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Framebuilders Thinking about a custom frame? Lugged vs Fillet Brazed. Different Frame materials? Newvex or Pacenti Lugs? why get a custom Road, Mountain, or Track Frame? Got a question about framebuilding? Lets discuss framebuilding at it's finest.

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Old 08-29-10, 06:28 PM   #1
ColinT
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First Fork Woes.

Hi all. So I just built my first cyclocross fork with canti mounts and when braking Im getting some violent brake shudder. It is lugged with a 1" steer tube and 38mm of offset that was media blasted and powder coated. Im pretty fresh when it comes to building forks so I was wondering if there are some common rules I may have over looked or a possible quick fix to remedy it. I have tried different brakes, pads and different wheels. I have toed the pads to the max and that helped a bit but now Im stumped to what to do next.

Thanks Colin T.
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Old 08-29-10, 08:57 PM   #2
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you might try a crown mounted cable stop. Also, many cross riders cut down their front brake pads.
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Old 08-30-10, 05:43 AM   #3
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I experienced braking shudder recently and it was because of a too low mech. advantage on my cantis. Don't know if that will help, but you can try lowering the yoke and make sure you have the proper levers...
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Old 08-30-10, 07:52 AM   #4
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Thanks for the replys. I have gone though all the normal fixes of canti shudder. Run the carrier high and low, mounted the cable stop on the fork, headtube and stem, running canti brakes with road drop levers, tried different pads, rim widths and toe. So that is why I am thinking it is a manufacture problem on my part. Could it be a low offset issue? I know most canti forks run in the 45mm area and Im running a bit less than that. I have been a bike mechanic for many years now but a frame builder for much less so I think that is where maybe I am not seeing something.
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Old 08-30-10, 08:25 AM   #5
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Hmm I'll throw a wild guess here, but perhaps the fork is too stiff? Do you have straight blades and a sloping crown? I think shudder occurs when the fork flexes near the crown or bosses during braking, thus tightening the cable below the stop. I'd say with curved or longer blades, chances are the flex will occur below the bosses?
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Old 08-30-10, 09:10 AM   #6
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I am not sure how misalignment affects cantis, could be the problem. I can't imagine a fork being too stiff would be a problem, a wimpy fork is a known problem.
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Old 08-30-10, 09:12 AM   #7
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Quote:
Originally Posted by tuz View Post
Hmm I'll throw a wild guess here, but perhaps the fork is too stiff? Do you have straight blades and a sloping crown? I think shudder occurs when the fork flexes near the crown or bosses during braking, thus tightening the cable below the stop. I'd say with curved or longer blades, chances are the flex will occur below the bosses?
Hmmm.... Could be. My Gunnar Crosshairs had horrendous shudder with Shimano BR550's. 1 1/8" steerer, cast full-sloping crown and curved blades. My Kogswell P/R has no trace of shudder: 1 1/8" steerer, cast flat top crown, and LOOOOONG curved blades (like enough vertical clearance for 50mm tires and fenders!). So maybe the flex is better distributed in the P/R fork?

SP
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Old 08-30-10, 12:25 PM   #8
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Try the fork on a different frame.
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