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Discussion Starter · #1 ·
So I was messing around with my Paragon last night, taking off the 22-32-44 chainrings and putting on some rings that I've borrowed from the shop for sizing purposes.

To my dismay, I have determined that while a 26t inner ring (great for the 29er) fits perfectly, the biggest ring I can fit in the middle chainring position, with adequate clearance (4 or 5mm) is a 36t.

So now, I'm faced with this dilemma. I can ride a 26/36 x 12-27. Fine for the vast majority of the courses I'll be doing. But I'd really like to be able to use a bigger chainring in front for the courses with rolling fire road sections or transitions.

Shimano states that they use a 50mm chainline. I'm assuming that this is a measurement of a line extended from the the center of BB to the teeth of the middle chainring.

So, does anyone make a chainset with a ~60mm chainline? What about that FSA double?
 

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??

duke of kent said:
So I was messing around with my Paragon last night, taking off the 22-32-44 chainrings and putting on some rings that I've borrowed from the shop for sizing purposes.

To my dismay, I have determined that while a 26t inner ring (great for the 29er) fits perfectly, the biggest ring I can fit in the middle chainring position, with adequate clearance (4 or 5mm) is a 36t.

So now, I'm faced with this dilemma. I can ride a 26/36 x 12-27. Fine for the vast majority of the courses I'll be doing. But I'd really like to be able to use a bigger chainring in front for the courses with rolling fire road sections or transitions.

Shimano states that they use a 50mm chainline. I'm assuming that this is a measurement of a line extended from the the center of BB to the teeth of the middle chainring.

So, does anyone make a chainset with a ~60mm chainline? What about that FSA double?
All you need is a wider BB axle or offset the existing parts slightly to the right. put some of those BB spacers under the right side cup to have the BB moved to the right just as much that a larger ring fits without touching the chainstays. you won't notice if it's just a couple of millimeters. if it would be more maybe try the next wider BB-axle size.
 

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Discussion Starter · #3 ·
nino said:
All you need is a wider BB axle or offset the existing parts slightly to the right. put some of those BB spacers under the right side cup to have the BB moved to the right just as much that a larger ring fits without touching the chainstays. you won't notice if it's just a couple of millimeters. if it would be more maybe try the next wider BB-axle size.
The problem is that I'd prefer to stick with external BB cranksets. I know I can space the crankset out a bit with some wave washers, but I don't know how much I can get away with.
 

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which BB shell?

duke of kent said:
The problem is that I'd prefer to stick with external BB cranksets. I know I can space the crankset out a bit with some wave washers, but I don't know how much I can get away with.
if you have a 68mm shell you can use the spacers to shift the crankset more to the right. however if you have a 73 shell you might have just that 1 spacer (or none if you have a e-type derailleur). anyway . those spacers are the only adjustements you have.

extrenal cranksets once again $uck here. you are stuck with a wide q-factor. "old"-style cranksets with seperate BBs let you choose whatever width and setup you like.
 

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Discussion Starter · #5 ·
Someone posted the attached PDF a while ago. I copied and saved it then, as I thought it might be useful.

When I was re-installing my crankset yesterday, I measured the Q-factor and R/L contributions to the total. To my shock/horror/dismay, the right side, with the 1.5mm spacer I put on, was 9mm further outboard than the left side.

The current crankset is a pair of Shimano M532 Deore cranks; they're by far the worst component on the bike. Are current XTR M970 and XT M770 cranksets offering a similar Q-factor to the M960 and M760 cranksets as listed in the PDF? Similarly, are the left and right offsets the same?
 

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