Sram & Shimano crank arm compatable?

Can a sram rival crank arm be used to replace a shimano ultegra crank? Also will dura ace front shifters work properly with the Sram?

You can interchange cranks and chain/cassettes as much as you want between Shimano and SRAM brands. But the other components (derailleurs/shifters) can not be mixed. Well, you can kind of mix the front derailleurs, but the performance is not always optimal.

Is the bottom bracket fitting the same for a Sram and Shimano crank arm?

Is the bottom bracket fitting the same for a Sram and Shimano crank arm?
Generally: No. There might be a couple of combinations where it’s nearly right; but if you want things to work the way Shimano or SRAM intended, you should get the proper bottom bracket to match your crank, and to fit your frame.

Is the bottom bracket fitting the same for a Sram and Shimano crank arm?
Generally: No. There might be a couple of combinations where it’s nearly right; but if you want things to work the way Shimano or SRAM intended, you should get the proper bottom bracket to match your crank, and to fit your frame.

+1. Sram GXP spindle has a smaller diameter on non drive side. Mix compatibility only works for front shifter and FD…Rear will not be.