vibrating fork

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Boonen
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by Boonen

Anybody has a solution for a vibrating front fork? It vibrates when I apply the front brake "hard". I have an aluminium 4ZA fork with tektro oryx brakes. I noticed that there is a little space between the brakes and the fork due to some excessive paint on the brakebosses. Would it help when I filed this off so the brakes sit all the way down on the brakeboss? The rearbrake is mounted this way, without paint on the brakebosses but I can still rock the brake from side to side with my hand, which I suspect causes the vibration of the fork on the front.

I noticed on TV that the pro's don't seem to have this problem, so I think there has to be a solution? On the bike I owned before I had the Spooky brakes, but I still had this problem.
What is the trick to prevent this?

Thanks,
Last edited by Boonen on Thu Jul 28, 2005 8:38 am, edited 1 time in total.

by Weenie


homegrown
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by homegrown

I would check your headset first. Many times when you brake hard a loose headset will seem to vibrate like you describe. I can't imagine the brake situation you describe would cause this. Also check your hub. Let us know how it goes.

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Boonen
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by Boonen

Thank you for your advise but I don't think this creates the problem. The bike is new with a new and properly installed FSA headset and a DT-Hugi front hub. I did some research on the internet last night and stumbled over an article by Keith Bontrager. He gives some pointers to correct canti-brake setup that I will try. This requires a new 'joke' and a new cable so I have to pay the LBS a visit before I can try this new setup. I will let you know how it works out.
Last edited by Boonen on Thu Jul 28, 2005 8:39 am, edited 1 time in total.

beavisbnc1
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by beavisbnc1

Boonen

Would it be possible for you to post a link to that Keith Bontrager article you mentioned in the post above.

Trek/VW
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Joined: Wed Mar 17, 2004 8:22 pm

by Trek/VW

Here's one about tuning cantilever brakes at least, don't know if it is the right one:http://www.bontrager.com/keith/rants.asp?id=27.

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Boonen
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by Boonen

Sorry about that, I would have given the link but I appied from my work and couldn't find the site so quick. Trek/WV beat me to it, but this is the article I referred to. I will try the setup he mentions this weekend and will let you know if it works for me.
Last edited by Boonen on Thu Jul 28, 2005 8:39 am, edited 1 time in total.

ger
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Location: holland

by ger

I had the same problem with my Empella with alumina fork. It appeared to be play between the brake bosses and the frogleg brakes.

Oswald
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by Oswald

I have the same problem with my CX bike... Froglegs on alu fork... I also suspected the headset and glued a Dura Ace headset in my frame with locktite... But it just keeps vibrating...

I would like to hear from you if your new setup works, Boonen...

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Boonen
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by Boonen

I did the conversion of my brakes kind of how it is explained in the bontrager article mentioned above and I must say it works pretty good!
The stopping power of the brakes with the standard straddle was good for me. I think the problem with the vibration of the fork was a combination of to much braking power and to little "feeling" with the brake.
First I made sure to set the toe-in on the brakes as mentioned in the article. Using a 0,8 mm steel lip made this pretty easy. This already made a difference as there was no more squeeking but the fork still vibrated.
The next thing I did was replacing the standard straddle-wire with a short piece of braking cable and hanging it to an aluminium weinmann straddle carrier.
In the rear I did something simular as in the top picture. The braking with the rear brake feels pretty much the same as before I chanched the setup, but now front and rear look simular.
In the front I hang the straddle carrier a lot higher making the brake less powerfull but it gave a better feeling with the brake as in the lower picture. (sorry about the pics, but I don't have a digital camera)
I think the vibration in the fork is about 95% less than it was before I changed the front brake. I noticed it gets worse using ceramic rims compared to using normal aluminium rims. Now the only way to make the front fork vibrate is going very slowly and braking hard and abrubt with the front brake, but in normal riding the change solved all my problems.

I hope this helps other people with the same problem, good luck![/img]
Attachments
rear brake.gif
front.gif

by Weenie


seriousconsult
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Joined: Wed Sep 14, 2005 11:48 pm

by seriousconsult

I had a bike that did this. It was annoying as hell.

Screw it and get a new solid fork with shimano br-550 brakes. You'll thank me.

One of the most important things about buying a new bike is not getting a bike with fork chatter. Unfortunately this is common with cross forks.

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