bored and slotted rotors?

**Matto4785** · 04-22-2006, 03:58 PM

Whats the difference between bored and slotted rotors, and crossdrilled and slotted rotors? I've seen pics of them, and the only differene i can see is with the bored rotors, the holes look to be chamfered quite a bit more than the drilled ones. Other than that, is there any difference between the two?

**low_dreams** · 04-22-2006, 09:20 PM

Not really.

Brakes actully work better undrilled/bored and un/slotted. Wierd fact, huh.

I will find a link to post if anyone disagrees.

Slotted rotors are not desireable because as you're on the brakes the slots act like 'razor blades' cutting through your pads. They don't last long, and unless you have metallic pads with slotted rotors, your wheels will NEVER be clean.

Cross drilled rotors claim to cool faster, but they take away from brake surface, That's why it's better to have a solid rotor. They don't really cool much faster, if at all. I don't think they to at all. The holes are too small to do any good, if they were big enough to do any good, big enough to actually allow air to mosey through them, you wouldn't have any stopping surface left.

Though for cosmetics they are nice to have. They look good.

I like cross drilled rotors. Never slotted, it's simply throwing your money in the trash. IMO.

**Matto4785** · 04-22-2006, 11:01 PM

They do look good, though, for the cracking issues that people have, i dont think the look is worth it. I may look into getting dimpled rotors like Powerslots Prostops.

Here's the pic of the two, so you can see the difference, if anyone is still interested.

normal crossdrilled:

bored and slotted:

Mods, these are the only pics i can find, if they aren't allowed because of the watermark, feel free to take them off.

**SGTGearHead** · 04-23-2006, 01:21 AM

Originally Posted by low_dreams

Not really.

Brakes actully work better undrilled/bored and un/slotted. Wierd fact, huh.

I will find a link to post if anyone disagrees.

Slotted rotors are not desireable because as you're on the brakes the slots act like 'razor blades' cutting through your pads. They don't last long, and unless you have metallic pads with slotted rotors, your wheels will NEVER be clean.

Cross drilled rotors claim to cool faster, but they take away from brake surface, That's why it's better to have a solid rotor. They don't really cool much faster, if at all. I don't think they to at all. The holes are too small to do any good, if they were big enough to do any good, big enough to actually allow air to mosey through them, you wouldn't have any stopping surface left.

Though for cosmetics they are nice to have. They look good.

I like cross drilled rotors. Never slotted, it's simply throwing your money in the trash. IMO.

Another keyboard certified mechanic

Here's my experience with rotors. Bought my car new in Nov 98. After 13k miles; stock rotors were warped horribly. I had them turned; warped again after 5k. Replaced them with Power Slot rotors, front and rear. I had slotted front rotors on the car for 85k miles. I wore out 2 sets of pads on those things before they finnaly started to warp. I swapped the fronts out with Power Stop units ( Drilled AND Slotted.)

I have 130k miles on her now and the rear Power Slots are still going strong.

The only down side to slotted rotors is you're not supposed to turn them. My best guess is you'll grind out the slots, duh!
Like anything else, YOU GET WHAT YOU PAY FOR. Don't get the cheap shit off E-BAY
BTW, cheap pads make your wheels dirty not slotted and drilled rotors

CARRY ON!

**Eugenio_SS** · 04-25-2006, 04:36 AM

Originally Posted by SGTGearHead

Another keyboard certified mechanic

Here's my experience with rotors. Bought my car new in Nov 98. After 13k miles; stock rotors were warped horribly. I had them turned; warped again after 5k. Replaced them with Power Slot rotors, front and rear. I had slotted front rotors on the car for 85k miles. I wore out 2 sets of pads on those things before they finnaly started to warp. I swapped the fronts out with Power Stop units ( Drilled AND Slotted.)

I have 130k miles on her now and the rear Power Slots are still going strong.

The only down side to slotted rotors is you're not supposed to turn them. My best guess is you'll grind out the slots, duh!
Like anything else, YOU GET WHAT YOU PAY FOR. Don't get the cheap shit off E-BAY
BTW, cheap pads make your wheels dirty not slotted and drilled rotors

CARRY ON!

another certified internet user putting others down.
he's maybe not a certified mechanics, but he got lots of facts out.
if you were to take the exact same rotors as you took, but instead had them non-drilled and non-slotted, you would actually brake better and have less heat issues when braking hard repeateadly.
Removing mass and contact area is a double losing combination when it comes to braking... but i guess you prefer sacrificing safety in the name of bling.

**low_dreams** · 04-26-2006, 09:58 AM

Originally Posted by SGTGearHead

Another keyboard certified mechanic

Here's my experience with rotors. Bought my car new in Nov 98. After 13k miles; stock rotors were warped horribly. I had them turned; warped again after 5k. Replaced them with Power Slot rotors, front and rear. I had slotted front rotors on the car for 85k miles. I wore out 2 sets of pads on those things before they finnaly started to warp. I swapped the fronts out with Power Stop units ( Drilled AND Slotted.)

I have 130k miles on her now and the rear Power Slots are still going strong.

The only down side to slotted rotors is you're not supposed to turn them. My best guess is you'll grind out the slots, duh!
Like anything else, YOU GET WHAT YOU PAY FOR. Don't get the cheap shit off E-BAY
BTW, cheap pads make your wheels dirty not slotted and drilled rotors

CARRY ON!

Idleness and dissipation breed apathy.

CARRY ON!

**ErikElvis** · 05-05-2006, 08:36 AM

I love the powerslots. I didnt want to deal with the crossdrilled. On my old car a quick romp on the backroads would leave me with brake fade you wouldnt believe. It was scary. Threw the slots on with better pads and it was a 110% improvement.

**predator** · 05-05-2006, 09:23 AM

Originally Posted by low_dreams

Slotted rotors are not desireable because as you're on the brakes the slots act like 'razor blades' cutting through your pads. They don't last long, and unless you have metallic pads with slotted rotors, your wheels will NEVER be clean.

Cross drilled rotors claim to cool faster, but they take away from brake surface, That's why it's better to have a solid rotor. They don't really cool much faster, if at all. I don't think they to at all. The holes are too small to do any good, if they were big enough to do any good, big enough to actually allow air to mosey through them, you wouldn't have any stopping surface left.

slots allow built up gases to escape (i supposes holes do to) which will keep your rotor from floating... and the holes actually if at the very least add more surface area to the brake which allows the brake to transfer more heat to the air...

and more surface area? WTF... surface area has zero, nada, zilch, zippo to do with friction... its all about weight (edit: i had pressure and thats was about stupid of me because i would be contridicting myself because pressure has to do with surface area) and the coeficent of friction...

i figure i would go with slotted only actually... just because of the cracking issue... but cross drilled do look alot better

-me

**predator** · 05-05-2006, 09:26 AM

Originally Posted by Eugenio_SS

another certified internet user putting others down.
he's maybe not a certified mechanics, but he got lots of facts out.
if you were to take the exact same rotors as you took, but instead had them non-drilled and non-slotted, you would actually brake better and have less heat issues when braking hard repeateadly.
Removing mass and contact area is a double losing combination when it comes to braking... but i guess you prefer sacrificing safety in the name of bling.

and what the hell? removing mass removes interia... making it easier to stop.... y do you think they have aluminum hat rotors?

-me

**Orcus79** · 05-05-2006, 04:02 PM

Originally Posted by predator

and what the hell? removing mass removes interia... making it easier to stop.... y do you think they have aluminum hat rotors?

-me

To a point. Yes less rotaional mass means faster stopping, but the a heat carring capacity of the materail has alot to do with it as well. Sloted and or drilled rotors do yes wheigh slightly less, but its their ability to remove heat that makes them work. The slots and holes allow the gasses generated to escape more rapidly, drilled rotors will cool faster because air can travel more freely through them. The vanes between the two surfaces creat a heatsink and fan effect. For street use the sloted is all you need, the only time you really need drilled ones is for heavy track use where you would be constanly on and off the brakes.

**predator** · 05-05-2006, 05:01 PM

sorry i was trying to make the point you just did... well that and say that eug is needs to stop spreading stupidity...

i wasnt trying to say that the weight is removed for the prupose of stopping faster... i was actually trying to say that if the removal of material has any effect on stopping power it would be positive (actually prolly more effect than you think, rotating mass is bad)...

and that even if cross drilled rotors didnt move air very effectively for a cooling effect... the simple increase in sufrace area would cause a fairly impressive increase in heat exchange...

if i didnt make my points clear sorry i was at work and had to type it up fast...
-me

**LIVINGTHEDREAMLIFE** · 05-06-2006, 01:40 PM

If I Were Going To Upgrade The Stock Rotors, Which Company Would Be At The Top Of The List???

Thanks In Advance,
Chris

**Fastcar** · 05-06-2006, 11:54 PM

All I can say is, do your research and get your facts right! Why don't you actually talk to some people who have no vested interest in selling you a specific product?? I'm running plain blank BREMBO replacement rotors with ceramic pads and with 30K+ miles on this setup (also installed SST brake lines) I've had no problems, rotor warping etc. How many of you torque your lug nuts by hand with a torque wrench? My tire shop does - improper torque will also contribute to rotor warp. STOCK GM ROTORS ARE UNDENIABLY CRAP, THEY'RE NOT MADE WITH A GOOD IRON ALLOY. Most modern brake pads (notably ceramic) don't have outgassing problems - the outgassing is caused by the binder material used to make the friction material of the brake pad. MORE SURFACE AREA = BETTER BRAKING, PURE AND SIMPLE - NO DRILLING, NO SLOTTING. Why do you think Wilwood and Baer make Big Brake kits??? TO GIVE YOU MORE SWEPT AREA, THE CONTACT AREA BETWEEN THE PAD AND ROTOR. And yes, having a larger pad and rotor helps spread the heat load out and gives the rotor more heat adsorption capacity due to the larger size and mass. BTW, the aluminum hat area of the rotor is not actually used for braking: it's used to mount the rotor itself to the hub/lugnuts. Overall lower rotating mass is better, but not by reducing the mass of the actual braking area!!

**LIVINGTHEDREAMLIFE** · 05-07-2006, 06:01 AM

Its Funny You Mention It... I Had Already Made My Mind Up To Go With The Brembos... I've Used Them Consistanly On My Bikes, And Had Nothing But Great Results. I Just Wanted To See If There Were Any Other Companies Which May Have An Advantage For A Resonable Price For Cars.

For This Particular Application Its Mostly For Looks Anyway. The Car Barely Gets Driven.. Its A 2001 With 3,484 Miles. I Just Keep Buying Mods When I Get Extra Cash.... 20 Years From Now It Will Pay Off.

**predator** · 05-07-2006, 06:34 AM

a big brake kits that actually move the pad and so forth out impoves braking because of the moment (i guess would be the best way to put it)... this is like spinning anything and trying to stop it with your fingers near the center (pretty hard to do), but if you grasp it on the edge youll be able to stop it without any problems...

next time you have a tire off the ground barely spin it and try to grab the spoke of a wheel and then try to grab the tread... just dont hang on to the spoke cause you prolly aint gonna stop the wheel...

BTW, the aluminum hat area of the rotor is not actually used for braking: it's used to mount the rotor itself to the hub/lugnuts. Overall lower rotating mass is better, but not by reducing the mass of the actual braking area!!

oh really you mean you dont brake right around the lugs? i thought i had this whole thing figured out... and y wouldnt you want to remove weight in the actually braking area... the further out you can remove the weight the more impact it will make on rotating mass... although having a lighter center section would make a difference... the same amount of weight removed from the outside would make an exponentially greater difference...

braking companies like wilwood or brembo have it all figued out... they know where to it pays off to add a little rotating mass to gain stopping power... they have teams of engineers doing whatever they can to get your car to stop as fast as possible... the only ways to get a car to stop faster is to improve the coeffiecent of friction between the pad and the rotor, move the pad out on the disk, increase line pressure, or remove inertia (either rotational or just mass)... all of this assuming you keep you brakes cool... heat causes rotor warpage, outgassing, and boils the fluid in your lines all causing brake fade...

go with some drilled and slotted rotor (they simply look better) or atleast some slotted one... get better pads and stainless steel lines to reduce line expansion ans some ppl say move up a step in brake fluid (check and make sure it wont react with anything in your system) to reduce boiling and go make abs go crazy...

oh and some of you ppl need to take a looksy at this... linky

-me

**jmhvenom** · 07-26-2006, 06:13 AM

Slotted and drilled makes less surface are, it will not change the force but the pad will be exerting more pressing on rotor causing more stress. Rotating inertia, I dont think any pads/rotors have a problem stopping the mass of the wheel. You can lock up your brakes going most speeds with a firm press of the peddle. Now, I cant say that is the best way to stop lol.

**Wulfe13** · 07-26-2006, 09:54 AM

Ok.... I AM an ASE certified Master Mechanic/ Master Machinist, so listen closely...

Drilled rotors cool down faster and more evenly than non-drilled. That's why damn near ALL race cars use them!
Slotted rotors allow gases to escape to help eliminate brake fade.

They DO NOT chew up your brakes faster! I've had mine on for 30k and I still have half my pads left... I stop BETTER than stock and I only changed the rotors, everything else is the same... Cracking? Nope... Warping? Nope... Dirtier Wheels? Nope actually cleaner now... go figure...

The amount of surface area removed by drilling a rotor is not near enough to "hurt" performance... it DOES help cause of less rotating mass...and Brakes work better when they are warm NOT red hot!

Oh and I did buy the cheap eBay rotors... drilled/slotted and zinc washed... and they were dirt cheap...

**Wulfe13** · 07-28-2006, 09:12 PM

http://www.ws6project.com/user_stor/...f263c2a4ddce83

I think these are the exact same ones I bought... and they're a sponsor... and you can't beat THAT price!