Fork chatter with a mini-v brake?!

Especially for light weight issues concerning cyclocross / touring bikes & parts.

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CrossRob
Posts: 63
Joined: Tue Dec 14, 2010 9:18 pm

by CrossRob

I've switched fork on my cross bike from a Cannondale Slice to an Easton EC90X, saving about 300g.

I used to have a fork crown mounted brake hanger to avoid chatter, but you can't fit one of these on the Easton, so I've switched the front brake to a Tektro 926 mini-v.

How then do I still have brake chatter?

I'm using Kool-stop salmon and black pads on Ultegra alloy rims (both pads and rims are clean). I've tried with no toe-in (squealed painfully) and with 2mm toe-in, which was much quieter, but still shuddered stopping quickly or downhill.

The boss bolts are tightened and there's no obvious forward/back play in the v-brakes.

This is driving me nuts. What am I missing?!

by Weenie


gmitt98
Posts: 57
Joined: Thu Apr 05, 2012 6:49 pm

by gmitt98

Try switching pads? It sounds like they might be a little bit grabby. Something softer maybe?

dwb
Posts: 35
Joined: Wed Feb 15, 2012 7:11 am

by dwb

Wow, chatter was supposed to be impossible with v-brakes. Easton forks shudder worse than other forks, but only with cantis. It is not an obvious mechanism causing the shudder. I use an older version of the 926. The bike has no shudder, but will squeal unless toed in.

If you have tried both salmon and black pads and it still shudders, have you tried it with another wheel? How is the brake track of your Ultegra wheel? I notice that some rims are more grabby than others, but I cannot get my bike to shudder, the back wheel will lift up first.

elSid
Posts: 219
Joined: Sun Aug 02, 2009 6:59 pm

by elSid

I've given up trying to eliminate shudder from my Easton EC90X fork w/ TRP miniV. Carefully setting toe-in has helped, but I'm going to get another fork soon.

Changing wheels didn't make any difference.

CrossRob
Posts: 63
Joined: Tue Dec 14, 2010 9:18 pm

by CrossRob

Thanks for the comments.

It's an almost new wheel, so the rim is perfect. I'll try putting an older wheel in there for a comparison.

Pads are something I'll try too. I read somewhere yesterday that shorter pads might be better than the long v-brake ones.

The other suspect is my inline cable adjuster. I wonder if there's some compression in the cable housing going on there.

Grateful for any more suggestions in the meantime. I'd really prefer not to lose the fork though!

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simon
Resident Pro
Posts: 1784
Joined: Mon Apr 18, 2005 9:34 am

by simon

all easton forks(at least all the 1 1/8 steerer ones i've ridden, that's ec90 aero 2006-2010, ec90 slx 2009, ec90 sl 2008 and ec90 x probably 2008)are noodels, the steerer is really not stiff wich makes it hard to make the bike go into the direction you want in corners on and off road. a soft fork does not help when you want to avoid brake chatter(just braking is also bending the fork. in the contrary direction than cable pull, but it starts somewhere).
while this may not sound logical, the switch to stevens cross forks on last years bmc bikes was mind blowing. try to sell it and get a better fork(there are within maybe 50 grams of the easton), the performance gain will outweight any weight penalty!

mjduct
Posts: 662
Joined: Tue Dec 27, 2011 2:19 pm

by mjduct

simon wrote:all easton forks are noodels,


I've used some of their lighter models with the same result. great for soaking up road vibration, and great for showing your friends just how light a bike you can build, bad at just about everything else...

brusko
Posts: 5
Joined: Wed Jun 27, 2012 8:40 am

by brusko

Try adding more toe-in. Do update us.

CrossRob
Posts: 63
Joined: Tue Dec 14, 2010 9:18 pm

by CrossRob

Relief!

I switched the brake pipe and separate barrel adjuster for a flexible pipe with built in adjuster. There must have been some compression somewhere along the line as it's now pretty much sorted out.

I can still get some shudder if I brake hard with my weight forward, but riding a bit more smoothly, it's fine.

The fork is definitely more flexible than the Cannondale - you can see it moving forward and back under firm braking - but at least it's now controllable.

Thanks for everyone's input.

by Weenie


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