[rob76turbo]

Okay, I had my sights set on a set of 17's" (7" and 9") Cup II's off a 993. I would run Toyo R888: 225/45/17 -F and 255/40/17 - R



Now however a good deal (and local to boot) has come up for a set of 18" (9.5" and 11"). I would run Toyo R 888: 235/40/18 - F and 275/35/18-R



So now the question, has anyone run both wheel sizes on the track and what is your opinion of each? I have heard that with stock HP, it is hard to run 18's. Are those tires 18" wheels / tires too large to run with stock HP?



As usual, thanks in advance for the feedback!!!

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[Eric_K]

9.5 & 11 will have to be the perfect offset to fit. I would try before you buy. Unless you are really serious I would stick to the 17's as they will be lighter and the tires will always be a lot cheaper - but you could fit a lot more rubber on the 18's.

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[Torbjorn968]

I would recommend running 17x9" all around on the car. There are several advantages:



- less understeer

- you can rotate tires around the car to even out wear

- you can have 2 spares in the back of the car even with a cage (and one in the passanger seat)-



These 2 spares will then fit anywhere on the car which is good thing because you can go to the track with 2 decent tyres, a very worn set and the spares. This will allow you to run get every mile out of your tires without being afraid that you will run out of rubber when you are at that event you have been waiting for so long. And if you end up in the gravel trap with small stones between the wheel and tire they will once again fit anywhere around the car (hopefully you do not have that problem on all fours). Or hit a curb.



Once getting serious about track days I have found it important to be careful about running costs to be able to maintain it where it counts. I would argue that the grip of the 255s is plenty, I believe Erik runs his car on 225s (due to rules). 255/17s all around or 265/18s all around seem to be the typical choice in the Swedish PCSR class 2 where the 968s are the most popular choice.



T

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[Cloud9...68]

[quote name='Torbjorn968' post='49637' date='Mar 23 2008, 08:16 AM']I would recommend running 17x9" all around on the car. There are several advantages:



- less understeer

- you can rotate tires around the car to even out wear

- you can have 2 spares in the back of the car even with a cage (and one in the passanger seat)-



These 2 spares will then fit anywhere on the car which is good thing because you can go to the track with 2 decent tyres, a very worn set and the spares. This will allow you to run get every mile out of your tires without being afraid that you will run out of rubber when you are at that event you have been waiting for so long. And if you end up in the gravel trap with small stones between the wheel and tire they will once again fit anywhere around the car (hopefully you do not have that problem on all fours). Or hit a curb.



Once getting serious about track days I have found it important to be careful about running costs to be able to maintain it where it counts. I would argue that the grip of the 255s is plenty, I believe Erik runs his car on 225s (due to rules). 255/17s all around or 265/18s all around seem to be the typical choice in the Swedish PCSR class 2 where the 968s are the most popular choice.



T[/quote]

Interesting input. I had never heard this before, but you make a lot of good points.

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[Torbjorn968]

I tend to keep 2 new tires in my garage waiting to be mounted after running a previous pair close to the cord, when they go on I order another new pair keeping six wheels rotating with 2 fresh tires alway waiting to be mounted.



T

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[TheMirror]

[quote name='Torbjorn968' post='49645' date='Mar 23 2008, 10:50 AM']I tend to keep 2 new tires in my garage waiting to be mounted after running a previous pair close to the cord, when they go on I order another new pair keeping six wheels rotating with 2 fresh tires alway waiting to be mounted.



T[/quote]



Good comments Torbjorn, what is the rest of your suspension setup?



Cheers,



-Mirror

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[Torbjorn968]

[quote name='TheMirror' post='49686' date='Mar 24 2008, 07:04 PM']Good comments Torbjorn, what is the rest of your suspension setup?



Cheers,



-Mirror[/quote]



LEDA suspension with custom damper curves (Swedish Touring Car engineer behind these), 1000 lbs springs at the rear, 800 forward. MO 30 sway bars, rear swaybar at hardest setting. 3½ degrees of camber forward, 3 at the rear. Next mod is a stiffer swaybar forward since a discussion with the race engineer in question suggests that what is seen us understeer might be turn in response.



For the purpose of evaluating my claims of 255s around as a recepie for good balance this is however not enough information. Last season I was according to the previous owner running 3 degrees of camber all around. When doing a corner weight setup for this season settings at the rear showed ½ degree of extra camber compared to the front which may have been a missalighment after about 10 offs last season. One can therefore argue that my feeling of too much understeer could be dueto a faulty setup of the car.



I have however not heard about a 968 owner with regular oversteer problems and my experience from my previous car with standard suspension also suggests that equal dimensions all around is a good thing. The typical comment on the Swedish 944 site is that "my car has good balance but perhaps a tad much understeer".



T

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[rob76turbo]

Torbjorn,



Thanks for the comments about your suspension set up. That is next on my list of to-do mods.

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[rob76turbo]

Ended up with the Cup II's. They cleaned up very nicely. They are at 5th Gear Motorsports in the DFW area patiently waiting for their new Toyo R888's.

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