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Discussion Starter · #1 ·
Bike: 2012 El Mar ss
Current crank: Fire Pro XC
New crank: OEM 2x10 Shimano XT + XT BB

I have a bb tool, chain tool, chainring nut wrench, chain whip, grease, etc. I think I have all I need, just never done this before and would love to learn instead of taking it to lbs (nothing against them, just want to learn).

Cranks appear to be the same bcd so chain ring should just transfer over?

How do I know if my chainline is right? What spacers should I use and on which side?

Help a noob out!
 

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Chainline:
http://forums.mtbr.com/singlespeed/chainline-math-738755.html

There is also a thread here on centering your chainring. I dont use it because Im not that picky, but you may find it is helpful... you gotta search for that one tho

Torque wrench if it suits you... It takes some muscle to hit the spec on most cranks so make sure you set the bike up in a way that its not gonna fall over. Also make sure you dont under-tighten it. I had a lbs build a bike for me and the cranks loosened up every time I rode despite me tightening them... The threads eventually (a few months later) became warped and i had to replace the crank.
 

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It's actually pretty simple.
The cranks will come with instructions for spacers. You will need to know the width of your bottom bracket shell.
You really should try to get the loan of a torque wrench.
Don't be surprised by how much drag there is right after the install - it will loosen up.
When you put the non-drive side arm on, I tighten the threaded plastic center retainer as tight as I can get it with my fingers, maybe rap on the drive side arm a few times with a rubber mallet to make sure it is seated, then I loosen the retainer and just tighten it firmly with my fingers.
When you tighten the non-drive side arm pinch bolts, you need to tighten each bolt alternately, a bit at a time.

Check them again after you have ridden a few times.
 

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You don't need a chain whip. You also don't need to worry about the chainline if your current crank is working okay - just make sure to put the single ring in the same position on the Shimano crank as it was on the original crank. A torque wrench is nice, but not really necessary. Just don't get too carried away tightening the pinch bolts on the crankarm when installing the Shimano crank. Use the little rotating part of your BB tool to hand tighten the left crankarm onto the BB (Park BBT-9 tool), just tight enough that the crank spins freely but doesn't have any side to side play. You have a 73mm BB so you only need one spacer and it goes on the left/non-drive side of the bike. Remember, one side of the BB is threaded opposite and so is one of the pedals. Use grease on all the threads. The Park tool website has some useful videos that might help. And finally, if the chainring bolts spin when loosening or tightening, there is a cheap little tool made just to fit in the slot of the backside of the nut.
 

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Discussion Starter · #5 ·
I do have a torque wrench, but how do I use it with the park bb tool?

Can I reuse the old cranks chainring bolts?

Thanks for the responses.
 

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I assume you don't have the park tool designed for a socket wrench.
Hopefully you can use the torque wrench on the pinch bolts, although you need an inch pound wrench or other low torque wrench.
Yes, you should be able to reuse the crank bolts.
 
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