roughing up discs

gtd.

I have just fitted a set of Hope Mono M4 and Mini brakes, The only 160 and 180 discs I have are an old set of Magura Julie discs.

There very smooth and shiny almost as if there mirror polished so don't work that well

Can I just rub them up with wet and dry?

Neily03

You can but they'll go back to a polished finish again in no time. That's what happens but it doesn't effect performance, just look at the discs on cars.

jairaj

GTD. wrote:

There very smooth and shiny almost as if there mirror polished so don't work that well

This bit leads to me to believe that the OP has already tried to use the brakes but is not happy with the performance?

Disk brakes require a bed in period. Give them time, they should get better. If not maybe the rotors are contaminated. Give them a clean with brake cleaner or alcohol and re-bed. They should come in good eventually

bennett_346

Pad material will build up on the rotor giving you better peformance after a while.

BG2000

Whenever I've renewed my brake pads, I've always rubbed down the rotors with wet and dry, then thoroughly cleaned with IPA. This removes the bedded in deposits from the old pads (which may be a different material). So when I bed in the new pads, it's almost like starting from scratch again. Bedding in takes a bit longer this way, but it's worth it as I never need to do anything until the pads wear out again.

gtd.

all my other discs are fairly flat and rough is these are like chrome polished no roughness at all for the pads to bed into there temp discs till I get proper Hope ones

The are the old Magura Julie discs like these



But mine look like someone has polished them with a mop and compound so they are like a mirror.

Tried IPA and a cloth to no avail even though its the wrong time of year to be bedding pads in

richg1979

rough them up with a some 80-120 grit paper. this also helps bed in the pads.

gtd.

richg1979
Started doing this yesterday, before I saw your reply

Had a pack of Mouse Sander Sheets so used one of the square detail bits , looks better just need to go and clean the discs and bed the pads in

Thanks peeps

gtd.

Brakes have been poor since sanding them, though I'd give the front disc a light rub against the side of the bench grinder. if all else fails I'll get new discs.

Planning on ordering hope floaters next month anyway.

there rougher and working a bit better work better at speed though :? .

Just pulled the pads to shim the front caliper to centralise it

The pads are very shiny (glazed) with a couple of lines (Superstar Kevlar Red pads)

Sanded them so there rough and will try em again in the morning 8)

nicklouse

you need to bed them in now you have been playing with them.

they want to be smooth.

Have fun or just get some new rotors. Clean them and let them bed in.

gtd.

Would the glazing have stopped them bedding in?

They were totally smooth and shiny like glass :?

now there nice and rough

just checked the back pads and they were slightly glazed so roughed them up, I'll set off early in the morning and try not to use them till the big hill at the end of the road then bed them in on the way down

gtd.

There starting to bed in quite nicely

When I pull the brake hard at speed the back wheel lifts slightly

The back has always locked up

I've only done this as a temporary measure till I order another set of pads and then I'll get discs.

I 'll either upgrade to a 200mm front or stay 180 and down grade to a 140 rear as a bigger disc on the back will achieve nothing.

Chunkers1980

Up grade shmup grade. Down/Upgrades are not size related.

gtd.

Chunkers1980 wrote:

Down/Upgrades are not size related.

:?

Larger rotors provide greater braking force for a given pad pressure, by virtue of a longer moment arm for the calliper to act on.

Chunkers1980

That would be 'size'. Grade refers to quality.