Pad/Rotor Replacement? Should I go Drilled/Slotted.

[edyvw]

In the most basic sense, it does weaken it. it interrupts grain, adds stress risers and can become a shear ledge ( chamfering wont stop that).

Same thing it does on the big breaks on conveyors ( same thing just 2 ft or better diameter)

I can see the need and benefit for a race car but question the legitimate performance add to a regular driver. ( don't question it aids in cooling and possibly some cleaning and grabbing but is it really to the point where a tangible benefit is realized that's significantly better if they were standard rotors?)

There is no any benefit for regular drivers.
Regular driving is all about cold performance. I have elementary school 200 yards from my house, and brakes are and should be designed to operate at maximum there while dead cold. That requires pad material that has excellent cold performance, but same pad material does not have such good performance at high temperatures (above 500 degrees). Regular rotors are perfectly fine in that environment, and if brakes are overwhelmed first weak point is pad, than fluid and than , much later rotor.

 

[TiGeo]

There is no any benefit for regular drivers.
Regular driving is all about cold performance. I have elementary school 200 yards from my house, and brakes are and should be designed to operate at maximum there while dead cold. That requires pad material that has excellent cold performance, but same pad material does not have such good performance at high temperatures (above 500 degrees). Regular rotors are perfectly fine in that environment, and if brakes are overwhelmed first weak point is pad, than fluid and than , much later rotor.

I was surprised even with the EBC Redstuff vs. OE pads in the cold/winter/sub-30 temps....first stop sign I hit leaving my neighborhood was a shocker!

 

[TiGeo]

In the most basic sense, it does weaken it. it interrupts grain, adds stress risers and can become a shear ledge ( chamfering wont stop that).

Same thing it does on the big breaks on conveyors ( same thing just 2 ft or better diameter)

I can see the need and benefit for a race car but question the legitimate performance add to a regular driver. ( don't question it aids in cooling and possibly some cleaning and grabbing but is it really to the point where a tangible benefit is realized that's significantly better if they were standard rotors?)

This isn't always about what you need...it's about what you want. Yes, for daily driving average folks, blank rotors are the way to go as they are 1) cheaper 2) last longer 3) perform. Do drilled and/or slotted rotors look cool to some folks? Yes. Do they help clear water etc. better than blanks? Yes. Does that justify accepting the downside (cost, noise, shorter life)? That is a question those folks need to answer. They are not dangerous for a daily driven vehicle as is evidenced repeatedly in this thread by examples of OEMs including them on their performance vehicles (AMG, BMW, etc.).

 

[edyvw]

This isn't always about what you need...it's about what you want. Yes, for daily driving average folks, blank rotors are the way to go as they are 1) cheaper 2) last longer 3) perform. Do drilled and/or slotted rotors look cool to some folks? Yes. Do they help clear water etc. better than blanks? Yes. Does that justify accepting the downside (cost, noise, shorter life)? That is a question those folks need to answer. They are not dangerous for a daily driven vehicle as is evidenced repeatedly in this thread by examples of OEMs including them on their performance vehicles (AMG, BMW, etc.).

OE drilled rotors are not in the same price range with aftermarket.
Here people mentioned Porsche rotors, BMW M, AMG etc. Compare price of those OE rotors with aftermarket which are usually around $80 to $100 depending on application. For example for 2014 M5, front rotor (one not pair) is around $500, regular steel, not carbon/ceramic.
There is a reason for such high price.

 

[ABN_CBT_ENGR]

This isn't always about what you need...it's about what you want. Yes, for daily driving average folks, blank rotors are the way to go as they are 1) cheaper 2) last longer 3) perform. Do drilled and/or slotted rotors look cool to some folks? Yes. Do they help clear water etc. better than blanks? Yes. Does that justify accepting the downside (cost, noise, shorter life)? That is a question those folks need to answer. They are not dangerous for a daily driven vehicle as is evidenced repeatedly in this thread by examples of OEMs including them on their performance vehicles (AMG, BMW, etc.).

I agree 100% without any reservation and I imagine everyone on this board has their own "pet" thing- personal choice goes without saying.

I was simply addressing it from the other perspective.

 

[ABN_CBT_ENGR]

There is no any benefit for regular drivers.

I didn't think so but was cross checking. Wanting them is fine.

 

[4WD]

In the most basic sense, it does weaken it. it interrupts grain, adds stress risers and can become a shear ledge ( chamfering wont stop that).

Same thing it does on the big breaks on conveyors ( same thing just 2 ft or better diameter)

I can see the need and benefit for a race car but question the legitimate performance add to a regular driver. ( don't question it aids in cooling and possibly some cleaning and grabbing but is it really to the point where a tangible benefit is realized that's significantly better if they were standard rotors?)

I would think so in the like for like case. With extreme rust on my OEM rotors - had wall loss and contamination. When shopping for coated rotors many were slotted/drilled … but on one brand the plates were noticeably thicker so gave them a try. Three good years of safer towing and no visible wear (OEM had grooves in that same period) even with more aggressive pads … No rust.
I did no material comparison so felt lucky they were better than expected … thinking the aftermarket company made the plates thicker to offset the holes/slots. As for looking cool ? My rims had six wide spokes and discs were not really on display …

 

[4WD]

Drilled and or slotted will cause noise when braking. It also reduces the mass of the rotor which is one of the characteristics that makes a rotor better. More mass means less heat rise. Also makes it more difficult to machine. It is purely for looks. Basically it means several drawbacks, with no benefits.

None of that was true for me.

 

[TiGeo]

None of that was true for me.

I haven't had any negatives yet on 3/4 of my cars with some version of these. So this post seems to have several that have actually used the products in question with positive results and the rest that have never used them but telling us all how ****ty they are. Got it.

 

[mightymousetech]

I haven't had any negatives yet on 3/4 of my cars with some version of these. So this post seems to have several that have actually used the products in question with positive results and the rest that have never used them but telling us all how ****ty they are. Got it.

Used them 30 years ago when I was a teenager. Have learned since then. Having been involved in racing for 30 years now, nobody uses cross drilled or slotted brakes on a race car, unless they came that way from the factory. Friend of mine almost died when he thought using cross drilled rotors on track was a good idea. Large chunk of rotor came off, caliper piston locked into the gap and instantly locked the wheel. Flipped the car end over end 3 times.

Taking a perfectly good rotor and drilling holes in it is a bad idea.

 

[TiGeo]

Used them 30 years ago when I was a teenager. Have learned since then. Having been involved in racing for 30 years now, nobody uses cross drilled or slotted brakes on a race car, unless they came that way from the factory. Friend of mine almost died when he thought using cross drilled rotors on track was a good idea. Large chunk of rotor came off, caliper piston locked into the gap and instantly locked the wheel. Flipped the car end over end 3 times.

Taking a perfectly good rotor and drilling holes in it is a bad idea.

We are talking about daily driven street vehicles here...

 

[2EHA]

We are talking about daily driven street vehicles here...

You can get your brakes red hot on the street no problem.

 

[UG_Passat]

OE drilled rotors are not in the same price range with aftermarket.
Here people mentioned Porsche rotors, BMW M, AMG etc. Compare price of those OE rotors with aftermarket which are usually around $80 to $100 depending on application. For example for 2014 M5, front rotor (one not pair) is around $500, regular steel, not carbon/ceramic.
There is a reason for such high price.

The reason for the high price is curved vane rotors are more expensive to produce than straight vanes. Even the aftermarket Zimmermans are not in the $100 range, they do cost less than the BMW packaged part.

The made in China Stoptechs costs more than the BMW packaged part.

BMW F10 M5 S63 4.4L Brake Rotors - ECS Tuning

www.ecstuning.com

BMW Brake Rotors & Discs for BMW 5 Series F10 (2011-2016) | Turner Motorsport

Shop our wide selection of BMW Brake Rotors & Discs for your BMW 5 Series F10 (2011-2016)

www.turnermotorsport.com

 

[ABN_CBT_ENGR]

I would think so in the like for like case. With extreme rust on my OEM rotors - had wall loss and contamination. When shopping for coated rotors many were slotted/drilled … but on one brand the plates were noticeably thicker so gave them a try. Three good years of safer towing and no visible wear (OEM had grooves in that same period) even with more aggressive pads … No rust.
I did no material comparison so felt lucky they were better than expected … thinking the aftermarket company made the plates thicker to offset the holes/slots. As for looking cool ? My rims had six wide spokes and discs were not really on display …

True and as we both know, pure mass makes up for a lot of other weaknesses

 

[ABN_CBT_ENGR]

The reason for the high price is curved vane rotors are more expensive to produce than straight vanes.

Respectfully I would have to see strict proof of that. In terms of machining or casting or finishing the setup and operation time would be virtually identical.

Not saying there isn't a reason but I cant see production costs being one. ( regardless of what point a marketing brochure might try to sell)

 

[TiGeo]

You can get your brakes red hot on the street no problem.

Red hot brakes on the family SUV are a rarity - I stand by what I've been saying, running quality drilled and/or slotted rotors on a daily driven street vehicle is perfectly safe.

 

[Jetronic]

None of that was true for me.

It was true for me, but it might just be the combination with the padsI used performed as it did. EBC drilled and slotted (front and back) and Sparco T-51 pads. Whirring noise, and I could feel the whirring in the brake pedal. Also, and this definitely is a pad issue, not even half the normal brake force first application in the morning. After a long drive without applying brakes the efficiency also was less but not the same as in the morning so maybe there was also a corrosion layer at play. Crazy disc wear aswell, wore faster than the pads...

On the other side, with the OEM pads and discs I could stop hard 4 times in close succession but the fifth time was like someone shoved a block of wood behind the brake pedal. Never had that again with the new brakes.

Current car runs plain discs, with Ferodo DS2500 rear ( can squeal a bit when not cold or not totally up to temp, ie on the street) and Brembo HP2000 up front (dead quiet all the time)

 

[edyvw]

The reason for the high price is curved vane rotors are more expensive to produce than straight vanes. Even the aftermarket Zimmermans are not in the $100 range, they do cost less than the BMW packaged part.

The made in China Stoptechs costs more than the BMW packaged part.

BMW F10 M5 S63 4.4L Brake Rotors - ECS Tuning

www.ecstuning.com

BMW Brake Rotors & Discs for BMW 5 Series F10 (2011-2016) | Turner Motorsport

Shop our wide selection of BMW Brake Rotors & Discs for your BMW 5 Series F10 (2011-2016)

www.turnermotorsport.com

I do not buy cost fo drilling.
Price probably depends on overall brake package (calipers, pads). Interestingly, Zimmerman does make for M5 directional vanes. I guess, when they want they can do it.

 

[UG_Passat]

I do not buy cost fo drilling.
Price probably depends on overall brake package (calipers, pads). Interestingly, Zimmerman does make for M5 directional vanes. I guess, when they want they can do it.

Extra time in the CNC machine for drilling costa more money. Don't you know anything about manufacturing and QC and lean methodology?

 

[edyvw]

Extra time in the CNC machine for drilling costa more money. Don't you know anything about manufacturing and QC and lean methodology?

That will not run price at that level.
But, everything for jealous neighbors.