Are brake discs directional?

I recently discovered that my right hand brake disc is warped on my 05 trackbike so my question is....Do I need to replace it with a right hand disc or can I use another left hand?
I've seen the directional arrows stamped on the disc and I'm unsure about the sequence of drilled holes in it. Other than this they seem to be identical so would it be detrimental or even dangerous to use the wrong hand?

thanks

 

Yes they are directional the arrow should match the arrow on the wheel ( which if the tyre has been fitted right should match the tyres rotation). I don't know why tho ?
That said I know with swapping wheels n disc on the track bike I have used them incorrectly but never noticed any difference in braking performance ??
I'm sure someone will give an exact explanation as to why

 

Always had them rotating correctly in the past but would like a definite confirmation as to whether it's ok to change over. Not sure who would be qualified to tell me.....Arthur maybe?

 

Very interesting vid Jay, suppose I'll just have to keep hunting for a right hand disc then.

 

It doesn't actually say why they are directional so doesn't really answer your question.

I suppose it's to do with stress fractures if the loading through the Disc is put in reverse to how the Disc was designed?

 

I know EBC aren't directional. What you got on at the min? Time for an upgrade maybe, get the pair?

 

James, I have a couple of sets. The ones in question are standard discs and other than the drilled holes pattern, I can't see any reason not to swap them round. I bought a spare set of wheels that came with discs but unfortunately they had 06/07 discs fitted. These are 320mm instead of 310mm so I bought a Brembo caliper adapter kit to allow me to fit them to the bike. I'm due to test these on Wednesday at Oulton. Given that they are slightly bigger means that they are a form of upgrade.
I also have a Brembo master cylinder fitted and don't feel the need to go down the route of Brembo discs or wavey discs.
I have three sets of wheels and two sets of discs so I'm looking for another set, it's a real arse swapping the discs over between track sessions!

 

Thread on the for sale section with discs for 04-07.

I've just bought EBC discs and pads which are non directional. You could have had my right disc but that's shagged too.

 

Just took a look Glynn, £130 seems a bit steep to me. Seen cheaper on Ebay, I'm not desperate yet. Thanks for the heads up.

 

You could always get it straightened.

I recently took the front wheel from my trackbike to these people to have a dent repaired. While they had it they found one of the disks was slightly warp so they fixed that at the same time for no extra charge. Great service as I might not have noticed until I got to Almeria in a months time.

Motorcycle Frame and Wheel Straightening Experts - Maidstone Motoliner Ltd

 

If a disc has the arrow they are rotational if no arrow they aren't

 

I second that these guys are really good, took a buckle out of my wheel once. Bonus is they are 10 minutes from my house.

 

what da! never knew this was an option!

I've just bought some Brembo HPKs to replace my warped OEMS!. Guess I can get them straightened and have them as spares or sell em on.

 

I've used these guys myself years ago when I had my 929 but wasn't aware they straightened discs as well!

 

Didn't know you could either!!

 

Will give them a ring tomorrow, fed up of hearing one of my discs groaning every time I brake

Thanks for the tip off

 

Kentblade, I'd be very interested to hear the outcome if you decide to let them sort it mate.

 

Hopefully will have an update soon, as I am dropping my car off in Maidstone next week, and it would be the perfect time to get the discs looked at if they have a space.

 

I had mine done week later they were ball up again so got SH pair I'd only buy pairs but hay Ho some makes have arrows so e dont