im looking to change the master cylinder on a 1098 sf what width do i choose? 17mm 19mm 21mm etc? cheers
For me, a 21 would be too wooden, the 19 has the right balance of feel and stopping with 1 or 2 fingers which is just right for me. I think the 17 would require too much effort to give you enough braking. Andy
Smaller is less effort but more travel. The amount of fluid you need to shift doesn't change so it's easier to push a smaller piston but it has to travel further.
What calipers do you have ? I have a Brembo MCS 18 multi adjustable in the for sale forum , ideally suited to the M50 calipers
@Pablo Pirate will do you a good deal on a Hel adjustable M/C which will be much cheaper than a new Brembo.
Possibly a better initial question should have been, which size master cylinder would be best for brembo M4s