I’m potentially in the market for a used SRM (D/A 10 speed.) Is there anything about the design that prevents the use of different sized chain rings? I typically ride a 54 up front and sometimes a 56 for short, flat courses.
There are no problems swapping chainrings on a SRM. With the FSA version you need to remove the inner chainring first to get at the bolts for the outer ring though.
You can swap chainrings, in the SRM I’m selling over on the Classifieds Forum (shameless plug), I’m offering it with a FSA K-Force Aero TT Chainring.

No problem with the shameless plug, but I just switched my BB to the newer 10-speed version and don’t want to go back to Octalink.