Thread: Slotted Disc Rotors?

One of the biggest advantages of the DBA slotted rotor on a 4wd is after exiting water / mud crossings...

Pad feel comes back far quicker than a smooth rotor.


Running the 35's on my D1, and the 33's on the D110 the slotted rotors consistantly gave a better bite to the brakes and shorter stopping distances - particularly when doing the Stab, Accelerate, Stab type tests.


And for the record... I faded brakes on my Landies more times than I care to remember prior to fitting slotted brakes.

Although, the worst performing brake package I ran was EBC Green Pads on their Slotted Dimpled rotors.. They are, in one word... ****e

Originally Posted by Shaker

I got a bit of a shock the other day when I looked at the front discs & saw the size of the lip around the perimeter.

In the past, with other vehicles, I have used RDA slotted rotors as replacements, are there any issues with using these or similar on the D2 TD5?

Any other recommendations?

I couldnt get DBA at the time so went RDA slotted and partially drilled - Bendix 4x4 pads- a tiny squeal when cold, gone at end of driveway and very little dust- no issues - > 30K so far and hardly any wear - needs a bit more push on the pedal but that would be the pads.
Steve

Originally Posted by discowhite

cross drilled are the issue not slotted.
the slots in the disc face are only 3mm max deep, no mud in there
the cross drilled slotted and vented(all on the same disc) ones tend to lead to cracking, dont think ive ever heard of any fail though.

cheers phil

Originally Posted by Tombie2

Spot on Phil...

Slotted are fantastic offroad, clearing grit and muck from the pads and preventing damage from trapped materials.

Ditto

Originally Posted by Tombie2

[snip]

Although, the worst performing brake package I ran was EBC Green Pads on their Slotted Dimpled rotors.. They are, in one word... ****e

Funny you should mention this...

Quite a few years back I was talking to one of the design/test engineers at DBA and asked about EBC pads. At the time DBA were doing a lot of track testing.

He hated them, far too inconsistent batch to batch.

Originally Posted by catch-22

slotted for your application simply means less surface area which technically means, less braking power. Slotted does play a big part in certain applications, however. I love the APracing slotted pattern.

Cross drilled is not that bad at all. New Porsche GT2 RS still uses them, for example So do Lambo and Ferrari.

There is a huge difference between drilled and cast cross drilled discs, and IMO drilled type cross drilled discs are asking for trouble, particularly on a 4WD.

Given the choice, and having run slotted and drilled and slotted discs on race cars and slotted discs on a Defender, I'll take slotted every time thankyou, unless the holes are cast in.

Drilling creates a stress raiser which propagate cracks leading to catastrophic failure.
We destroyed some AP Racing discs in one practice session thanks to being cross drilled. (the AP discs also had some major core shift that DBA didn't, but that's another story)

Getting hot enough to create the cracks may be unlikely on a road going vehicle (they don't see the brake temps of something running on the track) but can happen with red hot discs and, say, hitting a causeway.

Originally Posted by Tombie2

Although, the worst performing brake package I ran was EBC Green Pads on their Slotted Dimpled rotors.. They are, in one word... ****e

I think that is due to the EBC 6000 series 4x4 pads. Absolute disaster of a pad and you can smoke them (literally) without too much effort. Why they would replace the 2000 series pad with these I will never know.

Originally Posted by rick130

Funny you should mention this...

Quite a few years back I was talking to one of the design/test engineers at DBA and asked about EBC pads. At the time DBA were doing a lot of track testing.

He hated them, far too inconsistent batch to batch.

I had lunch with them and in our discussions even they reckon the X-drilled range were for aesthetics. I didn't think they did race rotors with X-drilling. Well, that was a few years ago now.

Originally Posted by rick130

We destroyed some AP Racing discs in one practice session thanks to being cross drilled. (the AP discs also had some major core shift that DBA didn't, but that's another story)

Getting hot enough to create the cracks may be unlikely on a road going vehicle (they don't see the brake temps of something running on the track) but can happen with red hot discs and, say, hitting a causeway.

You don't even need to get the rotors to red hot to crack them. I personally haven't run X-drilled rotors but a former workmate pulled these out of a Pug 205 (Mi16 motor) and they had fractured from every X-drill after 1 track day.