Thread: rda discs seem to have warped

Originally Posted by DiscoJeffster

Im sorry to say but there is no such thing as a warped rotor. Runout issues exist and these are normally caused by poor installation. Hub surfaces need to be wire brushed clean to ensure a neat mating between the rotor and hub to ensure runout is at a minimum. Other reasons also exist.
A quick google pointed me to an article to describe it in more detail. Poor run in of discs and/or pad choice might result in build up of pad material unevenly across the disc also resulting in a pulsation. The list goes on. Very rarely is it the fault of the disc

Warped' Rotors Myth - Correctly Service Brakes: Runout, Disc Thickness

And all is back to normal. My mechanic mindful of the warranty requisites of rda checked the following. Caliper pistons.. not cocked moved freely. Pads.. all wearing uniformly and parrallel. Hub clean and free from rust corrosion or any other material that would compromise a flush fit (thats immediately after the rda discs removed). Wheel bearings move as expected
I dont doubt there are many causes of pulsating brake pedals and steering wheel shimmy on breaking but I fail to see how , given everything was meticulously checked prior to fitting and after removing rda discs, it cannot be a warped disc.
I didnt hear back from the gentleman re the delios discs. I wont be putting rdas back on so other than Genuine what have others used
Thanks

Originally Posted by duderduderini

what have others used

I have Brembo rotors and pads. Have been good, though the pads are dusty. Got all the stuff for four wheels delivered for about $500 AUD 18 months ago.

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I still have doubts about yours being "warped" for the reasons posted above. More likely pad matter build up but to
Answer your question. I have DBA rotors all round, Brembo front pads and QFM rears. Love the setup although Brembo pads are very dusty (the price you pay for better performance I guess)

Originally Posted by LRDisco_Fever

I still have doubts about yours being "warped" for the reasons posted above. More likely pad matter build up but to
Answer your question. I have DBA rotors all round, Brembo front pads and oEM rears. Love the setup although Brembo pads are very dusty (the price you pay for better performance I guess)

By pad matter are you referring to matter on the friction side or the backing side?. The calipers were removed in toto (with pads still in situ) and refitted once new disc went on. If the theory, plausible I am sure, of pad matter on the backing plate being a culprit then this would surely dispel this . Given everything was checked and double checked and the problem has now disappeared how could it possibly be anything else?
I might add that this phenomenon (the warpage symptoms) happened well after they were fitted which might dispel theories about the fitting surfaces not being clean et al
I just can't see how it could be anything else.. nor can my a grade mechanic of 35 years experience
No disrespect meant but everything was checked.. and since original discs (which were machined prior to fitment) were placed all has been well. So by deduction pads were not removed from calipers,hence not disturbed in any way, hubs checked and verified clean pistons shown to move freely, pads parallel meaning even wear. Wheel bolts were torqued to spec and bearings fine.
Thanks for the heads up on what components you are using

Friction Material Deposits - Disc Brakes Australia

I would suggest the rotors and pads didn't match well or either the discs or pads were not bedded in correctly leading to the issue, which would explain why others have not had this issue with these rotors

4WD/SUV | Bendix Brakes
The vehicle was bedded in so to speak by my mechanic and secondly they would need less bedding given their design objective
Warping Disc Rotors - Disc Brakes Australia
Discs can warp incidentally
Why Do Brake Rotors Warp? | YourMechanic Advice
So If you need to be right Jeff then you win but I have an alternate totally plausible reality to you
To put it succinctly all the scenarios described in this ping pong debate can cause the same effects. Warping can be a misnomer for uneven wear but I have seen warped discs in kart racing as in if you stand behind them they are wonky.
I just went out and checked my rotors.. they do not have deposits on them anywhere which would be concominant with friction material deposits.
Still if you arent convinced then so be it. I would rather people not buy the rda discs hence my caveat.Incidentally they have offered to replace the discs but I'm not sure I want them again to be honest.
Brembos it is then

So I'd say, did the mechanic use a dial gauge to measure the amount of warping of the discs? If there was warping, a dial gauge would have show it clearly, and the variance. All I'm saying it the term warping is generally a misnomer and thus leads to poor diagnosis of the real issue. The real issue may be with RDA discs, but by the definition of warping, I'd be surprised if it was warped. Any of the other reasons I've posted are more likely the reason, but if changing the discs resolves it then great!