kiwi 911

Ooooooh - OK, I have been corrected.................

Back into my box................

Macca

Come on Buba. You love being corrected. You didn't put that 15 months old piece of well researched and highly empirical data up there for me to see without expectations of a retort did you? Mate I know your fetish for high heels and being corrected. I saw the stilleto marks on the timber around the stove at your place. I know Jenny doesnt cook in heels!

As a small retribution I will send you the picture of that girl breaking into Dougs RS60 yesterday afternoon. The administrators gave me a warning that i would be given a "2 week holiday from Rennlist" if I posted it again! Frankly my wife would pay them to ban me from here!

Macca

Buba. Your mail box is full!

John McM

Just read tire rack advice that Michelin MPSS should not be tracked hard, which puts me back into the track tyre camp.

The standard sizes have rolling circumferences of 2036mm and 2099mm, front and rear respectively.

I far prefer specific wheels for track and road so will look for a set of 18in wheels. I will likely go with Z221 as I know they are competitively priced in NZ, relatively, and I like them on the track. I will go with 235/40 R18 and 265/35 R18, dependent on availability.

Anyone know of some 18" OZ or similar for sale?

Macca

John. MPSS cant be used on track? WTF!!
I think many guys in the USA & UK on RL would disagree. Obviously they are not a R comp but they have been used extensively on track for years by guys doing DE, autocross etc in the states. Neil and Richard have run them extensively on their GT3s in NZ and although they are no where near as quick as TROFEO R or dedicated R comp they are just fine on the track. Ive never seen any Michelin factory literature to suggest otherwise.

Good idea with 18 OZ and Z221 tyres. that's the exact combo/size I run on the 993....except the 265s were out of stock last time I checked. Let me know if that's changed. They will be a good 2s a lap quicker than MPSS on the track. Id imagine those should put you firmly into low 1.17s at HD :-)

John McM

http://blog.tirerack.com/blog/bens-b...ct-track-tires

Street Tires

Some people run their cars on the track with the same tires they use on the street. If you're already driving high performance tires, that set may work for you on the track. This scenario works best when you're attending beginner driving schools, casual lapping days or other events where the focus is more on polishing your skills rather than setting fast lap times. Street tires are not recommended for track use, and driving them in a track environment will most likely void their warranty. Keep in mind that if you overdrive them into corners, you could easily render them useless after only one day at the track. An example of this type of tire is the Michelin Pilot Super Sport.

John McM

While Tire rack is possibly a bit over the top, my impression so far is that the MPSS degrade noticeably over a 15 minute session so longer sessions could trash the tread quickly.

Whatever the case, I'll get pads and track tyres before going out again.

Macca

John. Sorry mate nothing new here. Its a generic statement we all knew. Its not specific to MPSS and you could swap it out for anything that isnt R comp....

Street tyres are not optically designed for the track. If it is very hot and you are driving very hard you may chunk them because of tread block depth etc. The side walls are generally not a stiff as they are built for compliance and low noise.

I didnt realise your strategy was to use MPSS as a track tyre. For occasional track use sure now worries. Lets face it we are not from USA so once a month is actually occasional!

If you want to run one set of wheels/tyres, have a low hassle life and get 90% of dedicated R comp performance whilst 90% of MPSS year around road performance then buy yourself

MICHELIN PILOT SPORT CUP 2

http://www.tirerack.com/tires/tires....C2XL&tab=Sizes

These are they tryes Ive done 10,000 km in all conditions from snow to summer NZ, track and fast road work on my GT3 and they are factory on GT3/GT4 and 991 GT3RS. They are bloody good. Almost as good as Z221. Read up on them you will see. Around 3K a set landed and they have them in your sizes...

Macca

[QUOTE=John McM;12067143]While Tire rack is possibly a bit over the top, my impression so far is that the MPSS degrade noticeably over a 15 minute session so longer sessions could trash the tread quickly.

Whatever the case, I'll get pads and track tyres before going out again./QUOTE]

Talk to Neil John. They are very pressure/temperature sensitive and the carcass will heat up quicker than an R comp. They are a road tyre. Ive just had them fitted for the Targa. They were my SITT road tyre. Richard had them fitted for the SI Targa as a road tyre and Neil uses them as a wet/damp track day tyre.

I never thought you were contemplated using them on the track. Ive never recommended them for the track.

Do yourself a favour. before you jump in boots and all read up on MPSC2. They make it in your size? and its 1700 USD a set. You could use these for everything you need. They are on the new GT cars and have radial grooves. It would be way easier to not have to change tyres or wheels etc for track days. You could do entire NI/SI TT on these without lifting a nut wrench.

John McM

That may well be the best solution. I have too many tyres as it is.

Macca

Ditto. They are heavy dirty and they take up space!

996tnz

Mine have their own ramshackle shack, but we still need to run a few more Ardmore gymkhanas to finish the annihilation of the dodgier ones.

Not sure about your car but a reputable car magazine did a series of back to back handling tests comparing the standard 225-40-18, 295-30-18s on the 996 Turbo against the same Turbo with the same model tyres, but lower profile on 19 inch rims. Standard set of tests - skidpad, slalom, braking etc. Can't remember if also tracked.

They were surprised to find that the 18s outperformed the larger rims with the lower profile equivalent tyres, then figured that Porsche must've tuned the car as a system. As you likely know already, the smoother the track surface (and kinder the kerbs if you're a hopper) and the more advanced your suspension (eg magneto-rheological etc as used in new Ferraris on down, or nice shiny JRZ, Motons etc) the more performance you'll stand to get from lower profile tyres.

Bumpier situations benefit from deeper sidewalls - as seen from rally cars to monster trucks.

IMHO, slightly lower profile on wider rims, while maintaining a similar sidewall height is a pretty safe track bet though (space and road legality allowing). But if as long as you customise the rest of your suspension to suit, a lower profile should track better. It does depend on how optimised your original package was though. On my old balloon-tyred 928, just going from 15s to 16s transformed the car.

RS ZWEI

Has anyone else heard the rumour that Tony Quinn might be purchasing Taupo race track?
I heard it could be going unconditional this Friday?

John McM

Yes and closing the track for renovations

996tnz

Happy to hear it's Tony who is involved but had gotten an email a while back trying to rally a defensive bid. Some large existing user groups were concerned about the closedown period and the likelihood of price hikes on re-opening. Hopefully it all works out for the best.