ngl1145

I was looking at my brake rotors this morning and noticed that the rotors do not seem directional. So if I look at the right side of the car, the way the cross drill pattern is made looks like it's going in the ///// direction. If I look on the left side of the car, the patern goes \\\\\. Just thought that was interesting. I would have thought that the direction of the holes would go in a similar direction.

Joe Z

iTrader: (10)

You I just noticed you are right...!!!

They only made them front & rear specific and not left & right specific...

I wonder why they did that??

They did decide to make 4 different wheels / part numbers since they are directional designs..

I wonder if they missed this or just not a technical issue which would warrant 4 different part numbers..

I agree that they should visually be all pointed in the same unifrom direction...
Drivers Side ///// & Passenger Side \\\\\


Here are a few various Blue IS-F's that show them pointing all one way. In the non-uniform direction.

Nice pics to the owners... of course...

Drivers side F & R /////


Passenger Side R /////


Passenger Side F /////


Joe Z

rominl

iTrader: (4)

umm interesting, that's pretty "awkward" setup. all the bbk i have owned, the rotors are all directional

Joe Z

iTrader: (10)

Agreed

Even when i bought aftermarket cross drilled & slotted rotors for my IS300, they were directional as well...

Joe Z

kt22cliff

Although asthetically speaking it's probably better to have the "holes" lined up in the same way directionally, what makes the rotors "directional" is NOT where the holes are or how they are oriented. It's the directional design of internal vanes that makes the rotors "directional".

rominl

iTrader: (4)

right, but then if the internal vanes design are directional, then the drilled holes should be in the same direction too no?

Robs IS250

iTrader: (4)

YEA WHEN I LOOKED UP THE bbk FOR PRICING SO I CAN PUT IT ON MY CAR, BOTH FRONT DISCS WERE THE SAME PART NUMBERS..

gshb

haha you guys are funny. you should check out the stock wheels that come on the 996 carrera. the spokes are contoured and curved to point one direction, but they didnt make the left/right side match to the same direction!

Joe Z

iTrader: (10)

Totally NOT surprised considering we can clearly see that they only designed different fronts & rears and NOT lefts & rights...

Joe Z

iTrader: (10)

If your theory is right... then one side of the IS-F Brakes/Rotors are not going to cool correctly since again, the holes are drilled into the those "vanes"..

Next time I can, I will look directly inside the IS-F Rotors... on both sides..

Joe Z

rominl

iTrader: (4)

that's what i have asked as well. with them having the same part number, does that mean the vanes are not directional at all? meaning they just go straight to the center? doesn't make sense right? and if they are directional, that means the vanes flow differently left and right? and if so, does that mean they discover the "direction" doesn't really affect cooling?

kt22cliff

I do think it's kind stupid to not have holes line up relative to the rotational direction. If anything, just to not confuse people when mounting the rotors or when you need to swap out the friction rings. However, my point is the way vanes are designed is what makes these rotors directional not how the holes happen to line up directionally. Since these holes are not doing really anything but serve aesthetic purpose with modern brake pads - i.e. there is not really outgassing problem anymore with modern brake pads - you could have for example one hole per in between vane spaces. In that case you wouldn't see any directional pattern with "holes" and rotor will still need to be lined up correct vane rotation-wise. But it is puzzling why the hole patterns are not lining up left side vs right side of the car IF they are drilled in between same vanes as to represent the shape vanes are curved. At least on performance friction rotors I've dealt with - dimpled not drilled but the dimples do line up this way;

rotation <- ///

and if I'm not mistaken, stoptech's and brembo's are same way also. So if that's the case then the passenger side would the one mounted "wrong" way

rominl

iTrader: (4)

/// or \\\ with direction can be dependent on design.

i can't remember exactly now, but i think ap racing has things in certain direction and brembo has it in another direction. i am sure they do a lot of research

Joe Z

iTrader: (10)

So I was just checking out a Brand New M5 parked next to me at work,
and both Drivers & Passenger side rotors are pointing correctly...

Like So....

I have added a second pic below this ONE, which HAS BEEN MIRRORED BY ME.
To show how they are on a new M5 and many other models or aftermarket rotors

Drivers Side


Drivers Side (Mirrored)


And yes I realize the "F" is backwards and the sterring wheel too..

Joe Z