TYRES (997 TURBO)

[fireblade]

Anyone have any opinion on tyres? My Pirelli P Corsa Rosso's need replacing at only 12,000 easy miles, rather disappointing. True I do a about four track days a year in a leisurely style but the Continentals on my previous 996C4S with exactly the same useage lasted to over 20,000 then I sold it!

On my last track day in the summer at Le Mans the car started to slide badly and the instructor said that the tyres had overheated as they were overpressured although I was running them exactly per the book. I let some air out but all this did was incur a lot of squealing noises and the TPI's calling for more pressure! It seems that Continentals are not available for the rear but Bridgestone are and I am loathe to run Pirellis again on grounds of cost. I realise that all tyres are a compromise and wear is dependant on individual driving style but my annual driving profile is daily commuting (about twelve miles a day) a couple of continental trips within the speed limits and three or four trackdays in a fairly leisurely fashion without hammering the brakes (although at my service last month I was told that I needed new pads and discs on the rear (not the front!) although these items were never required on my C4S !

There is probably lots on this subject somewhere but I couldn't find it!

Any info gratefully received.

Cheers

 

[Alex L]

Some light reading on tyres: http://www.carbibles.com/tyre_bible.html

I would say Michelin PS2's are the best tyres (if you can get them). I am currently trying out the new Pirelli N-2 rated tyres though that came out with the GenII 997s. They seem pretty good thus far but I haven't been out in them that much since December due to the weather.

 

[garyw]

I have the Bridgestones on mine and really quite happy with the tyres, however I've never got any more than 12K off a set of rears in any of my Turbos and thats with various makes of tyres!!
I did find my Bridgestone to get hot quite quickly and underperform on track (even when dropping the pressures) - or maybe its my driving style [&:] []
I do usually get 20K off the fronts..

garyw

 

[tscaptain]

I have always liked the Bridgestones for road use too, for both wear and grip (and no noisier than Michelins in my experience). Big price difference between Michelin and the rest now? But then I have a separate set of wheels/tyres for track use anyway.
On the subject of TPM's, which I have never had up to now (but will have soon![]) am I right in thinking that they can have two settings (Summer/Winter?) and in that case can one setting be for road and the other for track so that when you drop the pressure on track you don't get the warning?

 

[okellyt]

Firstly all 4 tyres need to be the same make or you could seriously compromise the handling, especially in bad weather conditions.

You didn't say if all 4 Prielli's needed replacing but if not replacing the worn pair might be the cheapest option.

Conti's wear best but don't grip as well and have some terrible characteristics in the cold - all the standard tyres on 911's are summer tyres and are not designed to work under 7 Centigrade. The envelope varies by tyres but the conti's seem to suffer more.

I had a set of conti's on my first boxster and got 34k out of the rears but I hated them, they didn't grip and had very temperamental characteristics in bad weather or near the edge of grip (euphemistic way for saying they let go without warning once it was cold or wet or if I was pushing it).

As the car gets more powerful &/or heavier tyre wear also increases. It also must be said as we get used to driving Porsche's our definition of taking it easy does tend to change and result in more rapid tyre wear. On my current 911 I got 18k miles out of my first set of rears, but that included very gentle running in, some serious motorway mileage and me learning to drive the car. The second set lasted 11k miles, albeit the cars power was up significantly.

12k seems a typical lifetime for a set of rear 997 tyres, especially the Turbo's. I have only driven a turbo properly with Pirelli's on them and I have to say I was impressed. Some like Gary like the Bridgestones, however these are supposed to be the quickest warning set of tyres of the 4 normally used on Porsche. I have Mitchelin's on mine and think they are the best compromise but the Prielli's and Bridgestones do have higher wet weather grip, the Mitchelins last a little longer and give fantastic dry weather grip.

Parting thought was some advice I had from from Chris at Center Gravity " Don't skimp on your tyres, those 4 little contact patches are what keep you alive and your car intact"

 

[fireblade]

On the subject of TPM's, which I have never had up to now (but will have soon![]) am I right in thinking that they can have two settings (Summer/Winter?) and in that case can one setting be for road and the other for track so that when you drop the pressure on track you don't get the warning?
[/quote]

Yes you can stipulate winter or summer tyres, no idea if this is relevant to the track though as I don't know what the different pressures are. It would probably be pure luck if the winter tyre pressures coincided with a suitable track setting. I use standard pressures per temperature in the handbook and these seem to adjust to the outside temp automatically. ie x psi at 0 gives y at 10 .

Thanks Guys for the valuable feed back

 

[fireblade]

Unfortunately it is all four which is why I am loathe to get Pirellis again.

Cheers,

 

[tscaptain]

ORIGINAL: fireblade

On the subject of TPM's, which I have never had up to now (but will have soon![]) am I right in thinking that they can have two settings (Summer/Winter?) and in that case can one setting be for road and the other for track so that when you drop the pressure on track you don't get the warning?

[FONT=arial"]Yes you can stipulate winter or summer tyres, no idea if this is relevant to the track though as I don't know what the different pressures are. It would probably be pure luck if the winter tyre pressures coincided with a suitable track setting.

I seem to remember someone, Bob F I think, saying that the OPC can set the TPM's to any pressure that you want so that you could have "Summer" = road and "Winter" = track - and you just tell them what pressures you want?

 

[garyw]

I seem to remember the very same Alan.
I've never changed my settings..

garyw

 

[fireblade]

ORIGINAL: tscaptain

ORIGINAL: fireblade

On the subject of TPM's, which I have never had up to now (but will have soon![]) am I right in thinking that they can have two settings (Summer/Winter?) and in that case can one setting be for road and the other for track so that when you drop the pressure on track you don't get the warning?

Yes you can stipulate winter or summer tyres, no idea if this is relevant to the track though as I don't know what the different pressures are. It would probably be pure luck if the winter tyre pressures coincided with a suitable track setting.

I seem to remember someone, Bob F I think, saying that the OPC can set the TPM's to any pressure that you want so that you could have "Summer" = road and "Winter" = track - and you just tell them what pressures you want?

Interesting!! Anyone have any ideas on track pressures?

i think that i would rather adjust the settings myself if possible! I would hate to keep having to return to the OPC to try different pressures!

 

[tscaptain]

I was working on the basis, Michael, that the desired track pressures were known and could be set into the TPM system by the OPC. You can then change from road to track pressure settings - is that done via the PCM or on the centre display? Alternatively just set the pressure you want and ignore any warnings from the TPM's!

 

[fireblade]

Yes it should be that simple!!

Unfortunately I have been fed tons of advice on track tyre pressures mostly contradictory and from owners of all sorts of machinery so I usually just use normal pressures hence no bleating from the TPI's which seem to compensate as the tyres get hotter.

Although I have not tended to play with the PCM, so far the only choice I have seen is "Summer" (the default) and "Winter"

I don't think that it is possible to set a bespoke pressure as an owner and visits to the OPC are not convenient due to my working hours and tend to be expensive!

Needless to say I have left everythng at default settings except for the clock!


I know that sounds terrible after two years of ownership but gone are the days when I could get a Mini engine out in 25 minutes!

Cheers

 

[pwebb]

Don't forget that your local tyre fitter can now fill your tyres with nitrogen (Lancerlot recommends that they purge the air out a couple of times to get as pure nitro as possible) and is very cheap to do (£1 a tyre at my local KwikFit). This helps stablilise tyre temperatures for track use.

 

[tscaptain]

Apparently Alex's Car Bible link (above) throws doubt on the whole nitrogen is better concept. The article claims "dry" air would have the same effect but I'm not sure where to get it from![]

 

[pwebb]

Yes, hadn't read that thoroughly, interesting site Alex. Still, found at last year's Welsh track day that tyres didn't heat up as much as I'd expected - though maybe not trying hard enough. Will invest in a digital guage and check more often!

 

[Lancerlot]

ORIGINAL: tscaptain

Apparently Alex's Car Bible link (above) throws doubt on the whole nitrogen is better concept. The article claims "dry" air would have the same effect but I'm not sure where to get it from![]

Moisture causes temperature fluctuations. N2 is a solution. There are other benefits but I'll start another thread rather than highjack this one. []

As regards track tyre pressures, acquire an infrared thermometer and take readings over the tyre tread area following a few quick laps. You're looking for even temps. over the entire width of the tread. Higher temp. in centre = pressure too high. Higher temp.at edges = pressure too low.

Hope this helps. []

Regards,

Clive

 

[fireblade]

As regards track tyre pressures, acquire an infrared thermometer and take readings over the tyre tread area following a few quick laps. You're looking for even temps. over the entire width of the tread. Higher temp. in centre = pressure too high. Higher temp.at edges = pressure too low.

Hope this helps. []

Regards,

Clive
[/quote]

Thanks one and all, I now have a lot to think about!

Clive, I just love the word "acquire" Where might I might find an infrared thermometer and how much? Please remember I live in Jersey and anything unusual here costs twice as much as in the UK despite no VAT! Sounds a great idea though but probably a bit too advanced for me. My idea of a successful track day is not breaking anything, not getting caught by Le Fliqs for speeding (cos I wasn't officer) and having a cracking party night afterwards and getting up without a headache in time to catch the ferry home! I also enjoy not winning the D... Head award which I had once for forgetting to press the Sport button, I was told that the award was for stupidly "fessing up to it"! I am glad I didn't mention that I had the aircon on and was listening to "Band on the Run" Nitrogen sounds fun and I will enquire but I have not heard of it being supplied over here although we use (expensive) nitrox for Scuba so Nitrogen must be around somehwere.

Now about these replacement tyres..........................................................

 

[Lancerlot]

Infra-red laser pyrometers are fairly common among the motoring fraternity nowadays.

If you wish to purchase one, it should be available from "any good tool retailer".

Both Sealy and Draper list them and there's quite a choice in the Demon Tweeks Mail Order catalogue. Prices range from around £35 - £150 and there are plenty on FleaBay too.

You asked for optimun track day tyre pressures and this is the best way to do it. []

Tyres? Michelin - no question. But remember, grip = wear and no grip = no wear. It's your choice. [8|]

Regards,

Clive

 

[tscaptain]

I found the equal temperature thing works ok for the fronts but is less reliable for the rears due to the proximity of the exhausts to the inside of the tyres and the subsequent heat soak. The inside third of the rears is always quite a big hotter than the centre of outer third.

 

[grover]

My OPC did the Pirellis for £1000 incl Vat fitted, balanced etc last year and that was the best price I could find. they had lasted about 13-14k miles probably, from memory.

No point complaining about the wear or cost, we are driving cars that once cost £100k plus (emphasis on ONCE)which are pretty damn quick so for me there is no compromise on the quality or type or cost for that matter of the little black things that keep me safely on the road. I must be alone in that thinking

D