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Brake rotors, drilled or not?

  1. Oct 10, 2010 #1
    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.
  2. jcsd
  3. Oct 10, 2010 #2
    That depends whether the "drilled" rotors were cast like that, or were just OEM blanks and then drilled :eek:
  4. Oct 10, 2010 #3


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    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.
  5. Oct 10, 2010 #4
    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 becuase 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.
  6. Oct 10, 2010 #5
    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.
  7. Oct 11, 2010 #6

    Ranger Mike

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    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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  8. Oct 11, 2010 #7


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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.
  9. Oct 11, 2010 #8
    I can speak only to their use on motorcycles, but drilled rotors improve wet braking performance.
  10. Oct 17, 2010 #9
    What about slotted rotors? Yea or nay.
  11. Oct 17, 2010 #10


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    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.
  12. Oct 19, 2010 #11


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    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.
  13. Oct 20, 2010 #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 thats a different story. I suspect the OP realises 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 isnt 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.
  14. Oct 25, 2010 #13
    not sure
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