Sunday, September 20, 2009

Kuwahara Fork Problem

I've suspected that my Kuwahara fork is bent, and I figured out a way to prove it tonight. I put the fork, forward-facing up on a board, and pushed the drop out end of the fork and the fork side up against a board I placed square to the side of the board on which it's laying.

I then drew a line on the board on which the fork is laying, extending the line from the side of the head tube. I then pushed the fork over to the other side of the board like I did above. I extended the line from the side of the head tube again. It is now easy to see I have a problem. No wonder the bike wanted to pull severely to the right.

The right side of the fork is bent inward and slightly backward.

I placed tape on the fork where it bends inward.

This camera angle shows how the right side is also bent backward.
This photo doesn't show it very well, but the right drop out is also very slightly twisted. Notice the two holes for bolts on each drop out. I assume the front side is for a bike rack, and the back side is for fenders.

I don't have a vise for my workbench, but I plan to bolt the fork directly to the workbench and use something, maybe a bar or a piece of galvanized pipe to bend the right side back to where it needs to be. As Jon, of Two Wheels has said, I'll need to have the drop outs twisted back to parallel.


Steve A said...

Now you know what you're dealing with. I have confidence you'll be able to correct the problem.

Chandra said...

Nice systematic approach to finding the problem! I like your approach!!
Peace :)