Drilled/slotted or smooth rotors?

[VIKING_MECHANIC]

For the burb, I've kept it oem. I was thinking of one day trying slotted rotors . However oem has worked fine for 474kmiles

474K? Damn! I may be catching up...424K as of Friday!

 

[Frank Enstein]

A rotor with a surface interruption (slots, & etc.) help evacuate the outgassing from the brake pads when they get hot.

That used to be a big issue but no more. Modern pads don't outgas much at all.

They can sometimes run a bit cooler reducing warping slightly due to their increased surface area, and in the case of holes air can be pulled through the holes dropping the temperature further. This is a small effect at best.

 

[df2x4]

My two cents as someone who's run both on these trucks... Stick with standard blank rotors.

I bought a set of high dollar EBC dimpled/slotted rotors to run with the aggressive Raybestos EHT369H pads on my Suburban, thought process being that the extra cooling would be beneficial and help keep me from warping the rotors. Well, less than 10K miles later those dimpled/slotted rotors were warped beyond repair. I went back to smooth rotors and if anything the brakes feel like they grab even harder than before.

IMO on a race car that's turning multiple laps on a road course at speed, sure, the extra cooling from a slotted rotor might help things live longer. On one of these trucks that's primarily street driven, you'll get better panic stop performance from a blank/solid rotor that has more material making contact with the pads. And in my experience, they'll probably last longer.

 

[df2x4]

One other point, drilled or slotted rotors can be a pain to turn if they're out of round. It's possible, but not all shops will want to. Sticking with smooth rotors will simplify any necessary maintenance.

 

[Schurkey]

That's what I'm figuring, but I imagine they have a use, otherwise they wouldn't exist - right?

The primary purpose of MOST drilled/slotted rotors is to provide enhanced profits to the importers and retailers.

They're often the same as cheap-junk white-box rotors but they've been thrown onto an automated milling machine, and then dropped into a fancy box, with the price jacked-up.

 

[Erik the Awful]

Drilled and slotted rotors are big in racing for several reason. Primarily dissipation of heat and weight reduction.

I am not a fan of drilled rotors, they have a tendency to crack between the holes. Slotted rotors are fine if you can find any that aren't also drilled.

So in summery plain old stock rotors are great for our trucks.

A rotor with a surface interruption (slots, & etc.) help evacuate the outgassing from the brake pads when they get hot.

That used to be a big issue but no more. Modern pads don't outgas much at all.

They can sometimes run a bit cooler reducing warping slightly due to their increased surface area, and in the case of holes air can be pulled through the holes dropping the temperature further. This is a small effect at best.

IMO on a race car that's turning multiple laps on a road course at speed, sure, the extra cooling from a slotted rotor might help things live longer.

The primary purpose of MOST drilled/slotted rotors is to provide enhanced profits to the importers and retailers.

Drilled and/or slotted rotors do almost nothing for heat dissipation nor weight reduction. Frank's got it right. Old pad materials created gases when hot, and the gases boiling out of the pads limited the clamping force you could exert. The holes and slots gave those gases an escape route. Modern pad formulas don't have an outgassing problem.

Drilled/slotted rotors are terrible for cracking and warping. I'm sure somebody will pop on here and comment they have 100,000 miles on their boy-racer slotted rotors and they're still like new. Good for them. Most of them only last for one set of pads.

For racing, they're still mostly junk. If I remember right, my race team has drilled/slotted rotors on our BMW, but brakes are budget-exempt, so they're probably ungodly expensive Bimmerworld pieces. Many endurance racing teams have found that solid rotors last significantly longer with no loss in performance. Buying good pads matters more.

Most of the drilled/slotted rotors out there exist simply to separate hard working enthusiasts from their paychecks. As someone who's actually raced wheel-to-wheel on a road course, drilled and slotted rotors don't impress me. It might be that bit that gets you a trophy at a car show though.

 

[SUBURBAN5]

474K? Damn! I may be catching up...424K as of Friday!

Not original miles but the braking system has been stock setup. Only modified components are ss brake hoses.

 

[62barsoom]

I wish I'd read this thread sooner. Living in the mountains and hauling firewood to heat the house, I bought into the hype. Parts are still in the barn waiting for the snow to be done and it's to late to send em back.

 

[Frank Enstein]

Run 'em. They're fine. I put a set on the wife's Astro. No problems.

 

[Erik the Awful]

I wish I'd read this thread sooner. Living in the mountains and hauling firewood to heat the house, I bought into the hype. Parts are still in the barn waiting for the snow to be done and it's to late to send em back.

If you already have them, run them. Just check for cracks whenever you have a wheel off. When you replace pads, do a thorough inspection.