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cross drilled vs. dimpled

19K views 13 replies 11 participants last post by  ChargerPursuit  
#1 ·
looking to buy new rotors and wanted to know the difference between cross drilled and dimpled? which one is better? difference between them?
 
#2 ·
Race on the track, like road course sort of track? Or routinely brake so hard your brakes smell funny? If not, there's no real functional difference, except the drilled ones will most likely wear out your pads a bit faster.
 
#3 ·
Dimpled, like slotted rotors, will keep the pads clean but will not be compromised like a drilled rotor will be.

I have had many customers that have bought drilled rotors over the years, and every one have over time cracked and pieces of the rotor have come off....sometimes causing major problems.....through fenders and firewalls under extreme speeds. This is if they are cast iron like most rotors are. If they are made of billet steel like Wilwood that is a different thing. They have shown to be very good but extremely expensive etc.

This has not happened to dimpled and slotted rotors as they are not compromised by the drilling. For most street applications, the dimpled would be a better fit for your car!:bigthumb:

Regards,
Brian
BND Automotive LLC:driving:
440-821-9040
www.bndautomotive.com
 
#14 ·
Dimpled, like slotted rotors, will keep the pads clean but will not be compromised like a drilled rotor will be.

I have had many customers that have bought drilled rotors over the years, and every one have over time cracked and pieces of the rotor have come off....sometimes causing major problems.....through fenders and firewalls under extreme speeds. This is if they are cast iron like most rotors are. If they are made of billet steel like Wilwood that is a different thing. They have shown to be very good but extremely expensive etc.

This has not happened to dimpled and slotted rotors as they are not compromised by the drilling. For most street applications, the dimpled would be a better fit for your car!:bigthumb:

Regards,
Brian
BND Automotive LLC:driving:
440-821-9040
www.bndautomotive.com
I have Power Stop drilled and slotted rotors on my older Pursuit. After the fact, I wish I had only gotten slotted because of what Brian mentioned. It is weakening the rotor to some extent and I am not hard on brakes. The slotted should be enough to release some gases and look cool too.
 
#4 ·
Obviously a dimple is only a surface divot. The holes go clear through the material and perforate the inner air channel or vent.

A dimple will look the part of the hole without sacrificing the life of the part common to drilled rotors.

The holes allow air passing through the rotor wall or cheek to aid in pad cooling and out gassing. The effectiveness of that today is debatable. The problem becomes thermal expansion and contraction which is compromised when you have this hole. In time the holes develop stress risers around their perimeter and grow as the rotor is heat cycles over and over until they eventually become larger and a potential safety issue.

While some suppliers tout the holes as having a radius to prevent this the reality is that the radius is only on two of the four surfaces. Even with the radius the expansion problems remain anyhow. Not a bad thing; just not some magic either.

The dimple simply give the buyer the 'look' of the drilled rotor without the compromise of integrity. Not a bad idea. Not as effective perhaps as a slotted rotor in aiding pad venting however they do give a zoomy look to an otherwise plain finish that should provide years of trouble free use not found in many drilled rotors.

For the street either are suitable due to the lower temps in daily use. For the track use the life of the drilled rotor will be quite short if run with a good pad for 30min open sessions and you'd probably be better off with a plain or slotted finish. None of these however truly increase "stopping power" they only aid in pad venting and cleaning.
 
#5 ·
hey bro i would stick with oem or part store stuff!

i currently have dimpled/slotted rotors frm brakeperformance im not sure if its the free pads or the rotors but braking sucks i literally glide to a stop sorta like those fighter jets that land on those ships and squeaks like hell.

before that purchase i had oem rotors n autozone pads believe they was duralast gold or something and they were great.
 
#6 ·
Have to ask,...

...but did you bed them properly? Had dimpled and slotted rotors from R1 on my 06 R/T, she would sling you through the windshield stopping. No glide at all, immediate grip and slow.
 
#7 ·
Thanks Banco, I was planning on buying thosse you have now. I have slotted and dimpled already from another company. I folled the break in process but after a month they were squeeling and after a yr with them they are squeeling pretty loud. I think I will go with OEM style.
 
#9 ·
No prob Bro before i change the rotors out im gonna get those pads i was talking about first frm autozone again.. it's raining here in GA and i damn near glided from one stop light to another
 
#10 ·
Just to be clear, slotted, dimpled or cross-drilled rotors do NOT increase stopping power. The are designed to reduce brake fade.

Brake fade happens when gasses build up under the pad in heavy braking and cause the pad to glide on the rotor surface like the puck in an air hockey game. The dimples, slots or drilled holes allow the gasses to escape and let the pad maintain positive contact with the rotor. This also enhances cooling of the rotor which builds from the hot gasses.

But be careful with this on regular non-racing applications since racing pads and rotors don't perform well until they are very hot under racing conditions. Using racing brakes on normal applications will result in sub-optimal braking performance often described as being very weak.
 
#11 ·
I'm using Powerstop cross drilled and slotted rotors with EBC Red Stuff pads and the difference in performance is night and day. The bastards at the dodge dealership did a tire rotation and over-torqued the **** out of my stock rotors (i.e. impact gun, NOT a torque wrench!) and caused serious rotor warping. I haven't even fully been through the pad's "bedding in" surface and let me tell you, I can throw the anchor out. I had my friends strangling on their seatbelts. Cracking may very well be an issue at some point, but I'm not going to be doing any extensive auto cross or track runs so the amount of stress on the brakes is kept to a minimum 95% of the time.