Macca

:-)

Pel

Dumb question, what's the danger? Sounds like the new ones need to go on.

Maxem

I'm not sure there is danger, just lower grip levels than a fresh set but I don't think they become unpredictable or anything?

Pel

I'm guessing the grip level on an old r comp would be the same, or better? Than a street Tyre? The flat spots make it easier to lock a wheel, its all learning though.

RS ZWEI

Is that the ex drug dealer GT3?

Macca

Im actually a little bit surprised no danger is perceived. Maybe Ive been spending too much time on the RL track forum or GT3 board.

My personal view is that tyres and brakes are the greatest safety devices you have at the track after helmet, suit, harness and cage.

Personally Id never run a 10 year old road tyre at the track, let alone an R comp. R comp tyres have a shorter shelf life due to a number of factors. There are oils and emulsions that age at different rates withing the compound.

My concern is not to do with grip and everything to do with the load the sidewall will endure before the tyre fails. There is also risk of delamination although this can happen to a new tyre too as John B found out a few weeks ago.

Each to their own I guess, but if you break mechanical costs per hour of track over the life of key wear items (gearbox, clutch, bearings, bushes, struts etc), and you have a set of new tyres on hand why loose life cycle rebuild $$$ to put up with substandard rubber that might have a 30% higher chance of endangering you or the folk behind you on the track? Sure the chances f it happening are very small but the way I see it you are doubling those small chances with aged tyres with compromised braking ability.

Pel, Im not sure what you will learn from flat spotted 10 year old rubber that has probably inconsistent tyre to tyre due to storage conditions/temps etc. If your stated mission is to push you car to the edge of your/its current performance envelope then possibly an idea to fit the new tyres and be the best you can be.

No intention to offend and no "skin" in the game either (well not on the 12th that is). Just my POV. Id be a bit surprised if it wasnt shared by others...

996tnz

Grip may still beat new streets Pel, but structural integrity likely wont. Maybe R-comps hold up better than streets but I suspect they actually go off quicker. My reticence to use old tyres for the regularity trial - before realising I'm away that first weekend anyway - was not their handling (still have the old 10 inch rims and Nexen 265s on the 996T that I threw on for the Gymkhana at the moment) but rather the risk of an old hardened tyre suddenly failing at the sidewall or cracking across the tread and delaminating while flat out coming into Turn 1.

One of the outcomes of the Carrera GT crash investigation that killed Roger Rodas and Paul Walker was that the car was being driven hard on 9 year old tyres.

Even for bog standard motorised shopping carts, tyre companies don't recommend running tyres older than 10 years and many recommend no older than 6. Porsche also say that tyres over six years old should not be used on their cars:

http://files2.porsche.com/filestore....8-0361f33bc081

The actual potential life of an individual set comes down to use, storage etc but the above guidelines are a start anyway. Bit more background here:

http://www.edmunds.com/car-care/how-...our-tires.html

996tnz

Snap - simultaneous post, LOL

Pel

Fair enough guys, no offence taken. Will chuck some new rubber on.

John McM

That's good. Wouldn't want to spoil the photos. If it's sunny I might get some photos to use at the 19th get together.

Meanwhile Herman has reached a milestone. Gearbox and engine back together and clutch fork successfully installed. Dave's hoping his cnc billet valve covers will arrive soon and it sounds like Autolign couldn't resist looking at the RUF Bilsteins before they said they would. It appears that the bump stops have taken a pounding. Now to see what else is worn.

nzskater

Pel, you and Dave definitely taking it to the extreme as far as tyre age is concerned. Mine are 1.5 years/18k km/5 track days old and I was feeling bad for still running them. Main concern is grip with relatively young tyres - they go off much quicker than the first couple of days - but they're relatively consistent now.

kiwi 911

100% agree with Macca and Walt - just not worth the risk, I'm sure you can run 10yr old brake and engine fluids too??

IMHO you are being silly Pel..............

Dave is Scottish - enough said..........

John McM

Dave is more Dutch than Scottish...same stereotypical attitude to spending money though.

Macca

Could be better to be safe than sorry. Last year Sean S had a blow out on an aged R comp at Puke and took out his left rear quarter panel on his 964 track car. Pretty scary however and most who saw it said he was a very lucky man. Tyre was 4-5 years old.

Good news is on the new rubber you will be worrying the 964s :-). Would make a good photo op I reckon...

911wings

Question for all NZ folks. I am coming to visit in February to the North Island. I would appreciate any ideas for things to do and see. Planning a bit of a fishing trip, will not be bringing my 964. Forgive my ignorance but are there any tracks I should go see?