The time has come to replace the tires on the GP.

I have standard setup - Suspension lowered to max, standard rims.

The car is used mainly for track days, and the occasional breakfast run, so no need for a proper road tire - the semi will be fine.

The question is size !

As you know the standard size is 215/40/17

Semi Slick tires are hard to come by here in South Africa, and the size available is 225/45/17 (Dunlop 17" 225/45R17 DZ03G H1). Does anyone have any experience with this size ? Will it fit the rim ? Will it touch the bodywork / suspension ? I don't want to add spacers etc.

Any advice on tyre pressures for the track ?

Any help would be appreciated.

 

I ran 225 45 17 in Bridgestone S-04 Poles on two 2011 R56S's Sport Packages as daily drivers with 36 PSI, no clearance issues at full suspension compression.

So they do fit at standard ride height, but that's all I can tell you.

 

That is a big tyre, and actually an uncommon size.

I don't know about SA, but 215/45/17 is a much commoner size for semi slicks (at least here in Australia). You can get loads of semis in that size, kumho v70A (ie same tyre as stock but different size), dunlop dzo3g, yoko ao50, toyo R888 amongst many others. If you don't have much choice consider importing them. Demon tweeks sells quite a good range and not that expensive to import.

215/45/17 fits fine and works well.

Dunlop DZ03 is a good tyre, and hard is the best compound for combined track and street use. The dunlops are very loud compared to the kumhos, a lot of tyre roar. Same with toyos and to a lesser degree yokos

Pressure depends on the tyre. Out of the above, dunlop and yoko 32psi hot, kumho and toyo 34 hot. By this I mean hot into pits pressure. To get these pressures I start around 22 front and 26 rear cold on the first out session. For less experienced or aggressive drivers probably start around 28 front and 30 rear.

 

Robbo it was recently suggested to me to run 2 lbs less than the front in the rear tyres on the track. Interested in your opinion on that and just curious as to why we would run different pressures front and rear. I have fixed camber set at 2.1 on the front.
I've got the Nitto NT01 in 215/45 R17 for the track. They are noisy on the road even at low speeds.

 

Thanks for the assistance.

I did a little more looking around locally - and may be able to get some toyo R888. I just need to confirm price and size locally.

Any feelings on Toyo R888 VS Dunlop's DZ03G ?

Thanks again.

 

The dunlop is a better allround tyre, slightly quicker (around .25s/km), better in the wet. However, the toyos are not bad, they wear extremely well, and tolerate heat cycles well.

If you are racing and the last 0.5s a lap is important, then the dunlops are better. If you are just enjoying track days and drivng on the street then the toyos are a perfectly good tyre.

 

The pressure you run depends on your setup, driving style etc. I have spend a lot of days at the track testing pressures and temps with pyrometers to get to my own personal ideal setup.

However, it sounds to me that if someone is saying to run a lower pressure in the rear they are probably trying to dial in a certain handling behaviour by changing the handling characteristics front vs rear, eg trying to dial out understeer etc

 

Thanks again for the advice.

I did find the Toyo R888 (but they only had 225/45/17 ) and they were about 80 USD more expensive than the Dunlop.

So I am going to have to try the Dunlop 225/45/17 - I have a track day next weekend, so no time to import.

Besides the Dunlops are 175 USD including all taxes - to import would cost more.
Shipping to SA is 400USD - lol.

Just hope they don't touch the bodywork