Switched to compact crankset, now chain rubs on 50 when in the 34...?

[velostring]

I just put a 50/34 compact crankset on my road bike and now find that when I am in the 34 in front and 12, 13 or 15 in back, the bottom chain length (coming off the rear derraileur) rubs on the 50 chainring...how do I solve this? Is there a spacer I can put on the front between the chainring and the bottom brcket to push everything out bit from the frame so it doesn't rub? Has enyone else had this problem?

EDIT: OK - as I read more on FSA"s site I see this is just a compact issue and not much can be done....bummer.

Thanks, Nick

 

[gclark8]

Yes it can be fixed, its a chainline issue. Several of my customers now have a 2mm spacer between the BB tube and the drive side bearing. Yes FSA, not Shimano.

 

[Scotty_Dog]

Go here http://www.sheldonbrown.com/gear-theory.html and be sure to read the section titled: Chainline and Criss-Cross Gears.