Thread: Slotted rotors - Worth it?

Thats true. I'm more than happy to change pads every 20,000km, for high friction and high temperature pads anytime. Piece of mind and a whole body is good value.

I'm with Slunnie,I have found that slotted disc's weren't the improvement,it was the pads that made the difference. Pat

slotted rotors run cooler so go longer before hitting brake fade and they self clean better so pick up brakes quicker after you hit the mud..

for the fade resistance vented cross drilled rotors work almost as well but without quite so much additional wear.

I fitted dba slotted and new soft pads, (can't remember brand) but well worth it IMO.
They did chew through the pads in under 20k but I recently changed the pads to El'cheapo brand and didn't notice any difference in stopping power.
I'll have to wait and see how long the cheapo's last

Thats the theory behind it, though I don't think that the difference in rotor is significant in comparison to the differences in pads. The other thing the slots are meant to do is reduce the fade effects from outgassing of the pad.

Out of interest, I ran OE plain rotors with EBC 2000 series proper greenstuff pads and drove down through the pass towards Fitzroy Falls in NSW with a loaded tandem axle trailer that had failed brakes. The hotter my brakes got the better they worked and I was able to brake enough to hear the tyres squirm on the road on any/every corner - it was just sensational.

Changed to EBC slotted rotors and EBC 6000 series 4x4 pseudo greenstuff pads and did the same thing with a similar trailer + load but with fully functional brakes and I had to stop on the handbrake part way through the pass - not being able to stop on the foot brake. A very smokey episode.

BTW, I would never ever fit cross drilled rotors to any vehicle. Slotted is fine, dimpled is fine but cross drill concentrates the forces and every hole acts as a stress raiser. These rotors will crack, and even after a short period of time you will probably be able to visually see radiating fractures from the cross drilling. I had a chat to the fellas at Dba a few years ago, and even they said that the cross drilling is basically for the bling brigade on the street. None of their circuit rotors have it. At work, the fellas have managed to fracture cross drilled rotors on a lightweight Pug on a single trackday. The only time we use them is on a lightweight energy breakthrough car that we built, which has minimal braking time while on the circuit, it is lightweight and it is done to get weight out and reduce rotational inertia rather than increase performance.

Originally Posted by Slunnie

Thats the theory behind it, though I don't think that the difference in rotor is significant in comparison to the differences in pads. The other thing the slots are meant to do is reduce the fade effects from outgassing of the pad.

Out of interest, I ran OE plain rotors with EBC 2000 series proper greenstuff pads and drove down through the pass towards Fitzroy Falls in NSW with a loaded tandem axle trailer that had failed brakes. The hotter my brakes got the better they worked and I was able to brake enough to hear the tyres squirm on the road on any/every corner - it was just sensational.

Changed to EBC slotted rotors and EBC 6000 series 4x4 pseudo greenstuff pads and did the same thing with a similar trailer + load but with fully functional brakes and I had to stop on the handbrake part way through the pass - not being able to stop on the foot brake. A very smokey episode.

BTW, I would never ever fit cross drilled rotors to any vehicle. Slotted is fine, dimpled is fine but cross drill concentrates the forces and every hole acts as a stress raiser. These rotors will crack, and even after a short period of time you will probably be able to visually see radiating fractures from the cross drilling. I had a chat to the fellas at Dba a few years ago, and even they said that the cross drilling is basically for the bling brigade on the street. None of their circuit rotors have it. At work, the fellas have managed to fracture cross drilled rotors on a lightweight Pug on a single trackday. The only time we use them is on a lightweight energy breakthrough car that we built, which has minimal braking time while on the circuit, it is lightweight and it is done to get weight out and reduce rotational inertia rather than increase performance.

I'll buy that... Ive had them but then my driving style is normally very easy on brakes... my original pads cleared 60 K Km without problems wear wise (50% useable compund remaing) but due to an oil leak I insisted they be replaced under warrenty as the leak was fixed under warrenty AND I want the originals back as spares.

I fitted the vented rotor conversion from Triumph Rover spares to my '88 Rangie after a severe brake fade episode and I was very impressed with their fade resistance, but I agree with everyone else that they made no difference to the effectiveness of the brakes under normal circumstances.

Logically, just fitting slotted rotors could make no change to brake effectiveness compared to solid rotors given equal rotor temperatures. Effectiveness can only be modified by changing the surface area of the pad or the composition of the pad, either of which will change the coefficient of friction.

At the same time as I fitted the vented rotors, Ian gave me a set of harder composition pads which took a bit of getting used to. They were quite ineffective when cold, but once they heated up to normal working temperature they were much better than the original pads. I just had to remember to work them a bit before I tried any emergency stops - in other words, drive carefully for a few Km when starting out for the day.

I'd thoroughly recommend the upgrade, not for more effective braking under normal circumstances but for peace of mind, especially if towing a trailer or doing a lot of hill work.

I'll be upgrading the front brakes on my Disco soon but as the latest price I got from Ian was $550 for the vented rotor conversion, I'm still working on the cost benefit analysis to submit with the capital expenditure request to the Office of War and Finance.

I fitted slotted and cross drilled DBA gold rotors to my RR (now my Dads) and they are great. Was told the same about chewing out pads but found that to be not true. Pedal and braking were a bit better over standard items but not a drastic improvement.
Hope to do the same to the Fender soon.