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Porsche 993tt brake disks.

I know they are directional due to the veined vents (no idea f this is quite the right term), however are they ever only for the left or right side, ie is the inner face of the disk different to the outer?

Both my disk rotate the same direction in terms of the shape of the vents and the hole pattern.

Just while cleaning out the holes (could not believe how much resistance some holes had and how much brake dust fell out) I noticed once side of the car the holes just look like a hole in the disk with a straight edge and the other side of the car the holes have a bevelled edge like they are counter sunk.

Unless the disks are designed to be left or right hand side mounted and I have two rights or say two lefts i cant think how they could be round the wrong wway or mounted on the bells/hats wrong with them being directional.

I guess when you buy original Porsche disks they are handed as the bell/hat will be mounted one side for left and one side for right, but is there a physical difference to the sides of the disk by design is what I really need to know.

Can someone have a look at theirs?

Anyone know enough to comment on this?

What side of the disk is the bevelled hole menat to be?

Both disks were just as blocked up with dust so it doesn't seem to effect that, so what is the difference designed for?

I think I have partly answered my own question and assume I have two slightly different disks, perhaps crossing a design alteration or something.

On closer inspection, the disk that has a slightly bevelled edge as if counter sunk has this shape holes both faces of the disk and the disk that has straight edge holes is also the same on both faces of the disk. it's very sutble.

A little mysterious, but I can live with that.

Sounds like one disk is more worn than the other, the Porsche discs are cast with the bevelled edge to mitigate the cracking issue with holed discs.

I'm sure Doug will tell you when you get your brakes done on Monday.

After the boiling issue you had I'm going for SRF brake fluid too.

Hope your reservoir holds up! Don't use up all the SRF!

Both disks seem to be worn the same, if it was worn enough for the bevel to dissappear the disk would be massivly worn and well below useable material.

Cleaning the holes really has to be a top tip anyway (read originally on RS246 of course) as they were nearly all at least 50% blocked if not fully.

The bevels do disappear Graham and the cracks join around that point so you have to replace them.

Perhaps you have a very worn disc and a newish one, or one is not OEM?

As you've said above, they are handed and directional.

Cheers David.

I was using a digi cam to get a view of the other side of the disk. On 2nd look I'm not sure that the other face of the disk isn't bevelled. As the caliper clamps a pad each side of the disk, I'm not sure why only one side would be bevelled and one one not?

I'll have a proper look next time the wheels come off.

Cracks are no where near meeting up at the moment thankfully.

Cool, there is a lot of meat on the discs, they last very well and are 'relatively' cheap at £ 140 each.

I got a set of 993 tt discs from euro parts in chester , they were £104 each , they do have different pt no's for left & right. g

grizz wrote:I got a set of 993 tt discs from euro parts in chester , they were £104 each , they do have different pt no's for left & right. g

Cracking price, is that +VAT?