Em Bee Lover

2007 4Matic, non-sport. Need to replace rotors and pads. Std. MB rotors are "blank", I found. Current ones (second set, I'd guess--74000 miles) are drilled.

What value is there and/or is it worth it to go to drilled? Slotted? Drilled and slotted.

Or, for plain ol' driving are oem blanks just fine?

Lastly, all I need are pads, rotors and two wear sensors, correct?

Thanks.

Chris The Swede

I did drilled on mine.Think it loks SO mUCH better and matches the front look better.



Finnished result.

marthyh

True ..optical-wise its nice to have holes in your disks..
Brake-surface wise I would tend to stick to plain ..

Unless your planning on a disk-diameter/caliper upgrade to have the same sq.inch surface, which would imply larger wheels and tires to fit as well; if you do not already have that ..

Quadcammer

essentially zero benefit to drilled and slotted rotors in terms of performance and you risk some cracking on the drilled ones.

mistertonyn

I thought they were suppose to release the gas or heat better through the holes when the brakes are applied.

Chris The Swede

Of course they do..Why would you even invent them otherwise.

boost420

In the old days, the brake pad material did have gas build up that could float the pads against the rotor, nowadays, the pad material does not have that same gas build up, so drilled rotors are purely cosmetic and do run the risk of cracking because the holes are now a weakness in the metal. Slotted rotors do have some performance gain, but at the expense of pad life. Unless you are tracking your car, blanks are perfectly fine and will hold up to almost anything that you throw at them for street use.

mistertonyn

You mean to tell me AMG put the drilled rotors on just for cosmetic reasons??
Kinda hard to swallow that one.....

Chris The Swede

Exactly....

marthyh

Boost 420 is right about the 'gassification of solids' etc. bc of new materials, slotted still used to keep the surface clean etc.
But mistertonyn and Chris the Swede ,have point as well: a lot of different car-manufacturers like ,Porsche ,Ferrari etc. make holes in their disks as well..
Except, when there is serious racing going on; Nascar/F1 they would prefer to have Surface rather then holes..
I guess as usual, the engineering truth ,is a solution with compromises and for performance-street cars that might as well be slotted/drilled and it is not so bad marketing wise to have the optical aspect as well.

Quadcammer

sure. AMG does all kinds of thinks for cosmetic reasons. That AMG bodykit ain't likely doing much for downforce.

It was at some point ingrained in sports/high end luxury buyers that the brakes on high performance or high end cars should have holes or slots.

May there be a modicum of benefit if you are doing 30 minute sessions on a road course and really getting a ton of heat into the brakes? possibly.

For even semi-crazy street driving..no difference.

I'll say this: If you are driving hard enough to notice a difference from slotted/drilled rotors, you'll have boiled the brake fluid a while ago.

boost420

That is exactly what I am telling you. Here's some info, there are countless articles exactly like this.

http://www.marcusfitzhugh.com/CLK/DIY/brakecdrill.html

Additionally, here is the rotor off of the SLR, notice any cross drilling there



Surface area dissapates heat, vane design and airflow to the rotor are far more important then some little holes that actually take away from the overall surface.

mistertonyn

oh man...hope dealers are not way overcharging them over the regular discs.

malahhaor

Although many arguments seem compelling, until someone runs two rotors made from same material, agains each other measuring braking ability and heat extraction , I'm going to take arguments one way or the other with a grain of salt.
Just going to stay with what's on the car and not spend money going one way or another.

One thought comes to mind is that Benz prides it self on safety and if my front rotors being drilled are less effective I would think they would stay with solid disks.

boost420

If you want to continue putting crossed drilled rotors on your car because you think that it adds some type of additional safety, i have some beach front property you might be interested in. I run them on my amg, but i do not have a false illusion that they add anything other than a look that i like.

malahhaor

You want to tell me that you actualy went out of your way and got all solid disks on your S55?
Keep your smart alek comments to your self along with your property jack

boost420

Reading comprehension pawns you, Richard, but that doesnt suprise me considering you have added so much insight to this post.

Quadcammer

Once again, with even very aggressive street driving, there is no perceivable difference here.

the brakes are fine, drilled or not.

ima55r2

The SLR has carbon ceramic rotors so drilling or slots don't apply.