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(Grinding and wobbling under heavy/prolonged braking) When the pads came off they had loads of life left in them. I have now come to the conclusion that my discs are probably warped. 
..black diamond grooved discs excellent. Got them on the front of mine and hadn't had any of the previous braking issues that i did have (though that said, I put stainless hoses on, DOT 5 fluid and pagid pads at the same time too). Don't really like the pads much as they take too long to warm up and don't give much feel, but the discs are excellent and stop them glazing. Wears pads fast though..... they came on my 2 and felt pretty normal, and warped after a couple of quick stops! Then I swapped for cheapo discs and EBC red stuff pads - looads better. I've also heard horror stories about drilled discs fracturing.Tom G wrote:
Works for me! 
(EDIT: To be fair these had done a lot of trackdays)
They are not just machine blanks, these have proper curved internal cooling vanes and radiused holes. They did approx 2k road miles and half a rockingham trackday with Ferodo DS2500 pads. Don't get cross drilled ones-nothing but trouble.. The grooved only ones are the ones I have and are very good though - and all you need on a road car! The grooves are the bit that deglaze the pad and thats really all you're interested in 
I have just retired after 50 years as a mechanical engineer, with the last 7 years as design engineer at a disc brake manufacturer. I have also been involved in various forms of motorsport for the same length of time. In 1972 I had the first production gearbox kart with disc brakes from Zip Kart. Great until it rained, then stopping became next to impossible at the first corner. I needed to be in mid grid just to get bounced around the corner! Abvout the same time I saw a photo of a Kawasaki bike being used at Daytona with drilled discs. They must have had the same problem. So I drilled the discs in a similar pattern and lo, problem solved and I could stop for the first corner. The reason was the holes allowed the water that could not be sqeezed off the disc by the pad, to have somewhere to go. This drilling pattern became the norm from then on. Later as a design engineer on disc brakes I had, of course, to study many affects of discs, pads and calipers and realised many possible problems. Do not use drilled discs unless it is a special case such as front discs on karts. Use grooves to clear any possible glazing due to the wrong pad/disc/temperature combination. Use discs with a hardness of a minimum of 200HB ie SG iron or steel with a minimum grade of 43. Cast iron is no good.Tom G wrote:I wouldn't recommend them.
So my advice is get some good pads.
- they also warped after spirited road use very quickly (<month) 
(n/a's and sc) with uprated pads (yellowstuff) for all road and heavy track use. 'somethings' on it (can't remember make) 
also ensure the calipers are serviced to make sure they are not uneven braking, which can itself lead to disc warpage
(and hand brake cable) what would people recommend please?Grendel wrote:Sorry for another tread hijack but think my pads need changing soon
The car is only used as a road car is it worth just going to KwikFit and geting them to replace them with standard pads again?
(or local autofactors) and EBC Redstuff - wouldn't waste time or money on greens or blacks | 99 528i SE Touring | 01 Mandarin VX220mr2mk1chick wrote:
edit: our track car has grooved
(not drilled)... well they were grooved, but the race spec pads have worn the grooves away, but only after about 4000 track miles | 99 528i SE Touring | 01 Mandarin VX220Grendel wrote:Sorry for another tread hijack but think my pads need changing soon
The car is only used as a road car is it worth just going to KwikFit and geting them to replace them with standard pads again?
& rear of my car with black diamond grooved discs all round too, im not overly impressed with the black diamond grooved up front to be honest, they were only replaced last year & within 6 weeks the front were slightly warped, im now considdering getting a different set of grooved discs up front or getting these ones skimmed, anyone any ideas how much skimming should cost ? if its not cost effective i may just go for new grooved discs up front instead 
, cheers, jinxy Its a good place to go if your from around the Bath area. He recommended buying standard discs of a decent manufacturer and keeping the ferrodo race pads that I have.... the steering wheel. Seems they have sheared off the spline bit from the top of the column in an effort to break the steering lock! Seems odd though because they left the stereo, which had the head unit and the remote left on it! Now I have to figure out what to do as its stuck on the drive. Anyone have any ideas? I think maybe I'll post in a separate forum