SRAM shifter compatibility
 

I was wondering if I could use a SRAM rival left front shifter and a Shimano ultegra 9 speed right shifter with a 9 speed drivetrain. Basically it would be all 9 speed ultegra with a SRAM rival front shifter. The SRAM rival front shifter is meant for ten speed but would it matter?

Strange idea, consider that the brake hoods have a different reach and feel. Might work if your right arm is longer than your left.

ok, but in terms of shifting, would a front shifter made for 10 speed be any different than a front shifter made for 9 speed?

Yes, every brand of shifter has a cable pull made to match the lever arm length of their own FD and a FD width that is appropriate for the chain width. Mixing things up is rarely wise, but some mixed combos work OK.

I resemble that remark.