Am fixing my friends sons bike – it has an old style hope mini on the back. I took it for a quick ride last night, the brake has very little power, and the lever ‘pulses’ when engaged – i bled the system and the pads are new. Both pistons seem to be moving ok – anyone out there got other ideas?

Oil on the disc from the chain? Bent disc?

I still use original minis (probably from the first batch made) and they’re still fine. They’re so simple that as long as the pistons aren’t stuck, and there are no fluid leaks, there’s nothing really to go wrong.

It does sound like the rotor.

If the pads are new, give them a good soaking for 20 seconds with a hose and then nip up & down the road for 50yds with the brakes on. If I do that a couple of times it always sorts them.

Cheers

I can spin the wheel with no obvious rubbing – but can see the rotor is cleary warped – this would account for the pulsing feel i guess time for a new rotor i think – over to the classified section…

Try straightening the disc using an adjustable spanner – you have nothing to lose

Rotors can be bent back succesfully. Gentle application of a Birmingham Screwdriver is recommended.

Yeah I had an original mini on the back of mine which vibrated hard. I think it was to do with the holes in the disc and dirt build up. Cleaning it stopped this but didn’t last long. Solved by replacing with an old hayes round disc. Much better.

Depends what you mean by “pulsing” – mine makes a nice pitter-patter noise when used hard but has never pulsed, even when the wrong rotor size was used and only half the pads were engaging (rotor too small). Too large a rotor may cause it to brake mostly on the rotor spokes, causing pulsing?

by pulsing i dont mean a noise, you can feel movement coming back through the lever, brake power is low, less then say a v brake – you can hardly lock the wheel up. Am going to try strightening the disc but it doesnt look too bad – might just get him a new rotor