Rotors that don't warp?

[shadow191]

He's not wrong, but you're not wrong either. Holes whether cast or drilled can result in rotors more prone to cracking. Most OEM drilled rotors are cast with holes like Porsche and their rotors do crack sometimes. Almost all aftermarket rotors are drilled from blanks and the chances of cracking will depend on how the work is done. These days, the chances are far less since they typically chamfer the holes to reduce the stress risers. This wasn't always the case, I had Brembo's over a decade ago and their holes were not radiused at all.

I've personally never had an issue with any of the drilled rotors I've had over the years, but I know people that have. No one's ever had a rotor totally fail, but I've seen some with cracks starting around the drilled holes. And parts choices for racing are different than parts choices for street cars. Just because a rotor doesn't fail during racing doesn't mean it's not more prone to fail on a street car. In racing, you're not doing a bunch of start/stops or driving through a car wash with hot brakes, etc. Plus I doubt you expect your rotors to last tens of thousands of miles. And if you want to see pictures of cracked rotors from racing, just look at Porsche's. There are quite a few pics of GT3 rotors cracking at the track. Still not common, but it does happen.

In theory, drilled rotors are weaker than non drilled and more prone to crack. Basically you've removed material and introduced areas of potential stress. In practice, there are a lot more factors.

 

[SCY7H3]

Not to say that your experiences are not actual but you have to consider the variables at play. Its quite easy to overlook the reasons why you had a great run at cross drilling rotors.

What brake setup are you using on the cars/bikes that you are racing? Quality and design dictates tolerance levels. Also if you've done this for years, you've probably realized that quality levels have come down as long as they meet regulations.

Back in the good days, quality was much higher than required by law so you could alter the hell out of something and it would be able to tolerate it. Today quality is at a hairline above regulation. So if members like us who buy Infiniti's and drive them a bit more aggressive than a typical person would, that's considered by the dealer as "going outside of the limits". This is the official stance from the manufacturer's head office. It's a bad excuse but its due to manufacturers trying to save on production and make more on servicing vehicles.

So unless a car like a GTR or a Corvette or something that is designed with tons of power, that's the only way you're getting that quality to meet the demand of the vehicle as required by regulation.

There are however third party brands with higher quality levels but you pay for it but you also have to know who those are. Some are wannabes and some are legit. And even if a certain brand had "outstanding" quality during their first years, they all eventually outsource to cheaper production with the odd defective part.

I have personally had rotors drilled myself back when I had a turbocharged Supra and there were two factors at play. First factor was quality of the rotor, second was the quality of the workmanship of drilling them. Having a high quality rotor with poor workmanship will not cause you issues as the tolerances of the rotor are higher. But if you throw in a cheap rotor with bad workmanship of drilling them, you're playing Russian Roulette.

There's so many variables at play today which contribute to the mass confusion people have as noticed here in this thread. One member same car same setup same driving style drove on a set of rotors for 80k while another only drove for 23k.