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I want the bite back on my discs....


Tim-Rodriguez

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Hi everyone...it's been a while.

So...

I have a back and front hope mono trial disc on my mod and when I got them new the braking power was amazing.

With time they have lost that bite and I have tried disc brake cleaner as well as the water and heat trick, I also bought new brake pads but had no luck getting them to be like when they were new.

I spoke to another rider and he said I would have to buy new rotors and pads at the same time...is this correct?

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Try scuffing up the pads and rotor surface with some emery cloth / wet and dry and then bedding them back in. Then bed them in together, there needs to be pad material transferred onto the disk surface before they will start biting again.

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It's correct if you want to buy new rotors and pads, yes. But give them both a bleed, or if they dont need it, pull the levers in fully (but gently) and let them slip out of your fingers so they spring away from you. do that continuously for 30 seconds or a minute and then try using the brakes normally :)

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another vote for jitsie pads, but you might as well go whole hog and get your brakes serviced and get new rotors whilst your at it; nothing worse than banging on new pads and ruining them with contamination the same day :(

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I did try scuffing the pads as well as disc with sand paper and it made no difference, but I will give it another go again.

The brakes themselves feel fine as in they don't feel spongy and everything returns as it should, so no need to bleed or push bits about.

If all else fails then I will look into these jitse pads and new rotors as these non grabby brakes are as good as v-brakes from the 90s

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You need to really scuff up the surface of the rotor and pads, use a sheet of wet and dry paper laid on a flat surface (sheet of flat glass, worktop or chopping board will do) and use alternating circular and figure of eight motions.

The danger is with the pads is that it's very easy to sand them at an angle which will ruin the power of them massively, especially if they're formed into opposing wedges. Disk brakes work best when both pads hit the rotor completely flat and at the same time, if one pad is hitting the rotor first then you either need to reset the pistons or recentralise the caliper.

If you can, use a vernier caliper or micrometer to check the thickness of the pad on all four corners and the centre point, if they're different at all then it's going to be easier to buy new pads, if the measurements are the same then look at the caliper.

If one piston is moving more than the other it's likely to be a sticky piston seal, take the pads out and pump the lever to push the pistons out a few mm, use an unfolded paperclip to apply a single drop of oil to the top to the piston where it enters the caliper body. Push the pistons back in with a plastic tyre lever or similar and capillary action will draw it into the seals, cycle them out and in again a couple of times, mop up any stray oil and refit the pads.

If both pistons are moving equally but hitting the rotor at different times (flexing in the rotor when they hit is sympton of this) then recentring the pistons should cure this, also check that that the rotor is running centrally in the caliper slot.

I use 18 year old hope minis on my mountainbike and whilst they don't have the outright power of modern brakes they work perfectly, I never bleed them and only carry out the maintenance above once a year or so :)

Edited by forteh
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