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bear351c

Disc rotors - Slotted, Grooved or Drilled. ??

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Was having a convo with a guy at the Clipsal 500 about disc rotors. While we both agreed on vented rotors, there was a difference of opinion on drilled and grooved. My previous set of drilled rotors, (think they were DBA) after a while I found spider cracks radiating from the holes, and got rid of them, for my own piece of mind.

 

So, tell us what you got, who made 'em, are they grooved, drilled, solid or vented. ??

drilled%20rotor.png

 

 

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I usually replace original with slotted and dimpled rotors, either DBA or RDA brands. After reports of drilled rotors cracking like you've mentioned one or both of these companies stopped manufacturing them and only drill little dimples into them(hence the name) thus eliminating the cracking problems while maintaining most of the cooling properties. They've worked great ever since I first started using them on the cars I've owned

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I'm running slotted T2 DBA rotors on both my XF ute and FG G6E. Mostly for the looks really.

 

I think DBA and the "kangaroo paw" ventilation is a step above standard though, and the rotors on the G6E are definitely better than the factory ones.

 

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Cross drilled is definitely out, due to the issues highlighted above.

 

Dimple and slotted is th go but make sure you look at your pad material and fluid as well. The rotors alone are just one piece.

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Yeah, agreed.  We did talk about full synth fluid and such, but, pads were a whole other story..!!  Brand names were being thrown around willy nilly..

Maybe peeps can add their favourite on here, as well. i put some Bendix General (blue stripe) on the ZL, been pretty good so far. Minimum bed in time, and not too much dust on the Snowies.

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Slotted/dimpled are a good way to measure rotor wear too. As they wear, the slot/dimple gets shallower.

 

I like soft pads as they:

• Don't wear the disc as much

• Don't make as much dust (ie: organic, not carbon-metallic)

• Despite slightly lower outright performance, bite a lot more quickly than carbon-metallic ones, which need time to heat up before max friction is achieved.

 

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Bendix HD on my G6E, don't feel hugely different to Bendix CT, but have a shitload more dust.

 

Bendix CT on my ute and wagon, seem all good.

 

Just put some new Repco CT pads on Mum's AU, so far seem so good.

 

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Thing is to not get caught up in the whole brake pad sales talk. You really need to think about your application, how your going to use 'your' car.

 

As an extreme example - no point putting a pad designed for circuit racing on a drag car. Generally circuit racing pads need to come up to temperature to work. The drag car needs a pad that's going to bite straight away and only do one big stop. They simply don't have the time to come up to temp. Sure at the end of the stop they will be worked, but they get plenty of time to cool off and be ready for the next run.

 

Generally a slightly upgraded stock style pad is good for most people, unless you do multi lap circuit racing type events. Of course you need to consider the weight of the car and the whole braking package. It's very easy to get caught up in it all and go for exotic materials used on late model high performance cars, but really you'd need a pretty serious engine and car and application to warrant them.

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I had the DBA golds vented and drilled and they cracked with ferodo ds2500 pads, twice! these were the pads and rotors recommended by Brake Plus for my old EF XR6, they replace the disks and pads free, twice then they cracked again and they gave me a refund and told me to fuck off, went to stock disks and the same pads and never had issues around Nebo and Tambo

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I have RDA slotted and dimpled rotors on the front of the ute with RDA pads and another brand called Toro on the back.

 

Both sets took a long time to bed in and quieten down and i still think after about 1500km they are a bit spongy for my liking. 

 

I was thinking of trying a different set of pads on the front at least.

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As touched on already.

Drilled and slotted rotors are not high performance. They are for looks only. They will work fine on the street. For street duty with street pads. And probably fine for drag racing too. And the once a year trackday if you don't push em.

 

If you are road racing on dirt or tar you need a good rotor. Either flat or slotted. Slotted can cause early pad failure if you run hectic pads and don't bed in properly. Diameter helps with stopping where as thickness and ventilation type are for cooling. Curved vane been the better as it makes a more efficient "pump" to move air.

 

Don't get confused though. "High performance" in this context is not something required on the street unless you're driving like a fuckwit. (seriously, slow down)

 

A decent pad is all most people need.

 

I want to road race, intending on importing a willwood mustang big brake kit. It's a proper functional upgrade, not what the local kits usually are, just a big inappropriate rotor with low temp calipers and pads. This kit is for race. But it's not cheap at around 2500 dollarydoos.

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Spot on Crazy

Simple stuff really , leave a gap ,slow down, give way ,drive to the conditions.

 

Hi Po pads and rotors on the street , really ?

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Running DBA T2 rotors with bendix ultra premium (fancy name for GCT) pads in my ute. The standard rotors warp under sustained braking (like when towing) so I moved to the DBA. No more shudder, pull a load up great and on the off chance I get to go for a fang through the hills, perform brilliantly. Next time? Same again. Happy with how they work.

 

Wife's Corolla, has RDA slotted rotors (were cheaper at time)  and GP Max pads. These are an improvement (slight) over standard, however are shit. The rotors rust virtually overnight, they shudder a bit (not the wheels either) and the pads are dusty. Hopefully won't need to replace these before we replace the car though - its a piece of shit anyway.

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On it josh,

I was running DBA roo paw slotted standard hub replacements in the front, RDA slotted non ventilated rear (E-Series diff) and Bendex ULT's all round.

It went well at a couple of track days, But the last time i was out i was going faster then ever before, for longer. Plus I am armature to tend to lean on the brakes a bit too much(?).

The From my fading memory, result was solid braking for about 4 hard laps. before the pads over temped, I pushed em a bit after that and completely destroyed em. Now they are a crumbling mess. Bendex ULT's are rated max temp of about 500ºc.

The ULT's are a little noisy and a little dusty on the street, but give sufficient initial bite on a cold rotor to be suitable for street use.

 

That sort of effort would be very hard to attain on the street, and you definitely should not try doing it. That is about 5 minutes of constantly pulling a full weight (minus back seat and spare) XF falcon sedan up from up to 160km/h down to cornering speed, at least 6 applications or once every 12 seconds.

That setup would be more then enough for a street application.

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