Originally Posted by
LesterOfPuppets
I'd estimate the diameter of the cable run in the (Sram Gripshift 600 and MRX) shifter to be about 1 5/8", you'd have to have some Mega grips to beat that. Maybe some pipe insulation would get you there
I haven't taken one of those apart in years. However, that being the case you might be looking at a M.A. of close to 1.0 (or maybe even less) which only makes a stronger case for the inadequacy of using twist grips for braking.