SRAM S300 Courier cranks & chainline
 

Hello,
Trying to get the chainline correct with my Surly Crosscheck & SRAM S300 courier cranks. I'm using The stock Surly wheels that come with a Steamroller "complete". This bike also uses a 68mm x 103mm BB and a 120mm spaced rear hub. I think the S300 has a 42mm chainline (based on some searches, but not confirmed). The Crosscheck has a 135mm spaced rear. Not sure what the chainline should be and am really confused/concerned.

How do I get it right?

Thank you!

Bad question? Did I miss an important detail somewhere? Is there no one right answer? Suck it up and figure it out for myself with a ruler?

Surly 120mm hubs are designed for a 42mm chainline (see if it looks like the one shown here: http://sheldonbrown.com/harris/fixed-hubs.html). According to the Harris Cyclery page, the hub has enough axle to be spaced to 130mm. The crosscheck has 132.5mm spacing to allow it to use 135mm and 130mm hubs (http://surlybikes.com/crosscheck.html). All you have to do is add some spacers (add the same amount on each side for an overall width of 130).

hub info:
http://surlybikes.com/files/NewHubs_07.pdf

Not sure that this is much help at all, but I ended up using some chainring bolt spacers to push the chainring closer to the bike to get my chainline right. (Formula hub - 42mm chainline, if I remember correctly). --- This is the S300 Courier with GXP BB I'm talking about. I read somewhere that it apparently gives ~41 mm chainline, but mine didn't turn out as such (obviously), but that could because my frame alignment might off in the rear triangle.

Hmm, lost my post. Leed you're right, the chainline is off by about 1mm. I think the SRAM is off as it seems the chainring is slightly (1-2mm) further outside. That should be within reason though.

jmartinez you're also right in that the spacing of the rear wheel/hub pulls the rear triangle in a bit. Not sure if this is a bad thing, but I've run this frame as a fixie for a couple years without issue.

Here's a horrible phone photo of it so far...
http://lh5.ggpht.com/_sxOQ5ebzXiM/Sq...ture%20069.jpg

Looking at that pic I really need to paint the walls in my basement...