Shimano GRX chainline

joeyhalloran

non-working biking that I am considering spending the money to swap out the SRAM Rival 1x system I have on my cross bike for GRX. The question is; could I keep the SRAM Rival crankset? I know the GRX stuff has a +2.5mm chainline which means front derailleurs need to be compatible, but for a 1x system will I notice any difference?

mr_evil

It's only the chainrings and front mech that moved, so if you don't use those then it won't make any difference.

moonshine

if you are sticking with 1x there should be no noticeable difference.
I found i could not use a road chainset (either my DA7800 SRM or Rotor 3D Power2max chainsets) with the GRX FD - it touched (just brushed) the crank arms in the outer position when on the 11T sprocket
I changed the GRX FD for a Ultegra FD and all is fine - even when using the GRX shifters

tsarouxaz

the chainline is for the crankset, if you will not change the crankset what is this topic about??

step83

tsarouxaz said:

the chainline is for the crankset, if you will not change the crankset what is this topic about??

Pretty much this. your chainline is a result of the offset of the front chainring. The rear mech can only move within the limits of the cassette, regardless if its 9, 10, 1 or 12, it will still have the same amount of space to move as it did before.

Just remember to turn on the clutch on the mech when you set it up (and turn it off if you have to remove the wheel).