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Cross Drilled v.s. slotted rotors or both.

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Old 01-30-2006, 07:08 AM
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Default Cross Drilled v.s. slotted rotors or both.

What is the main difference between the three different types of rotors? What are their main uses? Why would I need one over the other?Why would I need any of these over stock vented rotors? What are some pros and cons of using these types of rotors? Discuss.
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Old 01-30-2006, 07:27 AM
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Default Re: Cross Drilled v.s. slotted rotors or both.

Cross-drilled/slotted are for looks only. Most CD/S rotors you see are actually physically drilled, if you plan to do any real hard braking such as in a track event they will crack much faster than a normal blank disc.

Slots are no longer needed because modern pad compounds do no "gas out" like older ones do... the slots gave the gas somewhere to go so the pad could maintain better contact with the rotor.

Cars like Porsche and Ferrari have rotors where the holes are actually cast into the rotor during creation, not drilled, thus they are marginally better.

When I track my car I run blank rotors from NAPA...
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Old 01-30-2006, 08:42 AM
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Default Re: Cross Drilled v.s. slotted rotors or both.

i've never used drilled rotors, but (with all due respect) i'd have to disagree with the previous post regarding slotted rotors. they are noticeably better. besides allowing for out-gassing, they do scrape a little bit of the pads off with every pass under pressure. keeps them from glazing over.

this may have something to do with brake design, too. if they were overdesigned in the first place, may be the benefits of slotted rotors might not make much difference. for a 2200 lb civic with tiny factory brakes - different story.
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Old 01-30-2006, 10:19 AM
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Default Re: Cross Drilled v.s. slotted rotors or both.

Okay, Assuming....Us the viewers no nothing about brakes.What is brake glazing? Why is brake glazing bad or not optimal for performance. Why would you want the rotor to scrape a little bit of the pad off after every pass.
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Old 01-30-2006, 11:48 AM
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Default Re: Cross Drilled v.s. slotted rotors or both.

Drilled rotors are weaker by design.. you removed material after the molding process. Add heat and friction with a quick cool-down time and you have warping.

I don't see much of a problem with slotted rotors.. but again, an un-even surface with less material.

Personal opinion: Big enough rotors (surface area) + good pads + good calipers (compression strength and uniformity) = nice braking.
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Old 01-30-2006, 11:51 AM
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Default Re: Cross Drilled v.s. slotted rotors or both.

I beleive that brake fade is caused by the pad glazing (overheating and causing the pad surface to be ultra smooth).
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Old 01-30-2006, 06:14 PM
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Default Re: Cross Drilled v.s. slotted rotors or both.

Actually, slotted rotors dissipate heat faster. Glazing is caused by trapped heat in hard breaking. Rotors can sometimes warp just because of this.

The slots allow a push of the gasses and heat out and away from the rotor surface. This is why they are channeled.
The drilled holes are for the same thing basically. They allow heat to leave the suface much faster during hard braking.
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Old 01-30-2006, 06:21 PM
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Default Re: Cross Drilled v.s. slotted rotors or both.

i pefer sloted rotors
i dont know much, bet they seem to help with fade alot
i have noticed that the rolex 24hr cars all use slotted
all those millions in recearch must mean something :shrug:
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Old 01-30-2006, 06:23 PM
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Default Re: Cross Drilled v.s. slotted rotors or both.

Originally Posted by Cobra4B
Cross-drilled/slotted are for looks only. Most CD/S rotors you see are actually physically drilled, if you plan to do any real hard braking such as in a track event they will crack much faster than a normal blank disc.

Slots are no longer needed because modern pad compounds do no "gas out" like older ones do... the slots gave the gas somewhere to go so the pad could maintain better contact with the rotor.

Cars like Porsche and Ferrari have rotors where the holes are actually cast into the rotor during creation, not drilled, thus they are marginally better.

When I track my car I run blank rotors from NAPA...

he is speaking the truth. Look at professional race orginazations, like NASCAR, JGTC, or F1...no one is running cross-drilled, nor slotted rotors...simply for show. The were used when brake pad materials were poor and limited in quality
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Old 01-30-2006, 06:32 PM
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Default Re: Cross Drilled v.s. slotted rotors or both.

Originally Posted by gsxtcy
he is speaking the truth. Look at professional race orginazations, like NASCAR, JGTC, or F1...no one is running cross-drilled, nor slotted rotors...simply for show. The were used when brake pad materials were poor and limited in quality
no, they are running carbon/ceramic discs






fail

now turn on speedvision and look at rotors on the scca cars, open a magizene and look at the time attack cars
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