Discussion
Why are there so many reports of drilled brake discs cracking on Griffs and Chimps?
Aston, Porche, BMW etc all use drilled discs. And the newer Tivs for that matter, and they can't have any problems, or they wouldn't use them.
Is it the smaller disc/pad size of our cars or just that the quality of the disc isn't as good? If so, can you buy better quality drilled discs (of a standard 260/273 size)?
Aston, Porche, BMW etc all use drilled discs. And the newer Tivs for that matter, and they can't have any problems, or they wouldn't use them.
Is it the smaller disc/pad size of our cars or just that the quality of the disc isn't as good? If so, can you buy better quality drilled discs (of a standard 260/273 size)?
I have drilled and grooved on my Griff. They were supplied by Peninsula. I'd heard lots of stories so asked about cracking and was told that they had fitted these discs to a number of regularly tracked cars without problems. I've attended half a dozen or so track days with them and everything's fine so far.
Brake wear is quite dependent on brake technique/style though as different people get different results. HTH
Brake wear is quite dependent on brake technique/style though as different people get different results. HTH
Just don't do it. I've seen too many cases of fatigue cracking, some leading to catastrophic failure (not on my car fortunately). If your brakes aren't getting hot then the holes are doing you no good and are just causing noise, pad wear and dust. If they are getting hot then the holes are a danger and you would be better off with grooved discs. Unless you're getting the very expensive discs with the holes cast in, I'd say just don't risk it.
So, one 'fitted loads, never seen any problems' answer and one 'seen loads that are cracked, don't do it' answer.
Hummm.
Anyone else?
What is the difference between the drilled discs we would normally buy (EBC etc) and those supplied on other high performance marques and newer Tivs?
Is it that they are cast with the holes in and therefore don't crack? Are they much more expensive?
If most performance car manufacturers supply their top end cars with drilled discs, surely they can't all be wrong and are fitting them just because they look nice.
If there are there there is an increased tendency for cracks. I have had them and have had a problem once when a 3 inch crack appeared. Caused by local overheating when a brake calliper partially seized.
Very dependent on driving style like most things brake wise. Some people don't see issues while others do.
Very dependent on driving style like most things brake wise. Some people don't see issues while others do.
used to get cracked discs on new sl's and s classes
when i worked at merc's but it was normally down to the driver and overly aggresive braking,as was only a very small percentage that cracked.
ive had drilled disc's on cars before and had no prob's bar 1 set which warped but that was due to not bedding them in properly in the first place.
i have just fitted a set of black diamond drilled and grooved disc's to my griff so will post any grief that happens to surface
when i worked at merc's but it was normally down to the driver and overly aggresive braking,as was only a very small percentage that cracked.
ive had drilled disc's on cars before and had no prob's bar 1 set which warped but that was due to not bedding them in properly in the first place.
i have just fitted a set of black diamond drilled and grooved disc's to my griff so will post any grief that happens to surface
AFAIK, drilled discs have a reputation for cracking, period. Not just a problem with TVR's!
I'm no metallurgist, but I'm guessing that manufacturer's like Porsche are very careful about specifying the quality of the discs they are drilling, whereas quality control on aftermarket discs can be limited, and at worst I'm guessing that there are companies out there who are simply taking a standard Ford-spec (read budget) disc and drilling lots of holes in it.
I'm no metallurgist, but I'm guessing that manufacturer's like Porsche are very careful about specifying the quality of the discs they are drilling, whereas quality control on aftermarket discs can be limited, and at worst I'm guessing that there are companies out there who are simply taking a standard Ford-spec (read budget) disc and drilling lots of holes in it.
Got drilled & grooved discs. They cracked very quickly after fitting, with 2-3mm cracks on about 75% of the holes.They have not however grown further. I,ve done 18k miles & 6 trackdays on these, the last being Silverstone GP. I check the discs regularly to see if the cracks are growing.HTH
Johno & Griffdude, what make of discs do you have? It would be useful to get an idea of which manufacturer's discs have had no problems and which have shown a tendany to crack.
Loose cannon, can you keep us informed on the black diamond discs. They seem very popular at the moment - several Chimp owners have just fitted them.
Groucho, Penninsular use EBC I think. Let us know if they stand up to the abuse!
I don't do a lot of track work and would like to get some drilled & vented discs, just a case of which ones! (In case anyone asks why - because I am shallow and I think they look nice! I was a little reluctant before as all I had heard was bad things.)
Oh, and if anyone can remember the part number for their discs that would be handy too (I'll pass it on the Balistic Bannana for inclusion on the alternative parts list on the griffith pages)
Loose cannon, can you keep us informed on the black diamond discs. They seem very popular at the moment - several Chimp owners have just fitted them.
Groucho, Penninsular use EBC I think. Let us know if they stand up to the abuse!
I don't do a lot of track work and would like to get some drilled & vented discs, just a case of which ones! (In case anyone asks why - because I am shallow and I think they look nice! I was a little reluctant before as all I had heard was bad things.)
Oh, and if anyone can remember the part number for their discs that would be handy too (I'll pass it on the Balistic Bannana for inclusion on the alternative parts list on the griffith pages)
Again I have the Peninsula discs and they have been hammered over 3 years and are fine.
If the holes have any flaws in them they do act as crack propigators but so does any other impefection. Believe me they are perfectly good and have 2 benefits. One is cooling and the other is to release the air trapped under the pad when it comes into contact with the disc.
I will say that you should check them regularly as with any brake component. They can fail as did my "groove only" discs. The groove acted as the crack propigator.
By the way in the aircraft industry if a crack appears you drill the end of it to stop the crack!
If the holes have any flaws in them they do act as crack propigators but so does any other impefection. Believe me they are perfectly good and have 2 benefits. One is cooling and the other is to release the air trapped under the pad when it comes into contact with the disc.
I will say that you should check them regularly as with any brake component. They can fail as did my "groove only" discs. The groove acted as the crack propigator.
By the way in the aircraft industry if a crack appears you drill the end of it to stop the crack!
IPAddis said:
I'm going to have to check mine now, never heard of this before. I got some from Peninsula about 18 months ago. Oh, I won't bother, it's due for a service on the 3rd.
No it's not, mine's in Peninsula being serviced on the 3rd?!
Ian A.
Certainly is, been booked for a couple of months now.
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