G
Glenn Ammons
Guest
I recently bought (and bent, see below) a used Miyata 912 frame. If I insert a rear wheel so that it
is centered between the chain stays, the wheel is off-center about 5mm at the brake bridge. The
string test tells me that the rear triangle is properly centered, and I've used the Park tools to
check that the dropouts are parallel. The seat tube appears to line up with the head tube, but I'm
judging by eye.
My theory is that the dropouts are both bent by the same amount, so that the wheel sits
cockeyed. Before I start wrenching on them, does this theory make sense? Is there anything I
should check first?
Full disclosure: I could have caused this problem myself. When I got this frame, the rear spacing
was 130mm. I think that it was originally 126mm and inexpertly spread to 130mm, because the rear
triangle wasn't centered. It seemed like someone had just bent the right side of the triangle out
4mm while leaving the left side in place. Since I wanted 126mm spacing anyway, I bent the right side
of the triangle back 4mm. After that, the string test checked out, the wheel sat centered in the
chain stays, and the dropouts were parallel. The only bugaboo is at the brake bridge.
Thanks. --glenn
is centered between the chain stays, the wheel is off-center about 5mm at the brake bridge. The
string test tells me that the rear triangle is properly centered, and I've used the Park tools to
check that the dropouts are parallel. The seat tube appears to line up with the head tube, but I'm
judging by eye.
My theory is that the dropouts are both bent by the same amount, so that the wheel sits
cockeyed. Before I start wrenching on them, does this theory make sense? Is there anything I
should check first?
Full disclosure: I could have caused this problem myself. When I got this frame, the rear spacing
was 130mm. I think that it was originally 126mm and inexpertly spread to 130mm, because the rear
triangle wasn't centered. It seemed like someone had just bent the right side of the triangle out
4mm while leaving the left side in place. Since I wanted 126mm spacing anyway, I bent the right side
of the triangle back 4mm. After that, the string test checked out, the wheel sat centered in the
chain stays, and the dropouts were parallel. The only bugaboo is at the brake bridge.
Thanks. --glenn