New slotted rotors

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kosteniuks17

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Mazda Protege5 2003
So I purchased a set of four new slotted and drilled rotors from R1 concepts and a set of 4 new calipers that I plan to paint red this weekend. I have my mechanic friend installing it all next week some time. So my question is which way are the slots in the rotors supposed to face. It seems like this was questioned before but no one had a legitimate answer. I just dont want my brakes to be squeaking cause I put them on the wrong way. Are they supposed to curve toward the front of the car or are they supposed to curve toward the back of the car?
 
I'll have to see if I can find the link, but I read somewhere that the direction of the slots doesn't really matter - it has to do with the direction of the vents inside the rotor. If the vents are curved or angled, the rotors should be installed to maximize the airflow through those vents. (Off the cuff, I don't remember which direction that curve should be.) If the vents are straight, it doesn't matter which side they go on - pick the way you think looks best.

If I can find that link I'll come edit this to post it.

Ninja Edit: I think this is it: http://zeckhausen.com/how_to_properly_install_rotors.htm
 
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kosteniuks17 said:
So I purchased a set of four new slotted and drilled rotors from R1 concepts and a set of 4 new calipers that I plan to paint red this weekend. I have my mechanic friend installing it all next week some time. So my question is which way are the slots in the rotors supposed to face. It seems like this was questioned before but no one had a legitimate answer. I just dont want my brakes to be squeaking cause I put them on the wrong way. Are they supposed to curve toward the front of the car or are they supposed to curve toward the back of the car?
Click to expand...
There's only one way to put the rotors on. The wheels will always roll counter-clockwise (facing the wheel). So whether it is on the driver's side or the passenger's side, it won't matter. You can't installed a rotor backwards.
 
rit14623 said:
There's only one way to put the rotors on. The wheels will always roll counter-clockwise (facing the wheel). So whether it is on the driver's side or the passenger's side, it won't matter. You can't installed a rotor backwards.
Click to expand...

OK That's wrong,... the passenger side rotates clockwise going forward facing the wheel. The drivers side rotates counter-clockwise going forward facing the wheel.
Same with directional tires,... they can only be mounted on the left or right side.
 
pcb said:
OK That's wrong,... the passenger side rotates clockwise going forward facing the wheel. The drivers side rotates counter-clockwise going forward facing the wheel.
Same with directional tires,... they can only be mounted on the left or right side.
Click to expand...

x2
 
You've gotta check the direction of the vanes inside the rotor. The vanes should feed the air out from the middle during forward rotation.
Check that link above.

Here's a quote:
For rotors with slots machined in the opposite direction as the internal cooling vanes, the slots should lean toward the front of the car. Bottom line - don't use the slots to decide which side to mount the rotor. Pay attention to the internal cooling vanes.
For slotted rotors with straight internal cooling vanes, the direction of the slots is totally up to you and what you think looks best. In this case, there is no wrong answer.
 
pcb said:
You've gotta check the direction of the vanes inside the rotor. The vanes should feed the air out from the middle during forward rotation.
Check that link above.

Here's a quote:
For rotors with slots machined in the opposite direction as the internal cooling vanes, the slots should lean toward the front of the car. Bottom line - don't use the slots to decide which side to mount the rotor. Pay attention to the internal cooling vanes.
For slotted rotors with straight internal cooling vanes, the direction of the slots is totally up to you and what you think looks best. In this case, there is no wrong answer.
Click to expand...

^^ This. For my stoptech slotted rotors the vanes in the rotor are straight so they can be installed either way. Stoptech was nice enough to include a note with the rotors giving you details on how to tell which way the slots need to face.
 
pcb said:
OK That's wrong,... the passenger side rotates clockwise going forward facing the wheel. The drivers side rotates counter-clockwise going forward facing the wheel.
Same with directional tires,... they can only be mounted on the left or right side.
Click to expand...
Ah you're right.
I recently installed Ate front slotted rotors where they are bi-directional.
My Powerstop rear slotted rotors are non-bi-directional. left-only, right-only.
So basically, the installer needs to look at the part number on the rotor's box to make sure it is the passenger side or driver's side.
 
My Brembos had slots angled/curved towards back of car and the R1's the slots angle/curve towards front of car and came with stickers on them saying which was l or r. +4 on the link info. The answer = not all are same and not same doesn't always equal wrong. It depends on the cooling vanes for the fronts then just match the rears to fronts since rears has no vanes.
 
I should clarify on the Stoptechs. They did have L and R stickers on them but if you read the note in the box it tells you that their solid rotors and their rotors with straight vanes are bi-directional. Only the rotors with swept vanes are directional.
 
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Alright awesome info guys thanks for clearing it up a bit. I checked on them and it seems that the air vents are straight vanes so I guess thats why they weren't designated to a certain side. I guess i'll put them on sometime this week. Thanks a lot.
 
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