I THINK I have a NEW brake pad question

DEpointfive0

I think this will help the people who ask what are the best pads for street and track, and we all invariably say, 2 sets of pads are best.


Here it goes:
What are THE MOST aggressive pads that won't squeal? (After that is answered) which ones have the least brake dust? (Definitely not a major concern)



Here are my noob questions... If I bed my new DBA 5000 rotors with a set of new OEM pads, drive with them for like 5k miles then decide to put my USED Ferodo pads for the track, do I need to rebed the pads/rotors, and/or should I sand the pads kinda flat every time I do a pad swap on the same rotor?
Can I bed my new rotors with my existing OEM pads? Should I sand those flat?

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osbornsm

I you re-bed the pads / rotors after each change you should be golden. There's no need to sandpaper them, unless you have pad deposits on the rotor.

That's like asking for tires with lots of grip that last for 50k miles. :-(

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DEpointfive0

Thanks for the reply!


And I take it more as, which street tires offer the most grip for the track? RS3's, RE-11's, NT-01's... Something to that effect
Now, which ones offer the most grip without making me go deaf, Michelin PSS's

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BGTV8

I have the DBA T3 front and rear on my Z34 and have used Endless MX72 and Ferodo DS2500 and not experienced any squeal at all. I also have used (track only) Endless ME20 and DS3000 but you would never use them on the road - they will chew a rotor to bits in <50 klics.

I recently tried Project Mu HC+ and they can be noisy when cold.

I have never worried about dust - I use a pressure washer on the wheels after each track day and once every 3-4 weeks to keep the wheel surface clean

Tyres: I have used Kumho KU36 (just "OK"), Direzza Spec 1 and 2 plus RS3.

All these will heat-cycle out when used as DD tyres (they typically lose grip once more than 60% worn unless retained purely to track work). Seems like after 25-30K klicks, they give up their best grip - KU36 was the worst, Direzza the best. The RS3 gave the best track grip, BUT they are fairly soft and anything more that 5 lap runs on the circuits I use they overheat and give up - just get really soggy. I suspect that if you kept charging, you would absolutely kill the tyre. I reckon that the RS3 is worth a couple of 10ths over the others (especially at really hi-speed circuits like Philip Isalnd), but it is a lot easier to totally kill the tyre. Overdo an RS3 and you'll find chunks of rubber flying off the tread and maybe casing failure - that is what I mean by killing the tyre. I have a pyrometer which I use religiously to make sure that the tyre temps don;t go overboard.

That said, best compromise option IMHO is Direzza Ver 2 of the tyres I have tried.


Fro track work, I now run 18 x 9.5 square track setup +22 at front and +12 at rear with 265/35R18 A048R Yoki at front whilst I wear out the 275/35R18 NT01R that I have on the rear for a year or more. I used to run NT01R on the front as well but as 245/40R18 on an 8.5 wheel. I found I was wearing out two sets of fronts to one set of rears, so I went wider on the front to give more grip and sicne I cannot get Nitto here anymore, went to the A048.

Once the NT01 rear is worn out, I will run Yoki's all round until the stocks are exhausted (been replaced here by the A050, and the local Yoki dealer still has a lot of A048 stock left), as I am too tight to pay over the odds for the DZ03G Dunlop R-Spec - they are the quickest tyre but they are the most expensive R-Spec you can by in Oz.

cossie1600

The re11 or even the rs3 are relative quiet when new, quieter than the stock re050a. Problem is that now they are bald, my car does like 83db at 70mph.

DEpointfive0

BGTV, rep'd


Thanks for the info! I actually have a set of Ferodo DS2500's that are used that were going to be "track pads"

Can I bed new rotors with the used pads? Or is that not recommended because the pads will groove the rotors differently? (I know the rotor is stronger than the pads, but still)



(And this wasn't meant to turn into a tire thread, lol, that was just my example)

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cossie1600

Your car can only stop as fast as your tires. You put these aggressive pads on, you will get better feel, but actual distance won't improve much

DEpointfive0

this is something I tell people as well.
Your braking is usually limited by your tires, because as soon as your brakes lock up, they aren't doing anything, and it's all dependent on your tires

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BGTV8

I always use old pads to bed new rotors, and old rotors to bed new pads (unless they are Project MU which do not need bedding, just a few hard stops to make the pad "conform" to rotor shape).

The DBA rotors need to get sufficiently hot to change the colour of the first 2 paints and that can be done by finding a quiet road, driving at 55-60mph and doing a maximum rate stop down to 30mph, speeding up to 60 again and repeating the process 10-15 times (cease after 10-15 stops or as soon as you can "smell" the brakes). Then drive for 20 minutes without using the brakes unless you have to, and then only use the brakes "gently" - to let the rotors cool - they need to be cool enought to touch at the finish by the time you stop the car.

This gives the rotor a heat cycle and conditions the friction surface for best longevity. A brand-new rotor taken straight to the track and flogged risks cracking due to thermal stress/shock.

Another method is to cold-fire the rotor (rotors chilled in liquid nitrogen and then permotted to come up to air temperature over 12-15 hours). I use the guys in the URL below but since they are in Melbourne, it is going to be a problem for you ... but at least you will get the idea of the service they offer.

Cryocycle - Home

Lots of people reckon this is a dark-art and BS, but my experience is that it works, both on my race car and in the Z34.

The other thing about more aggressive pads is that what you are doing is improving pad friction which will have some (modest) effect on stopping distances, but more importantly, these pads will dramtically improve the braking systems resistance to heat. The type of pads being discussed are substantially more heat-resistant and the brakign system will work consistently over a longer period without showing signs of stress (eg: brake fade and extended stopping distances with hotter rotors and pads).