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Discussion Starter · #1 ·
I'm swapping components over to a larger MTB frame but the old BB thats with the components is too short and the old one in the larger frame lets the inner chain ring hit the chain stay. The components are a mix of Shimano Exage Country and Exage Trail. The crank says Country. Any help would be great since I'm trying to get this bike back on the road ASAP.
 

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Militant commuter
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How much does the ring need to move out to clear the chainstay? When you go "off the books" like this, sometimes trial and error is the only way to determine the best length. Obviously, unless you have a variety of BB spindles laying around, this could be expensive.
 

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Discussion Starter · #3 ·
SilverStar said:
How much does the ring need to move out to clear the chainstay? When you go "off the books" like this, sometimes trial and error is the only way to determine the best length. Obviously, unless you have a variety of BB spindles laying around, this could be expensive.
I would say 3/16" to 1/4". It looked like the crank arm was just seating when the chain ring started to hit the chain stay because I had to use the extractor and give it a little nudge. The too short BB that came out was a Shimano BB-UN50.
 

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High Gear said:
I would say 3/16" to 1/4". It looked like the crank arm was just seating when the chain ring started to hit the chain stay because I had to use the extractor and give it a little nudge. The too short BB that came out was a Shimano BB-UN50.

do you know how long the spindle was on the UN50? Since this a mtn style crank, I'd start with 118mm-122mm...Just a guess...
 

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Discussion Starter · #5 ·
Dave Hickey said:
do you know how long the spindle was on the UN50? Since this a mtn style crank, I'd start with 118mm-122mm...Just a guess...
It does not say on the BB. How is this measured? From end to end? It is 4.812" or 122mm end to end.
 

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If the current BB spindle is already 122 mm (and yes, it's measured end-to-end), you're into some "trouble territory". Slightly longer spindles are available (125 or so?), but for much longer (130mm range) the only company I know of that makes 'em is Phil Wood. And that's not a cheap prospect...
 

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Discussion Starter · #7 ·
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SilverStar said:
If the current BB spindle is already 122 mm (and yes, it's measured end-to-end), you're into some "trouble territory". Slightly longer spindles are available (125 or so?), but for much longer (130mm range) the only company I know of that makes 'em is Phil Wood. And that's not a cheap prospect...
After looking on the web, You are right. I think I am SOL and will have to find another crank set. This Shimano Exage country/Trail will not work with this frame. The frame I'm building is a 1993 Giant ATX-760. From what I see, it came with Shimano Exage LT.

If anyone has a used Shimano 7 speed crankset they want to sell please PM me. I would like to get this bike back together so that I can tow my kids around in the trailer.
 
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