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Discussion Starter · #1 ·
Mild braking==> ok

Very hard braking on a steep downhill ==> ok

Moderate braking ===> chatter, no perceived brake steer, but very disconcerting stuttering. Fork can be observed flexing forward and back in phase with the felt and heard chatter.

This is with 1.25" x 0.035" x 16.75" long "rigid" fork blades and a 250 lb rider. A 160 lb rider can not reproduce the problem.

thoughts? suggestions?

Richard
 

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Discussion Starter · #3 ·
Clockwork Bikes said:
What kind of brakes? Cantis? Is the cable stop in the headset stack or stem?

-Joel
Sorry, critical info missing... 203mm Avid disc. Continuous housing, run to a clip on the front of the left fork leg and then up to the lever with a bit of slack to spare.
 

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rocwandrer said:
This is with 1.25" x 0.035" x 16.75" long "rigid" fork blades and a 250 lb rider. A 160 lb rider can not reproduce the problem.

thoughts? suggestions?
Yep that's too light a fork for a 250lb. rider. A fork like that would be fine up to about 190-200 I would think. Had it been designed for a thru-axle that would help a bit, maybe. You're just asking the fork to work too much particularly with a 203 rotor, maybe try a 180.
 

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rocwandrer said:
Mild braking==> ok

Very hard braking on a steep downhill ==> ok

Moderate braking ===> chatter, no perceived brake steer, but very disconcerting stuttering. Fork can be observed flexing forward and back in phase with the felt and heard chatter.

This is with 1.25" x 0.035" x 16.75" long "rigid" fork blades and a 250 lb rider. A 160 lb rider can not reproduce the problem.

thoughts? suggestions?

Richard
Here is your chance to correct the offset with a new beefier fork.
 

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Discussion Starter · #9 ·
The hub is a DMR revolver bolt on with 6 mm hex bolts torqued down tight.

The frame has a long head tube with big tubes and is overall a very stiff design. the fork is as mentioned earlier 1.25" dia x 0.035" wall legs with a 10" long butted 2.1-1.6 1.125" steerer. seems like the fork just isn't stiff enough....

the fork is clearly strong enough but apparently just not stiff enough. The fork is unpainted, and would be easy to modify. Anybody had success with tricks for beefing it up short of a Jones style truss?

What do people like for fork legs for a 275 lb rider (only dealing with 250 lb, but i don't want to push it, given I am fixing a problem that is already there)?

Is there an elegant easy or OTS solution for the drop outs? The present fork is unicrown with plug in dropouts, which is easy as can be, presents no hard edges to the falling rider in a crash, and is an "elegant solution" to my eye (I know others here feel very differently).
 

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Discussion Starter · #10 ·
shiggy said:
Here is your chance to correct the offset with a new beefier fork.
yup. I was just a little gun shy to jump to that conclusion after being convinced, but having it wrong on the handling issue which really everybody with this tire and rim combo has (and bonus, isn't an issue at all on snow, even on hard packed/icy).

I'm no weight weenie, but this bike is already a bit on the portly side of easy to carry up the stairs to my office at work, so I'm not looking to use 1.75" x 0.035" fork blades if I don't have to....
 
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