Straight grooved brake disc direction

golfinger

Guest
I need clarification on which direction I am supposed to mount some new straight grooved discs on my Leon.

Below is a photo of the discs in question:

e40e_1.JPG


Now, on the front passanger side of the car, which way round should the grooves be facing?

I keep getting contradicting information from various sources, so what is your opinion?
 

golfinger

Guest
I have always put them on as per how that picture looks.
With the groves "going forwards"

I have heard this and people saying mount the other way. Also people saying that you can mount either way depending on what style of breaking you require - Passive/Aggressive. :confused:
 
Sep 29, 2008
835
1
Bradford
i fitted some of these to my leon same as in the pic, to be honest you can here a wirring noise under heavy braking, as if the discs are warped but with out all the car shaking its tits off and obviously it stops a hell of a lot quicker, not sure if it would ake the same noise it they were fitted the opposite way round:shrug:
to be honest i dont think it matters that much, but thats just my opinion/experience,
 

golfinger

Guest
Thanks everyone for your input. The "pointing forwards" direction as per the photo seems to be the consensus.

I also found this page that shows all the different disc types that seems to agree with the above:

http://www.apracing.com/info/info.asp?section=Disc+Face+Types_39

It seems straight grooved disks are mounted forwards, and curved grooved backwards - maybe this was where the confusion was coming from:

g_g8.gif


VS

g_cg8.gif


Will be fitting them and some DS-2500's this weekend and repainting my calipers while everything is off... pics to follow.
 

golfinger

Guest
as said you can mount them passive or aggressive but most fit them passive... ie pushing the air to the outside of the disc

So what direction is displayed in the photo above? Passive or aggressive?
 

Deleted member 20376

Guest
i fitted some of these to my leon same as in the pic, to be honest you can here a wirring noise under heavy braking, as if the discs are warped but with out all the car shaking its tits off and obviously it stops a hell of a lot quicker, not sure if it would ake the same noise it they were fitted the opposite way round:shrug:
to be honest i dont think it matters that much, but thats just my opinion/experience,

the noise is just the air in the grooves and drill holes when braking. i get the same, sounds a bit like a flutter noise.

i think it depends on the make of disc i think
mine said on the box left n right it also had a R and L on the back engraved in.
mine r fitted the same as the picture.
 

Willie

LCR Track car
Aug 6, 2004
8,939
1
Sunny Scotland
Sorry boys but if the discs are vented it has to be with respect to the direction of the vents.
Some discs have directional vents and other it doesn't matter.
Where the vents are not directional then you can mount these either passive or aggressive.
But 100% has to be with respect to the vents.
If the vents are round the wrong way you will be sucking cold air into the centre of the brake discs, the other way you are drawing the hot air way from the disc centre to the out side.
 
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