Are cross drilled rotors worth it...? - BMW Forum

Charleston Chu · 10-10-2005, 01:50 AM

I have the opportunity to buy cross drilled and slotted rotors really cheap from my LCPS (local car parts store) and want to know if it is actually worth it. Or should i just buy the REALLY cheap regular ones? I have heard that you need street compund pads to use the "better" rotors.

Chuck

325eXTATIC · 10-10-2005, 12:11 PM

Hi Charleston! Great user name!
Be careful when purchasing slotted and cross drilled rotors. They DO serve a purpose on faster or heavier high performance cars, or those driven extensively at the limit. Slotting a rotor can create significant weak points if not done properly. Pay attention to see if the slots extend all the way to the outside edge of the rotor. If it does go all the way to the end, I would recommend avoiding the rotors. If they stop before the outside edge of the rotor, you have a better chance of having the rotors last longer. The main reason for X-drilling and slotting is to allow for the gasses created by high speed braking to excape and keep the pad seated on the rotor without floating on those gasses. 90% of the time, street use will never generate the conditions that make these features necessary. That being said, I put them on my old air cooled VW Beetle, and they looked BAD ASS! So, if you can live with a shorter expected life for the rotor, and you get a well machined/slotted/drilled rotor, I say GO FOR IT!

Hope this helps!

Josh W.

Charleston Chu · 10-10-2005, 04:41 PM

Thanks... I'll keeo that in mind... Pads and Rotors for F&R are like $240US... I figure that it's not a bad deal... But I can get the regular cheap ones for $200CAN. I figured that the extra $75 or eight dollars might be worth it... but then again... maybe not based on the little enhancement that daily driving puts on them... I agree that they look cool but may not be reasonable. I raced that the AutoX in Calgary this summer and I didn't find the braking capability to be any worse then the fact it is an automatic Tranny!

Preston Smith
aka Charleston Chu
(chinese guy... english name... more people believe that Charleston Chu IS my REAL name!)

325eXTATIC · 10-10-2005, 04:55 PM

Are you a twinkie? Sorry, my roommate is the whitest asian guy I have ever met, and People call him a twinkie (White on the inside, yellow on the outside) and he gets such a kick out of it. He proudly proclaims that status! LOL

No offense, just thought you might get a kick out of it like my roomie!

Josh W.

DJProfessor · 10-10-2005, 05:24 PM

actually everyone slaps on cross drilled this, and slotted that and misses the boat entirely.........the purpose of those rotors is to help disappate (sp) the heat that braking causes.......well if you want to get rid of the heat you use cool air right? well the best bang for the buck mod for braking is to put some duck works that draws cold air from the front and directs it onto your calipers.....that mod will help braking considerably. that was the first thing we use to do on the old track Porsche's to help them with braking.

Bmw1990 · 10-10-2005, 09:48 PM

Basics physics states that the more surface area you have the easier it is to disapate(?) heat. Putting holes in the rotor only weakens the rotor and can cause cracks. Now in the correct application these rotors can be very useful, but everyday guys like us, who might only race on the on and off ramps they are a waste of money. Get some nice pads and some nice rotors. And like DJProfessor said, the more air you can get in there the better.

Charleston Chu · 10-11-2005, 12:45 AM

Quote:

Originally Posted by 325eXTATIC

Are you a twinkie? Sorry, my roommate is the whitest asian guy I have ever met, and People call him a twinkie (White on the inside, yellow on the outside) and he gets such a kick out of it. He proudly proclaims that status! LOL

No offense, just thought you might get a kick out of it like my roomie!

Josh W.

That is hilarious.. I'm definitely using that one... I was adopted by a chinese lady (mom) and a british guy (dad). I look 100% chinese... Because I am but I have the second whitest name ever... only second to John Smith... and that's my dad's name...! Thanks for the great laugh!

Preston

Kowalski · 10-11-2005, 09:15 PM

Quote:

Originally Posted by Charleston Chu

That is hilarious.. I'm definitely using that one... I was adopted by a chinese lady (mom) and a british guy (dad). I look 100% chinese... Because I am but I have the second whitest name ever... only second to John Smith... and that's my dad's name...! Thanks for the great laugh!

Preston

hahaha
thats awsome

filter27e · 10-12-2005, 09:19 PM

Lol reminds me of this guy I used to work with. He was Korean I think, and on his name badge it had his Korean name which was something that start with "Ch" and was like 10 letters long, then it had Jeff. So his name badge read like "Che-somethingasian / Jeff" Cracked me up first time I saw it.

Anyways yeah, brakes. Guy who said that it was to stop your pads from floating on gasses was halfway right. Problem is modern pad material doesn't release gasses when it gets hot. I think I heard somewhere that there was a genuine perk to having slotted/drilled rotors, but it wasn't a big enough deal for me to remember. It's all looks, until they break because somebody charged you $100 to drill some holes in cheap rotors and didn't tell you. If you get them, pay the $ and get them from a good source.

BMW Lover · 10-12-2005, 10:57 PM

i upgraded my brakes like 6months ago and i sometimes drift my car and push it to its limits...here and there :-P and well i have ate power disks in the front, oem disks in the rear, and bmw cermic pads all around...it made a phenominal difference in how i take corners and such...just an fyi ^_^

filter27e · 10-14-2005, 11:03 PM

Quote:

Originally Posted by BMW Lover

i upgraded my brakes like 6months ago and i sometimes drift my car and push it to its limits...here and there :-P and well i have ate power disks in the front, oem disks in the rear, and bmw cermic pads all around...it made a phenominal difference in how i take corners and such...just an fyi ^_^

And from his sig... "Member of the "I'm 18 and Own a Bimmer" Club"

Oh dear god at least I don't ever drive near cali lol

Sorry dude just had to pic on you... we all wrecked a car or two when we were 18

Just keep it to a road by yourself so you can run into a ditch at 45 like I did and only hurt your wallet