How dangerous is this?

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04-04-18 | 06:11 AM

#26

martl

Strong Walker

Joined: May 2007

Posts: 1,404

Likes: 616

From: Black Forest, Germany

Bikes: too many

Quote:

Originally Posted by tarsi

The fork does have a hole in the back it's just not large enough for the recessed nut to fit. Some have suggested drilling the hole larger and using a longer recessed nut. I prefer not altering the fork.

The brake set I'm using is recessed. I'm actually using the rear brake up front as it was too short for the back. Neither the rear nor the front brakes are long enough for the front.

I'm leaning towards the coupler solution vs disassembling the brake and replacing mounting screw with a longer one assuming it will be sufficiently strong to support the forces. Mechanical engineers?

I am one... i'd go look for a bolt of the correct length. A proper bolt with a rolled-on thread, that is. Not some piece of some-steel rod onto which a friendly buddy has cut a thread on. There *are* some serious forces on that thing.

Picture this: When applying the brake, the bolt is bent upwards in a radius. That radius is far smaller if the bolt is only attached to the front plate of the fork crown.
Now, there is nothing a bolt with a thread (=row of notches) hates more than being bent (notch effect).

And a failing front brake bolt is about the ugliest thing that can happen on a bike. Caliper will travel with the rim, as it is still applied by the bowden. When it has rund out of cable length, it will go sideways, jamming the wheel by gripping a spoke and colliding with the fork. I've seen it happen. Instant nose dive with no hope in hell to even bring the arms forward.

Last edited by martl; 04-04-18 at 06:21 AM.