Bicycle Mechanics - So I need to bend my rear triangle back into alignment.

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Yogurt
07-22-08, 11:39 AM
Hello! I've got an older (nice) steel frame that's got a slight alignment issue where both of the rear dropouts need to travel about 3-4mm to the left in order to bring everything back to center. (I measured with a string, there's about 1/8" of an inch difference.)

Exactly how is this done properly? I've called around to a few shops, one even downright refused to try. Thanks!

CharlesC
07-22-08, 12:27 PM
My first bike was found in the neighbor's trash can. It was a 24" wheel fat tire cruiser type bike. Neighbor's dad had backed his car (a Frasier just to date myself a bit) into it. Rear triangle was like your bike's. I laid the stripped frame on it's side and placed the BB on a 4X4 piece of wood. With my little brother sitting on the front of the frame I pushed the two triangles back into line by pushing down with my foot. Took a couple of tries but it went back into perfect alignment.
dit
07-22-08, 12:28 PM
I am no expert but I just finished reading Sheldon Brown's instructions on frame spacing and he has very clear instructions on bending the rear stays. Check out 'frame spacing' and the truth will set you free.

good luck

Malthus
07-22-08, 12:31 PM
It's rather easy actually. Sheldon Brown describes the procedure very well http://www.sheldonbrown.com/frame-spacing.html

Edit: again, I'm too late with my response... Sorry.
MrPhil
07-22-08, 12:40 PM
Ah yes, the good old 2x4. My own technique requires about a five foot length. Clamping the frame in the stand, I hold the board against my chest and pull on the head tube. I pull until I feel a little "give" and measure. Repeat as needed.

I've done the floor method as well. I never felt it was subtle enough. Unless the frame was grossly bent. The I block it up and jump on it!
Yogurt
07-22-08, 01:40 PM
AWESOME. I am feeling adventurous and extremely excited to try this!
Closed Office
07-22-08, 08:05 PM
Just in case people don't realize this, you can check easily if you finally have
everything in alignment. Just get on the bike and get up to speed, and let go
of the handle bars. If you can keep on riding without a problem, everything is
balanced. If you can't first make sure the wheels are lined up properly, and try
again. Being able to ride without hands easily is the quickest test of a balanced
frame.