Directional brake rotors

[dxhall]

After locktiting the new rotor bolts on the VFR wheels, I noticed that there are (very) small directional arrows on the rotors.  These rotors, though, have holes (not grooves) and appear to be symmetrical. Any idea why these rotors would be directional?  Needless to say, with a 50% chance of getting it right by dumb luck, I didn’t.  I really don’t want to remove the bolts.

[Turin]

I think you're probably safe.

[Sye]

Disks and pads wear into each other and become a pair. If you have the disks on the wrong side you will lose quite a bit of brake efficiency. In any case, the manufacturer wouldn't put a directional arrow on the disk unless it was important. I never take risks with brakes and tyres and it only takes 20 minutes to put right.

I would definitely correct this before I rode the bike, but ultimately it's up to you. Good luck.

[Dukedesmo]

Unless the carriers are a different design to take the loading then, I would think the arrows are probably there so that if you remove them anytime you get them back on the same side of the wheel as before?


I don't know that for sure though and I've never seen/noticed any such markings on any bike I've worked on but there are some high-end discs that have directional carriers, such as Braketech   https://braketech.com/axis-cobra-stainless-rotors/

[kballowe]

Maybe they're there to keep ya from mounting tires in the wrong direction. 
Who knows?

https://www.r1concepts.com/cms/index/which_rotor_is_considered_Left_or_Right_side

[kirby1923]

I have a '97 VFR and Although the  Rear wheel has arrows to assist you when you mount the tire (which is directional) however I have never noticed arrows on the discs. After years ,(bought new in "97), of mounting my own tires . I have never noticed any directional markings for the front.
Curious. ??
:-)

From the web:

Directional vs. Non-Directional Brake Rotors
Most replacement Brake Rotors are not directional. They can be installed on either side of the vehicle. However, some performance rotors are meant to spin in a specific direction.

If your rotors are directional, they will be marked. It could be a sticker, a tag, or stamped into the metal. Also, check the instructions that came with your rotors for proper installation.

If you don’t have the instructions and the rotors are not marked, keep reading to learn more.

What makes it a directional rotor?
The cooling vanes in a Vented Rotor determine if it is directional. If the vanes are curved or tilted, it is a directional rotor. If the vanes are straight, like the spokes of a wagon wheel, it is non-directional.