Opinions on drilled and slotted rotors

JP

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#16
Question from a shade-tree, what does slotting the pads do?
 

nickb2

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#17
It helps eliminate brake fade due to trapped brake gasses and debris caused by pad and rotor wear, hence, allowing debris to escape and not become part of the pad rendering it noisy and pitted etc, but mostly allows for expansion due to heat which prevents the pads from cracking.

For heavy applications, I will slot two groves with a hack saw for each pad, but normally one slot vertically or diagonally does the trick.

The chamfer on the ends helps reduce noise and add better engagement.

So sometimes, you can cheap out a bit on a set of pads and modify yourself cus if the company didn't do that, they can sell them cheaper since they didn't have to go through the extra finishing details.

But usually a high end pad has better bonding glue, adds in new hardware and some grease and normally has quality pad noise reducing shims already riveted or glued to the back side.

If you buy a set of pads and it has no hardware, no shims, you can bet those pads will suck large from the start.
 

big al

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#18
I got the rotors, there is a difference in weight and feel to them. They feel much more heavy duty and sturdier than ac delco rotors (sound strange but sometimes you can just feel a difference). And the pads already have 2 deep grooves in them. Ill get them on in the next few days and see how they do, im not expecting much change as i dont drive this car like i stole it. Im just hoping the shake will be gone and stay gone for more than 1.5 years.
 

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cw41

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#19
It helps eliminate brake fade due to trapped brake gasses and debris caused by pad and rotor wear, hence, allowing debris to escape and not become part of the pad rendering it noisy and pitted etc, but mostly allows for expansion due to heat which prevents the pads from cracking.

For heavy applications, I will slot two groves with a hack saw for each pad, but normally one slot vertically or diagonally does the trick.

The chamfer on the ends helps reduce noise and add better engagement.

So sometimes, you can cheap out a bit on a set of pads and modify yourself cus if the company didn't do that, they can sell them cheaper since they didn't have to go through the extra finishing details.

But usually a high end pad has better bonding glue, adds in new hardware and some grease and normally has quality pad noise reducing shims already riveted or glued to the back side.

If you buy a set of pads and it has no hardware, no shims, you can bet those pads will suck large from the start.
Hello nickb2, I've been using Max Brakes out of Ontario for the last few brake jobs and they seem to be a bit better than any oem/atermarket i've used. I use the elite series which have the 3500 gray iron content, most all others are in the 2500-3000 grade. They are drilled and slotted. But I do highway driving so thats easier on them. Rotors and pads for 75.00 us cash makes them cost effective to change out every two years or so. I've done the police options on Impala's and Charger/Chrysler and still no good, at least for me. Brand doesnt seem to matter they all warp.
 

cw41

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#20
I got the rotors, there is a difference in weight and feel to them. They feel much more heavy duty and sturdier than ac delco rotors (sound strange but sometimes you can just feel a difference). And the pads already have 2 deep grooves in them. Ill get them on in the next few days and see how they do, im not expecting much change as i dont drive this car like i stole it. Im just hoping the shake will be gone and stay gone for more than 1.5 years.
Weigh yourself on a scale holding your old rotor and then with the new. I've found the weight to be the same. Thats if you dont have a a/c scale for freon that is easier and more accurate. Even the brakes I use now weigh the same, give or take an ounce.
 

PC

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#22
Back in the 60s and 70s we were stopping some pretty heavy boulevard barges with the brake technology of the time which usually consisted of heavy vented front rotors and usually rear drums. Generally rotors were only replaced if all chewed up and they didn't turn into a pile of rust in 2 years. I have a nearly 50 year old GM vehicle with original rotors and they still look good and the brakes don't pulsate. Now, I'm no metallurgist, but I think the quality of iron has something to do with it along with the pad material available today. Granted all we had back then was organic/asbestos, or semi-metallic pads, nothing fancy. My thinking is drilling the rotor reduces the braking surface area and creates stress points, sure race cars have drilled rotors, but they also have air ducts to cool the rotors and don't need to make panic stops stressing the rotor even more. I'm currently dealing with the rear brakes on a Fusion. Used a well known old school brand of pads and rotors which were total garbage, lasted less than 10K mi. Just installed a set of Centric Posi-Quiet pads and their coated rotors, no noise, no dust.
 

big al

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#23
PC, i agree with you. I have classic Monte Carlo, Trans Am, Skylark sportcoup, 1951Chevy Styleline Deluxe, and a Henry J. These classics are all still using old rotors and drums that have seen lots of miles and some extremly hard braking sessions as we enjoy these classics randomly at times. And these old rotors and drums hold up really well even on the boulevard barge such as the 64 buick skylark and none of them shake,pulsate or any other b.s. although they no longer need to worry about rusting. I agree with the idea that metals today are not what they were then. Anyways i didnt weigh the rotors on a scale (wish i would have thought about that) but rather just one in each hand and noticing the difference. (I would bet the new ones weighed more, sure felt like it). I installed all 4 along with pads and brakes are smooth again, no noise(some said they make extra noise), no extra brake dust on wheels. How long they will last? - only time will tell. Now this impala is a work/comuter car so it doesnt see the exciting drives that my (Toy) cars see randomly.