If it is a stock crank then this will be what you want to buy.I know because I have two sets of these.Don,t let the name on it mess you up.It is the same that come,s on a stock Surly LHT if you have a 170mm crank arm.This is what you need to get.I know it says cross crank but it is the same model and the # on the back of the crank will match up. Hope this helps out.
Dimension
170mm Cross Crank Arm Set 110/74 Black, Includes Bolts (CR2330)
$38.95