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Old 07-28-11, 03:25 PM   #1
jcharles00
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new cranks don't clear chain stay. what to do?

I recently bought a used landshark steel track frame. It came with some rigged up road cranks, that didn't clear the chainstay when I installed them. rather than screw around with them, I bit the bullet and ordered a new set of sram omniums. I just installed them, and they don't clear the chainstay either! It's not by much, just on the end of the cranks 5 "spokes" where the bolts go through.

so.. should I put a dimple in the frame so it clears, file down the cranks, or put a spacer in and try to adjust my chainline accordingly?
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Old 07-28-11, 04:45 PM   #2
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First verify that the frame is straight. If the rear triangle is bent to the right, that might be enough to cause contact. The classic test is to run a string from one dropout around the head tube and back to the other dropout, then check the distance of each run of string from the seat tube.

So how does a track frame get bent in that direction? Easy--most falls are on the right side, and once down the next guy rides right over the back of the faller's frame with the fallen rider's right leg trapped beneath.

If bent, as it's steel, it's no big deal to have it realigned.

If it's straight, then dimple it as gently as you can. I've used the ball side of a ball peen hammer as the drift. (hold the hammer in place and tap with another hammer) Don't just whack it in one spot--move up and down the chainstay so your dimple doesn't become a crimp.
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Old 07-28-11, 05:12 PM   #3
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Cut the chainstay, of course.
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Old 07-28-11, 05:34 PM   #4
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Sounds like you need a longer BB spindle.
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Old 07-28-11, 06:39 PM   #5
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Originally Posted by shadoman View Post
Sounds like you need a longer BB spindle.
Omnium cranks, outboard bearings with a fixed spindle length, so there is no way to increase the spindle length.

I've had this same issue, as have many others on these cranks on a variety of frames.

I fixed it in 2 ways:

1) As nice as the omnium cranks are, ditch them and get something with a square taper where you can buy a longer spindle on the bb, 110 or 112mm.

2) Glue the backs of the chainring bolts into the crank arms, which if you race a lot you tend to do anyway to make ring changes easier. Then hello Mr Dremel tool. Grind the backs of the chainring bolt fittings on the crank arms a little to get the clearance that you need.

Pretty no, but it works.

Personally I wouldn't be hitting the frame with a hammer, but that's just me.
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Old 08-02-11, 12:30 PM   #6
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Thanks for the advice everyone. I ended up going with sideshow_bob's advice and epoxied the backs of the chain ring bolts into the spider and then hit the backs of the spider arms with an angle grinder until everything fit.
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Old 08-02-11, 01:21 PM   #7
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Heard SRAM was working on a new version of these cranks. Hope if it's true they fix the problem of not fitting a lot of frames.
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Old 08-03-11, 08:38 AM   #8
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Heard SRAM was working on a new version of these cranks. Hope if it's true they fix the problem of not fitting a lot of frames.
I saw in another post that people were anticipating a debut of the new version in September. I'm no mechanical engineer, but it seems like the extra material on the spider isn't really helping stiffness in the axis that force is applied, so it would make sense to remove a little to suit wider application.
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