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bike tester
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Discussion Starter · #1 ·
I only had external bb's so far... now i picked up a set of race face ride xc isis crank arms on ebay and i have no idea what bb i can use. i know the frame needs a 68mm shell, but do i have to use 113 mm spindle length or can i go a little longer? i found a 118 mm american classic bb (supposed to be really light), can i use that one?

thanks
 

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Probably not.

You need a 113mm, a 118mm would most likely place place the biggest chainring too far outboard to be usable in most of the cassette range.
 

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Former Bike Wrench
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standard3x said:
Probably not.

You need a 113mm, a 118mm would most likely place place the biggest chainring too far outboard to be usable in most of the cassette range.
Not Correct:

113mm BB spindle will be a 47.5mm chainline, the older standard

118mm BB spindle will be a 50mm chainline, the current standard for outboard bearing BB's

Either will work fine, just need to adjust the front dérailleur accordingly.
 

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Any minute now, the penny will drop.

Notice that the OP asked about the Ride XC - three rings. Ride DH is 2 rings and bash, so makes sense to use a 118mm.

Chainline on the 113mm would be about 48mm to 49mm, assuming that half a millimeter of bb shell material has been shaved off each side due to facing as the bike was originally fitted with external bb cups. Otherwise, it would be about 48.5mm to 49.5mm.
 

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Former Bike Wrench
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standard3x said:
Any minute now, the penny will drop.

Notice that the OP asked about the Ride XC - three rings. Ride DH is 2 rings and bash, so makes sense to use a 118mm.

Chainline on the 113mm would be about 48mm to 49mm, assuming that half a millimeter of bb shell material has been shaved off each side due to facing as the bike was originally fitted with external bb cups. Otherwise, it would be about 48.5mm to 49.5mm.
Again, this is not correct

Three ring crankset will work fine on a 118mm spindle, some frames even required this length because of either a large diameter seatube that interfered with the front derailleur or pivot/swingarm interference.

When measured as per the "Shimano" method (as illustrated on Sheldon Brown) a ISIS 113mm BB spindle will result in a 47.5mm chainline and a 118mm BB spindle will result in a 50mm chainline. Both of which will work just fine with a triple crankset.

Have fun waiting for that penny to drop...in fact hold your breath while your waiting:skep:
 
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