Thread: are ventilated discs batter than solid?

and hands up those of us that do/have raced that have seen drilled discs crack and/or otherwise fail and luckily lived to tell the tale.......

Vented
Slotting
Drilled

as has been said, venting is very usefull to reduce fade.
If you don't hammer your brakes (I do) they may be a waste of money, although I view it as a safety issue, so would fit them, regardless if you thought they are overkill or not as you never know when you may have to tow something heavy down a mountain side.

Slotting increases initial pad bite by venting the gasses that build up between the pad and disc face and helps to keep the pads de-glazed and reduces or eliminates taper wear of the pad.
Drilling can be more effective in these endevours than slotting, at the expense of disc and pad life. Unfortunately the holes create extremely effective stress raisers that propogate thermal cracks at an alarming rate.
Yes, Porsche uses them on some models (I believe these are cast, not drilled) and some (not many) race cars use them, but they are 'lifed', ie. chucked before they start to crack too badly.

I used to keep a massively cracked race disc hanging above my desk as a reminder of my stupidity ........

Smoking discs? OK, the racing failures make sense - there the whole game is the split seconds gained by latest, heaviest braking. But smoking down a public road?

I live in Toowoomba - on the side of the Great Divide - and I've been in vehicles with smoking discs down the Range (as we affectionately call it) and I've put it down to driver error every time. I've never so much as got the drums on the Stage 1 warm down the Range - if i've any sort of load on board I use them less than if it's just me. That's cause I was taught to rely on engine braking down hills. I use second gear if loaded, third if light and if I was to tow something down (which I haven't yet) I'd probably go for first. It's not a race and the seconds "saved" with using a higher gear are the problem, not the design of the brakes. Keep em cool for emergencies.

It's not just the Series I do this in - I do the same with the Hyundai Getz which has 4 wheel discs and ABS plus weighs nearly nothing. I just have a greater safety margin in the Getz.

Isn't going slowly down hills one of the whole reasons for 4wd and low range transfer cases?

Steve

Each to their own I guess. Modern brakes on cars and 4WD's should be good enough. If they smoke up then there is probably a problem with them.

I've had EBC pads and factory rotors and the hotter they got, the better they stopped. EBC pads and EBC rotors I've never got to work together, with fade problems. Fitzroy falls pass in the Southern Highlands (NSW), I pulled down the Disco with a tandam trailer. EBC pads and factory rotors would stop on a dim every time, and at the bottom I probably could have locked them all up if it wasn't for ABS.

EBC pads + EBC slotted/dimpled rotors completely faded, I had to stop and let the smoke clear. Same hill, same trailer, except during the EBC/EBC run, the trailers brakes were working.

Also, I would never ever use drilled rotors. They just plain crack with multiple fractures radiating out from every hole (I've seen this on day old rotors!) and are not ever worth contemplating. Not even for that "cool" look. They should be illegal. The Dba xdrilled rotors are not race rotors, they're all about bling. Their competition series rotors are a different design (well they were when I talked to them about 1.5 years ago).

From Dba's website:

IMPORTANT NOTICE: Cross-drilled rotors are recommended for street use only and not for racing or track applications.

Originally Posted by Slunnie

Each to their own I guess. Modern brakes on cars and 4WD's should be good enough. If they smoke up then there is probably a problem with them.

Good enough for unlimited brake force over unlimited distances?

Engine braking IS capable of unlimited distance and with a low range gearbox, very considerable brake force. But it's not either/or - brakes compliment the engine braking and vise versa. All brakes eventually fade. That's why our ancestors decreed engine braking for descents. Better brakes means it takes longer before the fade happens, but the principle is the same.

I'll take a blue pill and lie down now.

Steve

No, it hasn't kicked in yet!

If you use engine breaking, and something gives out then you can use your (cool) brakes to make an emergency stop. If your brakes give out you won't be able to get the gearbox into a lower gear to rely on engine braking as an emergency stopping method.

Why do you think Semi's make so much noise going down hills? They're backing up their exhaust gasses to increase compression and engine braking. They're not relying on "modern brakes" capacities.

Maybe it was the wrong pill. I'll try a different one this time.

Steve

Originally Posted by Slunnie

Each to their own I guess. Modern brakes on cars and 4WD's should be good enough. If they smoke up then there is probably a problem with them.

I've had EBC pads and factory rotors and the hotter they got, the better they stopped. EBC pads and EBC rotors I've never got to work together, with fade problems. Fitzroy falls pass in the Southern Highlands (NSW), I pulled down the Disco with a tandam trailer. EBC pads and factory rotors would stop on a dim every time, and at the bottom I probably could have locked them all up if it wasn't for ABS.

EBC pads + EBC slotted/dimpled rotors completely faded, I had to stop and let the smoke clear. Same hill, same trailer, except during the EBC/EBC run, the trailers brakes were working.

Also, I would never ever use drilled rotors. They just plain crack with multiple fractures radiating out from every hole (I've seen this on day old rotors!) and are not ever worth contemplating. Not even for that "cool" look. They should be illegal. The Dba xdrilled rotors are not race rotors, they're all about bling. Their competition series rotors are a different design (well they were when I talked to them about 1.5 years ago).

interesting comments about EBC pads with EBC rotors. this is one of the options i have been looking at.
you'd suggest that the factory discs are better?
which EBC pads do you recommend?

thanks.

I run a 2005 Kia pregio as a courier van, I have approx 130,000kms on the clock with the original brake pads on it I personally inspected the pads myself last service, I can attest to engine braking. Using the gearbox to slow down will reduce the wear and tear on the brakes dramitically