What is the difference between all brake rotors?

Question

What is the difference between regualr brake rotors, slotted, and drilled rotors? Which do you recommend and can you paint them?

Answer 1

Older brakes rotors used to be made out of solid iron. Friction from the pad surfaces would transfer into the rotor. These types of rotors have poor thermal performance and are easy to send into brake fade. Most modern rotor these days are vented. They are hollow with an array of internal fins resembling that of a centrifugal impeller. As the rotor spins, air is sucked in from the middle and discharged out at the perimeter. This additional movement of air helps cool the rotors. Slotted and crossdrilled rotors are intended for high performance applications. Crossdrilling was done initially not for cooling, but to vent gases generated by the brake pad during extreme braking. Modern pads don't offgas, so there is less of a need for crossdrilling these days. Crossdrilling also increases the surface area of the brake rotor by allowing it to transfer absorbed heat into the air faster than an undrilled rotor (at a cost of reducing its heat storage capacity). Crossdrilled rotors are also lighter, and the reduced rotating mass will cause a slight improvement to both accelleration and braking. The downside of crossdrilled rotors is that the holes are prone to cracking, and some machine shops may refuse to service them. Slotted rotors are capable of venting gases much like crossdrilled rotors. Due to the shape of the slots, slotted rotors have the ability to resurface the pads everytime the brakes are applied. The net result of this is a slighty shorter service life for the pad, but more consistant wear between the pad and the rotor (the slotted rotor has less of a chance of developing score marks than other types of rotors, this might be very valuable to you if you plan on frequently changing brake pads for racing events).

The choice of which type of rotor to install depends on how the vehicle is used. Most street cars will work fine with standard vented rotors. Brake perfomance can be improved by installing high performance brake pads. Your brake fluid should be purged every few years as well (running a fluid with a higher heat capacity is a good idea too, but check the chemical compatibility first) You may wish to explore slotted and/or crossdrilled rotors if your stock rotors are under performing in track application. If your brakes are seriously incapable of delivering the stopping power you need, you should look into a big brake kit. Stainless steel brake lines help improve brake feel (they take out the spongy rubber brake lines), but don't actually contribute to extra braking power. The internal teflon liner in stainless lines also wears away from road grit, so you should replace them every few years as well.

Answer 2

There are 4 types of rotors: solid, ventilated, slotted and drilled. All can be painted, but only on the hubs.

Solid is what you find on rear discs. It's just an iron disc. Simple, huh?

Ventilated is what you commonly find on front discs. Its actually 2 discs with metal fins separating them, so that air can pass through the disc from the centre to the edge and help it cool down.

Slotted discs have grooved machined into the disc face. This aids in keeping the disc and the pad clean and dry (the grooves scrape the water off the pad), and gives the pad a little more bite, since the friction area isn't completely smooth.

Drilled is similar to slotted, but it also makes the disc lighter. This aids handling by reducing your unsprung weight, but also means that there is less metal there to take the heat generated when braking. They also have a tendency to warp, because they heat up too fast, and then cool too fast. Some also claim better off-gassing from the pads, but most pads don't have gassing problems these days. Some also claim better cooling, although holes in the rotor just mean that cooling air can come out of the holes instead of making it all the way to the disc edge, like a regular ventilated disc would do.

Generally (except for a few sports cars), drilled rotors are only truly effective on race cars - they can take the heat (since racers aren't on the brakes for very long) and the brakes never really get a chance too cool down all the way before the next corner, anyway - so they don't get a chance to warp until after the race. Besides, they can afford to change then after each race. it's a compromise they're willing to accept, but I wouldn't suggest them for the road. Slotted is your best bet for all-round performance and longevity.

Answer 3

Regular brake rotors are just plain rotors, two sided usually with fins between the sides to aid cooling. Slotted and drilled rotors use slots or holes machined into the braking surface of the rotor to aid heat disappation and shorten stopping differences.

Unless you have a high performance car, normal rotors work just fine and the other kinds are mainly for looks.

Calipers are often painted anymore but to paint the rotor itself is kind of a big waste of time. Paint isn't going to like the intense heat and you can only paint the hub part of the rotor anyway.

Answer 4

Do not fall for drilled rotors. After a couple of thousand miles they tend to propagate cracks around the drilled holes because of stress risers during heating and cooling. Slotted rotors are best for street use. Race rotors are another story. Bolt on rotors are bolted to brake hats. At all costs do not buy cheap - off shore rotors (Chinese). Metallurgy is very sub standard. Annealing heat treat is not documented and they last a year or two if your Lucky. American, Canadian and British products are up to snuff.

Answer 5

i own a repair shop,and regular brake rotors heat up a lot faster and cool down a lot slower,anything with holes or slots in it will stop better and cool down a lot better also,and this means better stopping power for any car that there on and they also last longer than other rotors do,good luck i hope this helps.,,PS id recommend these over stock rotors any day,good luck.

Answer 6

Slotted have groves cut int them and drilled have holes drilled into them.

no you cannot paint disks the metal surface is what rubs against your brake pads to stop you, paint would be peeled off the first time you stopped.

drilled and slotted offer more surface area for cooling.

Answer 7

slotted and drilled are for cooling purposes..hi perf cars use slotted and have air aimed at them to help cooling..you cannot paint rotors..calipers,yes..and your rear drum brakes can be painted(not inside tho'

Answer 8

Just curious to see how long it will take to catch up to Doge Man