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Old 11-15-04, 10:49 AM   #1
Rambo
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I recently bought a raleigh m80. I don't like the gearing so I bought new cranks.

it had Shimano Deore 44x32x22 cranks.

I bought Nashbar ISIS Trekking Crankset 48/38/28
http://www.nashbar.com/profile.cfm?c...eid=&pagename=

had to get a new BB (ISIS) and a Shimano XTR FD (to handle the larger chain rings)

I'm still at work, looking at the parts that came in the mail and one thing strikes me funny. The center of the cranks is set in farther than the old cranks. It appears to me that its going to rub on the frame.

I did pick out the new cranks from the "road cranks" on the nashbar site. Was this a mistake? Are they made different?
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Old 11-15-04, 11:32 AM   #2
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The crankset determines what bottom bracket spindle length you need. Some cranks require a longer spindle than others.
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Old 11-15-04, 11:47 AM   #3
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ok, so there is no difference between road cranks and mtb cranks other than the obvious gearing and amount of chianrings of course?

Theoretically I could put road cranks on a MTB then?

the cranks call for 113 or 118mm. the bike had 110mm bb so I figured I'd go with the 113. I know it was a shot in the dark and considering I had a 50/50 chance to get it right I knew I'd order the wrong one first.


worst case I'd have to get the 118mm bb then?
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Old 11-15-04, 12:51 PM   #4
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Quote:
Originally Posted by Rambo
ok, so there is no difference between road cranks and mtb cranks other than the obvious gearing and amount of chianrings of course?

Theoretically I could put road cranks on a MTB then?

the cranks call for 113 or 118mm. the bike had 110mm bb so I figured I'd go with the 113. I know it was a shot in the dark and considering I had a 50/50 chance to get it right I knew I'd order the wrong one first.


worst case I'd have to get the 118mm bb then?
Sometimes road cranks interfeer with chain stays on MTB frames. A fat downtube would suggest the use of a 118 spindle length.
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Old 11-15-04, 05:40 PM   #5
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Quote:
Originally Posted by Rambo
ok, so there is no difference between road cranks and mtb cranks other than the obvious gearing and amount of chianrings of course?

Theoretically I could put road cranks on a MTB then?

the cranks call for 113 or 118mm. the bike had 110mm bb so I figured I'd go with the 113. I know it was a shot in the dark and considering I had a 50/50 chance to get it right I knew I'd order the wrong one first.


worst case I'd have to get the 118mm bb then?
Actually, the rear dropout spacing makes the determination between 113 and 118mm. If your rear dropout spacing is 130mm, you need the 113. If your rear dropout spacing is 135mm, you need the 118. The smallest cassette cog is always the same distance from the right dropout so, if you have a wider rear triangle, you need a longer bottom bracket spindle in order to get the correct chainline.
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Old 11-15-04, 07:07 PM   #6
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Actually, the rear dropout spacing makes the determination between 113 and 118mm. If your rear dropout spacing is 130mm, you need the 113. If your rear dropout spacing is 135mm, you need the 118. The smallest cassette cog is always the same distance from the right dropout so, if you have a wider rear triangle, you need a longer bottom bracket spindle in order to get the correct chainline.
Current mtb are 135 dropout spacing,so the seattube diameter becomes the default for picking the spindle length.Some frames may aslo require the longer for chainstay clearance.

Last edited by sydney; 11-15-04 at 07:14 PM.
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Old 11-15-04, 07:40 PM   #7
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turns out the 113mm worked fine. thanks for the help guys.
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