Help me pick out the right rotors - much debate on the 18z retrofit rotors...

[LakeTahoeQuattr]

So i am going to pull the trigger on the BBK retrofit for my ar. After much reading, the 18z caliper is for a "350mm" however many people say that we must run a 345mm rotor to make the pads fit better or something to that extent. I also read that people are using a 18z with a 345mm and 17z pads. People say that there is less overhand or something to that extent. Anyone heard of this?

So i was looking at getting the ml55 amg 345 mm rotors until I learned that the vanes are not directional from side to side! They made each rotor the same so one gets efficient cooling and the other one gets no cooling! What the heck is going on here? Why would Mb design their rotors his way?

Does anyone know of a a manufacturer of the ml55 rotors with right and left vane cooling?

It seems that the only choice is a two piece girodisc or JHM to get the correct vane orientation...

[ricekikr]

Iirc DBA is the only cast directional rotor that works correctly for both sides. After that its the $$$ floating rotors

17z pads because it overhangs on the inside.

These are 17z ebc yellow pads on 345mm rotors. There's still a bit of overhang with them, 18z pads would be a lot more.

[gmdiluca]

I think stop tech makes a directional vane rotor for the ML55. Not 100% sure though


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[LakeTahoeQuattr]

Iirc DBA is the only cast directional rotor that works correctly for both sides. After that its the $$$ floating rotors

17z pads because it overhangs on the inside.

These are 17z ebc yellow pads on 345mm rotors. There's still a bit of overhang with them, 18z pads would be a lot more.

So then the ONLY benefit of the 18z vs 17z on a single piece rotor is rotor size. 330 vs 345.

I could not find the ML 55 rotor made by DBA in their catalog.

I thought Ricam tried the stop tech and they were single direction...

[ricekikr]

*** confirm this is the correct one first. Just did a quick google search ***
http://www.lpiracing.com/DBA4552XS-D...078p159166.htm

Another benefit is better piston diamters suited for the b5 master cylinder. And imho looks better. 17z, to me, looks quite odd (huge caliper makes rotors look tiny)

The only negative is maybe rim size. The 18z fits under 17inch rs4 rep barrels but hit the spokes, i imagine the 17z will hit the spokes as well. Same thick calipers.

But since 18z can be found for the same price, sometimes less, than 17z its almost a no brainer unless you prefer smaller wheels.

[LINDW4LL]

So i was looking at getting the ml55 amg 345 mm rotors until I learned that the vanes are not directional from side to side! They made each rotor the same so one gets efficient cooling and the other one gets no cooling! What the heck is going on here? Why would Mb design their rotors his way?

Does anyone know of a a manufacturer of the ml55 rotors with right and left vane cooling?

It seems that the only choice is a two piece girodisc or JHM to get the correct vane orientation...

Audi does the same thing on the R8. Same rotor used on both sides. Most OEMs do it this way, and aftermarkets follow suit since that's "OE-spec". Same thing on most AMGs and many other high end cars. They don't seem to have any problems with brake cooling.

You won't have any issues with the ML55, but by all means go two piece if you don't mind spending the money.