Dixcel SD rotors with Dixcel M pads - noise (squeal & clunk)

by **cynner** » Wed Aug 13, 2014 2:31 pm

I have Brembo's with Dixcel SD rotors and Dixcel type-M pads.

I find that these squeal really loud when cold... it takes a few hard stops for them to quieten down. My mechanic suspects the pads are quite hard and are glazing over with daily driving.

I also find if I brake in reverse, the pads clunk in the calipers (I guess slight movement). Then again when I go forwards and brake the first time after being in reverse, the pads clunk again as they shift. They have been checked by my mechanic and all looks OK - he said the forwards/reverse clunking is not too uncommon.

Do other people with Dixcel rotors/pads notice similar noises?

by **jaydece** » Wed Aug 13, 2014 3:40 pm

I never experienced any of the faults you describe above? I have recently changed my front pads to ferodo and when cold they will squeal, more when reversing....but once warmed up they are fine...I still run dixcel rear pads and front / rear dixcel rotors with no issues up until now.

by **owen** » Wed Aug 13, 2014 4:48 pm

If your pads are clunking and your mechanic says that's ok, the first thing you need to do is find a new mechanic.

by **Manaz** » Wed Aug 13, 2014 5:41 pm

I loved my Dixcel rotors/pads. I've still got the rotors, but with the R33 brakes came Hawk Ceramic pads, and they're just nowhere near as good as the Type-Ms - the hawks are noisy and horrid when cold, whereas the Type-Ms were quiet and great from cold...

by **SegR** » Wed Aug 13, 2014 6:56 pm

After what might be a couple of years on the car, my rear type m pads (in 3.0/gt calipers on sd rotors) squeal a bit when cold in reverse. The clunking doesn't sound normal. Maybe they're not a firm fit without shims? Check you have the right pads for your calipers too though I would hope the mechanic would spot that.

by **satogixxer** » Wed Aug 13, 2014 7:09 pm

owen wrote:If your pads are clunking and your mechanic says that's ok, the first thing you need to do is find a new mechanic.

Really?

Michael @ Garage 88 told me this was normal, and explained why.

I have Dixcel Z's on the front and ES pads on the rear with Brembo calipers. I get occaisional clunking just like Cynner described.

The explanation I was given as I understand it, was that the pads were slightly smaller than the maximum size that could fit in the caliper, so they will move a bit sometimes especially when cold or even with most normal driving (i.e. when first braking in reverse or forward direction).

The reason for this was to allow expansion of the pads if they get very hot. Certainly after a track day a few weeks ago, when reversing into the pit garage after each session I didn't experience any clunking. Yet when I reverse into my parking spot at work they clunk most of the time. So the explanation seemed reasonable to me and fit with my real world experience.

Generally I would trust what Michael says, but I would love to know if someone thinks the explanation I was given is wrong or can explain why this should NOT happen, as I get the clunking noise frequently!

by **dr20t** » Wed Aug 13, 2014 7:10 pm

My dixcels clunk when cold too

by **owen** » Wed Aug 13, 2014 8:04 pm

Sorry, my assumption was that you meant that were rattling because they were loose, I didn't realise that they were designed to expand which is a perfectly good explanation. Pls disregard what I said earlier.

by **cynner** » Thu Aug 14, 2014 7:52 am

Cool thanks guys. Do those with Dixcel rotors/pads have the slots pointing upwards to the front of the car, or downwards to the front of the car? Upwards (or reverse fitment) is reccommended by Dixcel but wears pads out quicker...

by **satogixxer** » Thu Aug 14, 2014 9:14 am

My FS rotors are fitted in the "reverse rotation" (upwards) direction, i.e. the direction that is recommended for 6 slots - it will wear more but brake better.

by **cynner** » Thu Aug 14, 2014 9:22 am

I wonder if fitting non-Dixcel pads (that might not be as noise when cold) would get eaten up by the slotted Dixcel rotors fitted in the reverse direction? I'm debating whether to put in quieter pads, and if I do maybe turning the rotors to the forwards direction (pointing downwards towards the front of the car)...

by **satogixxer** » Thu Aug 14, 2014 10:01 am

I wouldn't think fitting different brand pads would be a problem. No idea what to recommend for you however.

I'm very happy with my Dixcel Z (front) and ES (rear) pads. I don't have much if any noise/squeal, the braking is tremendous and great on the race track. Only drawback is the huge amount of brake dust but I've learnt to live with it and clean my wheels regularly (so these might not be for everyone).

by **senator** » Thu Aug 14, 2014 11:13 am

The clunk occurs due to the pad backing plate being slightly under sized, so that when the pads are used to full efficiency (get hot) they can expand without damaging the calliper carriage.

The squeal issue comes down how the pad is used/abused……. Type M’s are the quietest pads I’ve used.

I also ran the FS heat treated rotor with TYPE Z pads as daily combo and even those were squeal free.

There is a lot of debate regarding bedding in…. for Dixcel combo I found Michaels advice worked, drive NORMAL and don’t ride of hit the brake pedal too hard for a few days after install.