Delios discs

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Well, prior to reading this post, I had already bought a set of DBA rotors (non-slotted) and Bendix 4WD pads

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I had Bendix 4WD pads on the DBA slotted discs which I previously had which cracked.

This time around I fitted TRW Lucas pads and found them to be superior as they were softer and appear to make the traction control work better.

Seeing the discs are Lucas brand I thought that the pads would suit . They seem very near to LR branded ones.
Not the cheapest and not the dearest.
Regards Philip A
BTW just reread OP

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So I've had my Delios discs with original pads on for about 7000km and they've developed some pulsation when stopping.

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This is usually caused by a hard spot developing on the disc and subsequently the width of the disc varying.
Well Known in Falcon taxis.LOL
It is usually caused by hard braking say down a hill to a stop eg red light and keeping your foot on the brake and the disc getting very hot under the pad. Its often worthwhile to either stop and run forward a bit or use the handbrake and take your foot off the brake.

Hahaha
This is not a text book promotion hahaha

Don't be salty. But I honestly don't think you know much about brake Rangieman.


I am not a mechanic. I don't even work in the field of automotive. But what I do have is solid basic knowledge of physics. (Yes I am armed with high school physics only)

My educated guess is slotted rotors will produce a worse braking performance and higher pad wear, given the brake pads is clean and doesn't require self cleaning often.

This is simply due to a reduced contact surface for the pad.

Say the friction coefficient of the brake pad remain the same, and of course, the size of the pad the same, then the slotted rotors will have a reduced pad contact surface compared to a plain rotors.

Braking is from friction. So slotted rotors will have a worse braking performance, holding all other variables the same.

As with that "braking gas" thing you talk about, I am gonna laugh at your out-of-date knowledge. Many many many years ago, the bonding in the brake pad is not good and will disintegrate during high temperature, producing gas
But Nowadays, it not a problem.

Secondly the slot/groove will produce a "cutting effect". Mind you this is not the braking friction we desire. And this is also why you may have so-called "brake.dust" in the groove. I think those are graded pad material rather than dust. Yes the slot clean the pads but remember you only need to clean the pad if contaminated.

slotted brake is really a trade off.
Worse braking vs. pad cleaning (plus high pad.wear). If you want better braking go plain. But if you worry pad contamination, go slotted.

If you look at the rally cars, you will see some run plain rotors some run slotted rotors.

Go talk to an expert and get your facts right before promoting your products.

I don't think you know enough to inform what rotor is good.

Have a nice day
Martin

And I like stuffs made I'm China compared to Thailand or Indonesia. I think the Chinese products are just like any products made.
You get what you pay.

But Rangieman, sometimes you can't just ignore the tears of former manufacturing countries. You can't just see the tears on their face and say "oh it's raining"

Martin, a quick lesson on slotting, drilling, etc with disc rotors, and at one point in my life for a couple of years I was paid to spin spanners, draw up test programmes, go to race tracks, and oversee testing things including brakes. ;)

As the pad comes in contact with the disc and huge amounts of heat are generated a lot of gas is also produced.
This outgassing of the resins and pad material burning up can create a cushion of gas between the pad and disc, reducing effective braking.
This excess heart can also lead to glazing of the pad material.

Slots and holes vent the gases away, and both help continually deglaze the pad, increasing effective braking and especially increased initial bite.

This is really only evident under extremely hard braking, and I hate holes, they propagate cracks, been there, done that, nearly had the discs explode on a race car but slots are a really effective compromise.

Does the average driver/car need slotted discs?
Nope.
Do they work?
In my not so humble opinion, yes.
The continual deglaze is a nice thing to have, at the expense of slightly increased pad wear.

Video in this article talks about Gas from Brake pads

Drilled vs. Slotted Rotors - What are the Best Brake Rotors?

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Originally Posted by Roverlord off road spares

Video in this article talks about Gas from Brake pads

Drilled vs. Slotted Rotors - What are the Best Brake Rotors?

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From what I read here is that drilled and slotted rotors cause the pads to wear out quicker and are prone to cracking, The drilled rotors more so.
It doesn't mention it in that article But I would assume that contamination of the holes/slots when negotiating in deep mud and sand will accelerate this wear as well.
This is Not what I want from my braking system on my 4WD as I do a lot of remote driving where replacement rotors and pads are not easily available and I don't drive like a boy racer anyway.
For someone who wants high a performance braking system on their 4WD then the slotted rotors appear to be the best choice as long as longevity and reliability are not an issue.

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Originally Posted by rick130

Martin, a quick lesson on slotting, drilling, etc with disc rotors, and at one point in my life for a couple of years I was paid to spin spanners, draw up test programmes, go to race tracks, and oversee testing things including brakes. ;)

As the pad comes in contact with the disc and huge amounts of heat are generated a lot of gas is also produced.
This outgassing of the resins and pad material burning up can create a cushion of gas between the pad and disc, reducing effective braking.
This excess heart can also lead to glazing of the pad material.

Slots and holes vent the gases away, and both help continually deglaze the pad, increasing effective braking and especially increased initial bite.

This is really only evident under extremely hard braking, and I hate holes, they propagate cracks, been there, done that, nearly had the discs explode on a race car but slots are a really effective compromise.

Does the average driver/car need slotted discs?
Nope.
Do they work?
In my not so humble opinion, yes.
The continual deglaze is a nice thing to have, at the expense of slightly increased pad wear.

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Thanks.

I did the research and it seems that the gassing problem is almost non existent now. Due to the improvement of bonding materials used in the pads

Moderm brake pads will gas at a temperature that the brake fluid will also boil and rotor red hot.

But...I know little about brake pad compounds so I am not sure

The only time mine brake faded in the long downhill at jindabyne going to Tom Groggin

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Originally Posted by martnH

Thanks.

I did the research and it seems that the gassing problem is almost non existent now. Due to the improvement of bonding materials used in the pads

Moderm brake pads will gas at a temperature that the brake fluid will also boil and rotor red hot.

But...I know little about brake pad compounds so I am not sure

The only time mine brake faded in the long downhill at jindabyne going to Tom Groggin

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When negotiating steep descents selecting a lower gear to use engine braking will help to stop the brakes from "Fading" [thumbsupbig]

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Originally Posted by trout1105

From what I read here is that drilled and slotted rotors cause the pads to wear out quicker and are prone to cracking, The drilled rotors more so.
It doesn't mention it in that article But I would assume that contamination of the holes/slots when negotiating in deep mud and sand will accelerate this wear as well.
This is Not what I want from my braking system on my 4WD as I do a lot of remote driving where replacement rotors and pads are not easily available and I don't drive like a boy racer anyway.
For someone who wants high a performance braking system on their 4WD then the slotted rotors appear to be the best choice as long as longevity and reliability are not an issue.

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Holes are an absolute no no in my experience, and apparently cast ones are still prone to crack propogation, and yes, I know Porsche, etc still used cross drilled discs....

I never had a problem with the slotted rotors in the Deefer in fifteen years, the first 3 years running around a farm on black soil (ok, it was nearly 3 years of drought too...)
And lots of dirt/gravel/shale roads for most of its life.

No one needs slots, I've just always run them plus braided hoses because I'm a boy racer that never grew up and they look pretty. :)

Oh, and I like the feel of that combination.

I work on the proviso that running absolutely massive brakes negates any issues with fading etc as i cant drive hard enough to actually get them hot...😅😅 6 spot calipers and 385mm discs are just the ticket...😇