About a month ago I changed the front brakes on the motor (Calipers, Pads and discs) due to a sticky caliper.

Everything was fine for a few weeks but now i get a vibration under breaking (it's worst between 40-30 Mph).

Has anyone got any ideas?

Cheers

Have the wheel nuts been torqued properly and in the right order?

Yep, I've checked that.

Did you bed your brakes in properly?

Did you thouroughly clean the disc to hub mating surface,were they OEM discs or after market,there are some rubbish AM discs about that like to warp.

Hi sounds like you have a warped disc ; try to get hold of a dial gauge and check the run out on each disc ,if its more than 2 thou remove the disc clean the faces of the disc and hub . reassemble and try again ;you can try the disc in different positions on the studs sometimes this will give a better result in 1 place than another . If the problem still persists I'm afraid new discs will be required ; clean all faces and set up with a dial gauge as described . Tip after heavy braking do not stop and leave your foot on the brake pedal ,heat transfer from the pads can warp some discs in that local area.

it seems to be a common enough problem on is 200s. ihave fitted new calipers new discs and new pads due to the same problem and no change and a mate of mine has the same problem with an altessa. im at a loss too

me 2 chaps, had new discs and pads in ,cause i had warped discs and the warpness has gone but there is still a slight clicking noise from the passenger front calliper, really is just a pain in the side lol, was thinking bout new calipers but now i dont know if there is anypoint if its not going to help lol, good luck with yours lad