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Old 05-21-2018, 05:50 PM   #1
blue05wrx_
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Default DBA T Slot Rotors

Are they worth the money? Saw them on rallysportdirect and i'm thinking about buying both front and back for my wrx. If they are worth it, should i also spend the extra cash and get new pads and brake lines?
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Old 05-21-2018, 06:30 PM   #2
fleezy
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You will see faster bite and cooling, but you will see more wear and potentially uneven wear with this type of slotting. personally i prefer drilled+slotted.

unless you need the extra bite, and your are frequently decelerating very quickly (ie. have a good amount of track time), i wouldn't fork out $300 for these + tax + shipping....
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Old 05-21-2018, 11:29 PM   #3
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Quote:
Originally Posted by fleezy View Post
You will see faster bite and cooling, but you will see more wear and potentially uneven wear with this type of slotting. personally i prefer drilled+slotted.
Drilled? Really? Where's your source on any of the above?

DBA rotors are quality parts, though I would recommend the 5000-series whenever you can due to the replaceable rotor rings.

I noticed no increased bite on the 4000 or 5000-series rotors nor did I see additional/uneven pad wear and I've been running them for years.
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Old 05-22-2018, 02:58 AM   #4
blue05wrx_
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Quote:
Originally Posted by fleezy View Post
You will see faster bite and cooling, but you will see more wear and potentially uneven wear with this type of slotting. personally i prefer drilled+slotted.

unless you need the extra bite, and your are frequently decelerating very quickly (ie. have a good amount of track time), i wouldn't fork out $300 for these + tax + shipping....
I saw the Stoptech drilled and slotted rotors and the stainless steel brakelines as well. Are they just as good as the DBA rotors?
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Old 05-22-2018, 02:58 AM   #5
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Originally Posted by mrsaturn7085 View Post
Drilled? Really? Where's your source on any of the above?

DBA rotors are quality parts, though I would recommend the 5000-series whenever you can due to the replaceable rotor rings.

I noticed no increased bite on the 4000 or 5000-series rotors nor did I see additional/uneven pad wear and I've been running them for years.
What's bad about drilled rotors?
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Old 05-22-2018, 03:58 AM   #6
mitch808
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Are there better ways to spend your money? Sure. But those are good, very good OE sized rotors.

For a lot less, centric makes very good OE sized rotors too.

It all depends on your goals.
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Old 05-22-2018, 09:16 AM   #7
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Quote:
Originally Posted by blue05wrx_ View Post
What's bad about drilled rotors?
Under high stress and/or temp, drilled has a tendency to crack. I was able to crack a set of DBAs in 2 sessions on a track day. Learned the hard way...
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Old 05-22-2018, 12:47 PM   #8
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This is a fairly divisive opinion, but the minor benefits of drilled rotors are not worth the added wear and tear on the pads, and the tendency to crack. I'm not talking about surface cracks after a track day - those aren't a problem.
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Old 05-22-2018, 02:04 PM   #9
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I believe JOF is not referring to surface cracks, but serious cracks in the rotors centered in the drilled holes in the rotor.

I've seen some pretty bad cracked rotors before where the rotors cracked at the drilled holes themselves.

Allegedly, the drilled holes are for cooling. Even if that were true, and they had added value, I would not use drilled rotors myself due to the cracking issue.
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Old 05-22-2018, 03:08 PM   #10
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Holes do basically nothing for cooling. What they do is keep the pad to rotor interface clean and clear of dust/water/pad material/gasses, improve bite, and reduce weight.

Slots however give you most of the benefits of the holes without creating spots for cracks to form.

On a street car, you are probably never going to have issues with cracking, and if you want drilled rotors to look cool that's fine. Go right ahead- it's your money. You aren't going to notice a difference except for sound when braking hard.
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Old 05-22-2018, 05:09 PM   #11
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The way I've always understood the goal of the holes vs. slots is that slots were for clearing dust while holes were intended to give a cheese grater effect in adding bite to the pads. I've used drilled rotors long ago and not once did I notice any added bite. On motorcycle brakes, holes are mostly there to just make the rotor lighter.

Once you get into serious motorsport components, you'll notice all the big names (AP, Alcon, Brembo) use a J- or C-shaped groove to basically give the added bite AND dust cleaning all in one without turning the rotors into Swiss cheese.

All of the effective cooling is controlled by the vane design - one needs to look no further than a centrifugal fan to understand this.

The holes may have a different purpose in carbon rotors, I don't have much experience with these beyond some Porsche OEM parts. Most motorsport carbon rotors I've seen are blanks.
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Old 05-22-2018, 05:51 PM   #12
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So i decided that i won't be getting the DBA rotors. If i did, i wouldn't have enough for pads and lines lol. Are there any good alternatives to those rotors? Slotted rotors seem to be favored over drilled.

Edit: Are the Stoptech drilled and slotted rotors good for daily driving and taking up to the canyons on weekends?
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Old 05-22-2018, 07:39 PM   #13
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Quote:
Originally Posted by blue05wrx_ View Post
So i decided that i won't be getting the DBA rotors. If i did, i wouldn't have enough for pads and lines lol. Are there any good alternatives to those rotors? Slotted rotors seem to be favored over drilled.

Edit: Are the Stoptech drilled and slotted rotors good for daily driving and taking up to the canyons on weekends?
They'll be fine, just don't expect any appreciable performance benefit over plain blank rotors.
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Old 05-23-2018, 12:48 AM   #14
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Quote:
Originally Posted by jamal View Post
Holes do basically nothing for cooling. What they do is keep the pad to rotor interface clean and clear of dust/water/pad material/gasses, improve bite, and reduce weight.

Slots however give you most of the benefits of the holes without creating spots for cracks to form.

On a street car, you are probably never going to have issues with cracking, and if you want drilled rotors to look cool that's fine. Go right ahead- it's your money. You aren't going to notice a difference except for sound when braking hard.
jamal's got it.
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Old 05-23-2018, 07:04 AM   #15
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Quote:
Originally Posted by blue05wrx_ View Post
So i decided that i won't be getting the DBA rotors. If i did, i wouldn't have enough for pads and lines lol. Are there any good alternatives to those rotors? Slotted rotors seem to be favored over drilled.

Edit: Are the Stoptech drilled and slotted rotors good for daily driving and taking up to the canyons on weekends?
KNS Brakes. Less expensive options made by DBA with KNS branding.

I guess you missed the point everyone has been making about drilled rotors. Drilled rotors biggest benefit is for looking pretty. Drilled rotors are also prone to cracking. Not surface cracks, but cracking through the rotor face.

Slotted rotors are better. As mrsaturn said, " you'll notice all the big names (AP, Alcon, Brembo) use a J- or C-shaped groove to basically give the added bite AND dust cleaning all in one without turning the rotors into Swiss cheese. ". The - or C- shaped groove would be slotting, as opposed to straight lines.

I also find that the slot helps to remove water between the pads and the rotor face faster than with blank rotors.
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Old 05-23-2018, 03:02 PM   #16
blue05wrx_
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Quote:
Originally Posted by Samurai Jack View Post
KNS Brakes. Less expensive options made by DBA with KNS branding.

I guess you missed the point everyone has been making about drilled rotors. Drilled rotors biggest benefit is for looking pretty. Drilled rotors are also prone to cracking. Not surface cracks, but cracking through the rotor face.

Slotted rotors are better. As mrsaturn said, " you'll notice all the big names (AP, Alcon, Brembo) use a J- or C-shaped groove to basically give the added bite AND dust cleaning all in one without turning the rotors into Swiss cheese. ". The - or C- shaped groove would be slotting, as opposed to straight lines.

I also find that the slot helps to remove water between the pads and the rotor face faster than with blank rotors.
Found these.

https://www.knsbrakes.com/c/car-seri...eet+Brake+Pads
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Old 05-23-2018, 03:36 PM   #17
Jawsofire
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Quote:
Originally Posted by Samurai Jack View Post
I believe JOF is not referring to surface cracks, but serious cracks in the rotors centered in the drilled holes in the rotor.

I've seen some pretty bad cracked rotors before where the rotors cracked at the drilled holes themselves.

Allegedly, the drilled holes are for cooling. Even if that were true, and they had added value, I would not use drilled rotors myself due to the cracking issue.
^Yep. Actually cracks all the way through the rotor from every other drilled hole to the outer diameter. Front and back surface. Rear rotors were fine.
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Old 05-23-2018, 04:50 PM   #18
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The benefit of 5000-series DBA stuff is that it saves your bearings and also has a replaceable ring. If that's out of your budget, I'd stick with OEM (or KNS) blanks for the time being and spend the money on good pads.
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Old 05-24-2018, 05:15 PM   #19
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I'm very happy with my DBA 5000 T-slots. I also considered RacingBrake two-piece rotors, but ultimately decided to go with DBA.
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