Rotors, please explain the difference
 

Could someone please explain why when purchasing rotors some will get cross drilled some will get slotted and some will get the combo. I ask because I intend to change my rotors in the near future and need to be educated before making a purchase.
Thanks in advance,
Tom

Cross drilling and slotted rotors is b/c it gives the gas/brake dust an area to escape kind of like a passage most people buy them cause of the looks but if it is cross drilled and slotted it will release heat quicker than stock.

Hope some of this helps.

Yes that I do understand, I actually have them on my FX, but to be honest I did it for the looks. So I ask this, then why do they offer an option if the combo is the best way to go. I also notice that not all race cars use just the cross drilled /slotted. I have seen all 3 types out there

I'm not exactly sure but by having them cross drilled could also be for lightening to keep reciprocating mass down but having all of them would give the most benefit,slotted is generally to get rid of expanding gases but does also keep weight down too.

Thanks for the info. :tiphat:

It's all for looks on a street car, makes no different when you drive from IKEA to Home Depot

There are more reasons. To touch on all I can think of:

1) aesthetics
2) weight reduction (though minor)
3) ventilation (minor)
4) increased initial bite...this is a big draw for the slotted rotors

Keep in mind that drilled rotors may crack under high temperature applications. From what I've read, the best overall braking force is obtained with non-drilled, non-slotted rotors. Slotting and drilling can both increase pad bite by shaving off the brake pad surface and exposing fresh material.

The car will be at the track this summer for sure.

Considering the heat issues the 370Z has with brakes, you shouldn't do either one - having more mass provides more heat sinking for the discs.

And what are the heating issues with the brakes ? Wouldn't the drilled holes
or slots make the weight lighter (slightly) ? The drilling and slotting would also release the hot gas therefore making the rotors/pads cooler..?

Just curious..

Cross drilling give the rotor more surface area, which in turn helps the rotor cool down more quickly. Slots on the other hand gives the pads a way for the gases from the pads to escape. Also it shaves the pad surface as your braking, letting the contact surface of the rotor and pad to be fresh and help prevent hazing.

But here is the real deal with them.
Current pads do not release a gas. So slots for that purpose is deemed useless. Now I do get the slots to resuface the pads but its just a placebo effect for me (I just like looking cool)

The cross drills on the other hand may actually work. but the tradeoff is much worse. This is why I stay away from crossdrilled rotors and so should you guys. Cross drilled rotors are very prone to cracking. In fact one session at a track day is all it takes for them to really crack.

I am not saying none of the other rotors crack. In fact most my rotors crack because of the aggressive pads I use on the track. But Cross drilled rotors are just plain scary how easily they crack. Also just to get the information straight for you guys, neither crossdrilled or slotted rotors are made to save weight. The better more performance oriented crossdrilled rotors have double the number of veins inside the rotor to not only strengthen them, but also to further help with cooling, causing the rotor to be even heavier than the stock.

Hope this helps.

Would cross drilled and slotted be ok for daily driving..? I don't have any plans of tracking the car..

Yes, you'll be fine for street driving. The stress cracking only occurs from the heat cycling at the track.

Thanks for the reply.


I would be in it more for the aesthetic aspect of the brakes..

Yes you'll be fine for dd. I generally put on slotted rotors for dd. But again this is also more prone to cracking than the stock blanks.