me.

[kevinvc]

It's a Bedford CX?

If it's a size 56, you will never be able to stop the brake chatter. Your best bet is to sell it at a loss and move on. I might be willing to take it off your hands as a goodwill gesture. :banana:

[Cat3roadracer]

I noticed this bombing down the hills last weekend in Deerfield. Stay off the brakes, no more chatter.

[mdeeds71]

Vecchio's has them and yes, this reduces this very common thing a lot. Otherwise get mini-Vs...

Would switch to the hanger if the Enve fork had a drilling for it...but not.

As for mini-Vs, just too much force for my liking when I gave them a try...very fine line for modulation vs locking up (TRP 8.4s). To get the modulation I wanted I had to keep the levers pull very long vs how I typically run my brakes.

I will just keep adjusting till I find a sweet spot. I have an idea that will require some machining/creation of a part...but will not be able to get it going till next year...if the fact is to lower the cable stop.