joebeer

hi. i have a 650b randonneur bike with direct mount mafac raid brakes and 50mm mudguards over 42mm tyres. brake post spacing is 75mm. have never been particularly impressed with the performance of the brakes especially when loaded for touring or towing a trailer. in the wet they are just dangerous. i know loads of people love these brakes and say the performance is excellent but i i cant see how it ever can be when the arms themselves have so much flex. as soon as the pads contact the rim most additional force looks to go into upper arm flex (yes i have fitted coolstop pads and played with straddle height and toe in) . i am 14 stone and often ride quite heavily loaded. (4 panniers and /or kids trailer) so they are having to work quite hard but are just not up to the job.
the bushings are now really worn on these and they have developed a lot of slop and play which means they work even less well and are squealing a lot. . i am looking to replace them but dont want to spend too much money unless i know i can get the performance better. (cant afford compass or paul).
does anyone know if the new diacomp gran compe or older 750 can have its backing plate removed fir direct mounting on brake posts? also what is the pivot spacing? both these look to have less flexible arms than the mafac.
other thing i was looking at was old shimano xt mtb u brakes or bmx u brakes. are either of these compatible with standard centrepull studs built for mafac raids? (75mm spacing and 50mm mudguards) could find very little info on standard drop or post spacing for bmx or retro mtb. (i remember an early 90s GT mountainbike i had with u brakes having quite good brake performance)
if i cant find a suitable upgrade for the mafacs then i may opt to get the studs removed and have some canti posts added instead. this would be an expensive faff but i allready have some suitable brakes that i know would work.