Getting stoned in a GT4

[ghiblicup]

On my way to a Goodwood track day 6am so pitch black on a NSL country road. All of a sudden heard an awful noise from the front off side. Traffic behind me and nowhere to stop. Took me a minute or so to figure out what it was so slowed and shook the wheel back and forth gently and it stoped. When I could finally pull over found this...


Stones and PCCB’s Anyone else had issues?

On the plus side it was a great day on a very greasy Goodwood

[Mosdef]

Sorry to hear about the mishap but I can’t see any damage (might be the iPhone screen). The cracking on the disc looks normal to me and not dissimilar to the state of my discs on my Pan Turbo S.

Have you had them checked at all?

Having had a scored disc on my last Panamera, I occasionally worry about having PCCBs but life’s too short.

[MKnight702]

ghiblicup said:

When I could finally pull over found this...

A completely normal looking disc????

[Discombobulate]

I think I must be missing it too - what are we supposed to be looking at?

[sidicks]

Discombobulate said:

I think I must be missing it too - what are we supposed to be looking at?

Large scratch around the inner circumference of the wheel?

[ghiblicup]

sidicks said:

Discombobulate said:

I think I must be missing it too - what are we supposed to be looking at?

Large scratch around the inner circumference of the wheel?

Exactly!

It’s scored the inside of the wheel. It’s a deep one too.

[av185]

Collected a number of stones recently between the caliper and rear disc on my GT4.

Caused quite a groove which would probably have been terminal on ceramics.

This is why I prefer steels.

[JonChalk]

If that's actually machined a groove, rather than a surface scratch, it may have weakened the wheel by creating a stress concentrator, and taking a significant percentage of the total thickness at that point away.

[hunter 66]

Ohhh no , had 40 ft of flame behind my 911 when it let go things happen

[Koln-RS]

Surely that could happen with steels or ceramics. I had it on a Boxster with steels. Scored the wheel and I had to reverse to release it.

[Porsche911R]

Koln-RS said:

Surely that could happen with steels or ceramics. I had it on a Boxster with steels. Scored the wheel and I had to reverse to release it.

Have to be a brick if you had steels

The gap with the PCCB calipers to rim is small, the steels is large enough not to trap stones.

[Madadd]

Yes, I have the same issue. Same car with PCCB's and both my fronts have a perfect scored circles just like yours.

I got mine from a road up in the lake district that had just been re-dressed with a new top coat.

The gap from caliper to wheel is pretty bloody close!

[NBTBRV8]

I got a small stone caught in behind my backing plate with PCCBs. I knew immediately what it was and pulled over immediately, it took me 15 minutes to get it out trying all sort of things. I thought I was going to have to call a flat tray truck but it came out. Fortunately it didn't mark the disc.

[Phooey]

Porsche911R said:

the steels is large enough not to trap stones.

Sadly not. Very very common on Porsche brakes - OPCs words. Puts you off PCCBs a bit.


My experience https://www.pistonheads.com/gassing/topic.asp?t=99...

[Porsche911R]

Phooey said:

Sadly not. Very very common on Porsche brakes - OPCs words. Puts you off PCCBs a bit.


My experience https://www.pistonheads.com/gassing/topic.asp?t=99...

Different issue, we are talking about scores in the wheels , which is impossible with steels.

[I-Mac]

OP: Both my fronts are the same with both wheels scratched front trapped stones (I have PCCBs). Nothing much you can do tbh, just reverse back to clear the stone (mine never sees a motorway due to where I live). It has happened to me several times. No damage to the PCCBs but looks unsightly on the wheels.

[Fokker]

Yes Ive heard of this happening to the inner wheel but I don't hear of PCCB's scoring?
Is it right that they're so hard, they wear the stone down as against marking the face?

[Mosdef]

Fokker said:

Yes Ive heard of this happening to the inner wheel but I don't hear of PCCB's scoring?
Is it right that they're so hard, they wear the stone down as against marking the face?

I've asked a couple of OPCs and they both said there have been 'one or two' incidences of PCCBs scoring but they could hardly recall the circumstances....apparently. The only detail they gave me involved a car on a track day skidding sideways into a gravel trap and the owner continuing to drive it, rather than checking and removing the stones.

I have no idea whether the above is utter BS but there aren't that many reports I can find of owners having scored PCCBs or ceramic discs in general. The thought of one day having to stump up for replacement of scored PCCBs is not one I relish!

[Relic]

Happened on my GT3 with PCCB's two years ago. I have stones on the drive and one got stuck between the caliper and the wheel, it scored the wheel all the way around the inner wheel.

Fortunately I had the wheel insurance so that covered it. OPC (Swindon) told me I was very lucky it was not the disc that got damaged.

[Fokker]

Mosdef said:

I've asked a couple of OPCs and they both said there have been 'one or two' incidences of PCCBs scoring but they could hardly recall the circumstances....apparently. The only detail they gave me involved a car on a track day skidding sideways into a gravel trap and the owner continuing to drive it, rather than checking and removing the stones.

I have no idea whether the above is utter BS but there aren't that many reports I can find of owners having scored PCCBs or ceramic discs in general. The thought of one day having to stump up for replacement of scored PCCBs is not one I relish!

Yes googling Porsche PCCB scoring only brings up one result and that a very minor thing.

I'm not worried. If the wheel gets damages I really wouldn't be that bothered as its very easily repairable.