Are drilled rotors better for brake cooling?

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Discussion Overview

The discussion revolves around the effectiveness and safety of drilled and slotted brake rotors, particularly in the context of automotive applications. Participants explore the implications of using drilled rotors for cooling, potential weaknesses, and the suitability of different rotor types for various driving conditions.

Discussion Character

  • Debate/contested
  • Technical explanation
  • Exploratory

Main Points Raised

  • Some participants suggest that drilled rotors may help keep brakes cooler under heavy load, while others argue that they weaken the rotor and reduce effective surface area, leading to decreased braking power and increased wear.
  • A participant notes that drilled rotors are not necessarily more likely to fail than non-drilled rotors, but cautions that they may not provide better braking performance for typical road use.
  • Concerns are raised about the safety of drilling rotors, with one participant emphasizing the importance of using properly designed rotors rather than modifying OEM blanks.
  • Some participants advocate for slotted rotors, citing improved wet weather braking performance, while others caution against DIY modifications unless one has sufficient knowledge and experience.
  • There is a suggestion that upgrading brake components may be unnecessary for general road driving, as standard brakes are typically adequate for locking wheels without fading issues.
  • One participant raises the question of the intended use (road driving vs. track days or racing), indicating that this could influence the appropriateness of drilled or slotted rotors.

Areas of Agreement / Disagreement

Participants express a range of opinions on the use of drilled and slotted rotors, with no clear consensus on their effectiveness or safety. Some advocate for their use in specific contexts, while others strongly advise against them for general automotive applications.

Contextual Notes

Participants highlight various assumptions about rotor design, material suitability, and the impact of driving conditions on brake performance. The discussion reflects differing levels of expertise among participants regarding brake modifications.

kgbgru
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Hello all,.
I have been doing work on my brakes and now I would like to get new brake rotors. I replaced the standard brake pads with performance pads; I love them, and now I want even more. I already am going to replace the tires but I can't decide what brake pads I want.
I have read that drilled rotors help keep the brakes cooler but I have also read that they weaken the rotor, since you are drilling holes in them. Can anyone give me a yea or nay on slotted rotors. I just don't know enough to make a reasonable estimate.
 
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That depends whether the "drilled" rotors were cast like that, or were just OEM blanks and then drilled :o
 
Either don't bother, buy proper ones, or know absolutely what you're doing. The thought of a disc failing under use fills me with dread. And as my dad says, brakes are only one of the things that can stop you.
 
Brake discs that are designed with drilled holes are no more likely to fail than any other drake disc. (Well they are but will be like 99.9% as reliable under road use)

However don't expect better braking because you have drilled discs. If you are using them for the road you are wasting your money as discs won't get hot enough to fade.

Either go for bigger dics, or a bigger caliper.
 
Drilling holes in the rotor is a trade off. The advantage is that it keeps the rotor cooler under heavy load. The disadvantage is that there is less effective surface area and braking power is reduced and the rate of wear is increased. As noted above, if you're using your car for general transportation than there is absolutely no reason to get drilled rotors unless you want some kind of "cool" factor.
 
no one ,,repeat ..NO ONE runs drilled rotors any more..they are ok on a go cart but forget it on a car. the thinking was that it helped cooling and in the old days it may have. not with new technology, now rotor manufacturers mill in vents to remove the gas build up on the pad/rotor surface.
drilled rotors will warp much easier than non drilled rotors and will crack easier than non drilled. save your money and if you want to improve your disc brake performance, add some cooling ducts, to the front where all the weight is.
 

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Drilled rotors are probably advisable for the front brakes of motorcycles, because they do the bulk of the braking and you don't want fade in that application, especially in heavy bikes. Automotive brakes are already designed well for their intended use, and shouldn't be tinkered with.
 
I can speak only to their use on motorcycles, but drilled rotors improve wet braking performance.
 
What about slotted rotors? Yea or nay.
 
  • #10
Yes, but please don't do it yourself unless you know what you're doing! I use slotted rotors on my Seven and the wet weather braking performance seems loads better than before.
 
  • #11
I always understood that the drilled / slotted brake discs were of a different (and suitable) material.
If your knowledge of materials is appropriate then you will know whether it is appropriate to drill them. If not, don't - on pain of death, perhaps.
 
  • #12
This is a similar thing to "if you have to ask the price, you can't afford it".

If you are asking about drilled discs you don't have the experience to drill them yourself. However if you are asking about buying drilled/vented/slotted discs that's a different story. I suspect the OP realizes taking a drill to a disc is a bad idea and that he was going to buy new.

To be honest upgrading pads/discs/calipers is all pointless for stopping faster on the road unless you buy much better tyres. As standard brakes are enough to lock the wheels and fade isn't an issue.

One thing that needs to be asked that hasn't been is: Why are you doing this? Is it just for road driving, or track days, or races? The responce to this question will likely change the answers we give.
 
  • #13
not sure
 

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