Hi All,

I bought a pair of DBA slotted rotors for the front and a pair of lucas pads (as recommended).
Now 18 months on, and my brakes started squeeling. Check them at ABS today and the pads
are 95% worn and the rotors (although not warped or anything are 5mm under the legal limit for
thickness. You can clearly sea that its gone down as there's about 1mm lip at the edge. This
really pisses me off as I paid $240 for the pair of rotors and they only laster 18000 kms. Got
protex non slotted rotors fitted with bendix pads (made for the pajero) all up for $375. This will
hopefully last till late 2005 when I plan to get a new car.

Those with DBA slotted rotors, how many ks has it done and is it still ok?

I run Bendix Performax pads on the front and have not had a problem with the DBA slotted discs. I think you meant 0.5mm under legal limit? If it was 5mm under your discs would be worn down to practically nothing, and you would have a much deeper lip. On mine there is hardly a lip after 20KKms + I drive the car very hard; the pads have only smoked once when I was struggling to stay off the bumper of the car in front a few AMC cruises ago. I am thinking of going to EBC greenstuff pads next time as they are a higher temp rating pad.

I am thinking of going to EBC greenstuff pads next time as they are a higher temp rating pad.

They are kelvar pads if I'm not mistaken, so they should extend the life of the discs as they have a low abrasion level, but high friction without being damaging, so I have read :D

They are kelvar pads if I'm not mistaken, so they should extend the life of the discs as they have a low abrasion level, but high friction without being damaging, so I have read :D

Low abrasion but high friction? That does not make sense Haha! I'm not sure of the advantage of using kevlar. I believe kevlar enables a higher temperature rating, without having to use high-temperature organic compounds which are more abrasive.

no problems with Xdrilled and Slotted,

and they get a very good workout!

the pads dont last long :P but the brakes and stopping power is more then id expect from what i got :D

weee!

Low abrasion but high friction? That does not make sense Haha! I'm not sure of the advantage of using kevlar. I believe kevlar enables a higher temperature rating, without having to use high-temperature organic compounds which are more abrasive.

sure it makes sence, low abrasion - low wear on your discs, high friction - high stopping power because if you used dove soap as pads you'd have low friction and you wouldnt be able to stop.

Dictionary.com

Abrasion - The process of wearing down or rubbing away by means of friction.
Friction - A force that resists the relative motion or tendency to such motion of two bodies in contact

sure it makes sence, low abrasion - low wear on your discs, high friction - high stopping power because if you used dove soap as pads you'd have low friction and you wouldnt be able to stop.

Dictionary.com

Abrasion - The process of wearing down or rubbing away by means of friction.
Friction - A force that resists the relative motion or tendency to such motion of two bodies in contact
I think you may have contradicted yourself...consider:

No friction = No Abrasion = no stopping power
High Friction = High Abrasion = high stopping power

Abrasion is dependent on friction.

Another example, rub your skin with dove = good. Rub your skin with a bendix metal king pad = bad (very abrasive/ no skin left) :P

Any questions? ;)

but you can have high friction without high abrasion cant you, like thats the point here, he wants good stopping without chewing the hell out of the rotors. just like tyres yeh?, soft tyres are gonna have great traction/friction but they also take on great abrasion/wear but hard tyres have ok friction and low abrasion.. problem is balance, you want greater braking but changing pads all the time or not so great with not changing pads all the time :cool: .... i dont even know if dove soap is any good, as soap or as brake pads, i might try it out on my car, the paint might enjoy being moisturised with 1/4 moisturiser.

but you can have high friction without high abrasion cant you

Nope, can't have your cake + eat it too.

...Sorry Tek lol


i dont even know if dove soap is any good, as soap or as brake pads, i might try it out on my car, the paint might enjoy being moisturised with 1/4 moisturiser.

LOL...yeah, try that, let us know how it goes hehehe.

Anyway, if you think about it....a car is stopped by a brake pad rubbing on a brake rotor. The more friction between the brake pad and the rotor (assuming pad on rotor contact area is kept equal) the faster the car will stop. The more friction there is, the more heat that will be generated and under most circumstances this will result in greater wear, hence, greater abrasion. If you can find a solution that can dissipate heat fast enough to avoide wear then perhaps thats what were talking about. If Kevlar pads can dissipate heat faster than normal pads and avoid wear by this method I guess they are a good thing. But having said that, the pads being in contact with the rotor, the rotor also needs to be able to stand the heat. Most heat dissipation methods include slotting the rotors, cross drilling rotors, venting the rotors and increasing thickness of rotors or brake pads or changing the materials they are made from.

Under laws of physics (bugger me, this is stretching the memory), the car going forward has so much energy or momentum, in order to slow or stop the vehicle, you need to apply at least as much energy in the opposite direction to stop the vehicle (I know the specifics of this are way wrong). The point of contact is between the brake pad and the brake rotor hence energy is applied through force of pad on rotor, which in turn is converted into heat or wear. Since most heat will break down a pads compound or a rotors compound, the forward momentum is lost as heat between pad and rotor and as such wear. Which is basically the same as abrasion. By increasing a pads area of contact with a rotor (i.e. bigger rotors and pads), heat is dispersed over a greater distance and as such wear is spread over a larger distance and hence abrasion is also spread over a larger distance (greater friction), which equates to less wear per mm squared than what would normally be the case on standard rotor and pad. Of course this is all relative to the speed the vehicle is travelling at in the first instance, the amount of force that is applied by the pad on the rotor (brake pedal pressure), the size of the contact area between pad and rotor and the compound and heat dispersing properties of the pad and rotor.

So to to sum up, and correct myself:

Forward momentum = Stopping Friction = (pad wear + heat) = [abrasion + heat (the more heat a brake pad and rotor combination can stand, the less abrasion].

Another way of expressing Stopping Friction: Stopping Friction = Force of pad on rotor expressed as a function of contact area between pad and such rotor combined with heat dispersing properties of such pad and rotor.

Ok, thats a mouthfull...anyone want to correct me??? I think its basically correct but I'm not 100% sure, any engineers or physics students want to clarify this?

The point with tyres if the theory holds, is that hard compounds would have greater heat dispersing properties than soft, hence, less abrasion. Remember, abrasion is friction that is not converted to heat.

Using such theory applied to dove soap and bendix metal king on skin, hmmmm, **** me ROFL. Ok gotta have a stab at this otherwise I might as well start again....

Rubbing dry dove on skin = high friction. Skin has less heat dispersing capabilities than dove soap, therefore, skin will break down before dove soap, resulting in a **** load of pain and somewhat odd smells (try it, test me LOL). Or, scientificaly, the skins molecular bonds are weaker than that of the dove soap. Applying heat, will force the molecular bonds in the skin to break sooner than that of the dove soap.

Rubbing wet dove on skin = low friction until moisture absorbs heat that is generated and is evaporated. Water has the best heat dispersing properties and acts as a lubracting medium between skin and soap i.e. in this case water has the weakest molecular bonds and is converted to a gaseous medium sooner). After water has been dispersed, the example then reverts to dry dove on skin.

Dry Metal King on Skin = In this example, the metal king tears the skin to pieces. As the metal king pad is of a much harder compound than the skin, its not even necessary for their to be friction in order for the molecular integrity of the skin to be broken i.e. a knife through butter. This basically means that for the molecular bonds of the skin to be broken, heat was not required. Physical force alone enabled this.

Wet Metal King On skin = The water does not provide a sufficient barrier between the pad and skin to form any sort of protective layer, hence, instantaneous destruction of the epidermal layer, per dry metal king on skin.

Ok, thats it [/rant] LOL. If I'm wrong, please let me know as this was quite interesting :D


...I'm off for a beer now.......

You wrong... i uhhh dunno how... but you must be, well how bout this hijacked thread huh? its gone from someone saying their rotors and pads sucked to physicis niiice. are DBA the best money for value rotors to get? what about brake pads? im thinking i may as well put new rotors and pads on while im putting the suspension in, its turning into a weekender job haha, i wanna paint my calipers too, not that you could see it through the rims so i may as well not bother.

You wrong... i uhhh dunno how... but you must be, well how bout this hijacked thread huh? its gone from someone saying their rotors and pads sucked to physicis niiice. are DBA the best money for value rotors to get? what about brake pads? im thinking i may as well put new rotors and pads on while im putting the suspension in, its turning into a weekender job haha, i wanna paint my calipers too, not that you could see it through the rims so i may as well not bother.Yeah, thanks for the hijack guys :cool: . But on a more serious note, I have just emailed to DBA's
national sales manager complaining about the rotors I bought and since they have whats called
a replacement warranty, whether I am elligible. Hope I hear something from them. I am really
disappointed as ABS (Auto Brake Services) along whith other brake services recommended the
Lucas pads. Yes Tek, I meant 0.5mm under the limit which is alot considering how thick they
are to begin with. The original stock rotors lasted 7 years.

So the people with the X drilled and slotted DBA rotors would rate them? How long are they suppose to last? How much did you get your rotors for installed?

So the people with the X drilled and slotted DBA rotors would rate them? How long are they suppose to last? How much did you get your rotors for installed?

Am real happy with the DBA slotted... the slots are quite effective at cleaning themselves if you have a wheel that is a fairly open design with good airflow. You'll find along with any consumable item that there is no expected lifespan.

Am real happy with the DBA slotted... the slots are quite effective at cleaning themselves if you have a wheel that is a fairly open design with good airflow. You'll find along with any consumable item that there is no expected lifespan.
Just like Mars bars eh? put that bugger in the fridge, go back 15 minutes later to consumable it and its GONE.. after the trip up mt glorious last night im hell keen on getting some decent rotors and pads, sometimes i thought i wasnt gonna stop and cut rav in half, plus suspension cause i was floatin and rollin around like a mother****er. So those DBA gold stotted rotors are the AM choice? pads wise whats good to get?

I wouldn't go for full cross drilled rotors for street use as you would be likely to crack them during the constant hot/cold cycles. On the track it's not too bad because you can properly warm them up and down. The EBA slotted & dimpled rotors are a good compromise becuase they aren't drilled right through. Otherwise for a cheaper alternative go DBA slotted. Full cross drilled on the street is really only for looks... it is not only until you push the car to extremes on the track that the advantages of cross drilled outweigh the disadvantages.

yeah i've also heard that u can't machine drilled rotors but slotted are ok.

Drilled discs can be machined too; go to a motorbike workshop if your local mechanic can't do it.

Whats a good combonation people recommend? i just want something thats gonna be better then what i have but i dont wanna be replacing the pads every 6 months or the pads and rotors every 9 months.

The wear pattern Vlad is referring to happens to all cars. They will all develop a lip on the inner and outer circumference of the disc as the pad does not use the full surface of the disc all the way from the hub to the edge of the disc.

ive put in Bendix hi-po pads with stock brakes, the stock pads glazed up in no time bec i live at top of a big hill and there is a long hard stop every time i go down. the bendix pads are an improvement but not enough to turn basically crap brakes into good ones, so i will be upgrading to the EBC setup when these pads go.

no ones named a good combo yet..

the mitsubishi upgrade used on the rallairt magna, awd magnas and Japan/NZ Diamante is meant to be really good. Redav has just done conversion, i drove a car with them once as well and were great. obviously very hard to find locally 2nd hand, but migt be feasible from Japan or NZ.
it seems that DBA or preferably EBC rotors will be good with bendix pads not to "warp" as a cheaper option, a lot of ppl using them only some having problems, as mitsiman said probably due to using metallic eg Ferodo pads.
The other option is the EBC twin pot upgrade, obviously the best bec uincrease the clamping power and the surface friction area as well as the pad and disc material being properly matched and for maximum bite.
basically the more u spend the better u will get, do a search for examples of ppls experience with varios upgrades.

Well, DBA's national sales manager has replied back to my email and I'll contact him tomorrow.
Hopefully something positive will come out of this.