Wheel Options for Track Use

[Highwayman]

Haven't been on here for a while, but the warmer weather has got me thinking about getting started on some planned upgrades to my 944 S2 for a bit of fun on track in the Spring/Summer []. The coilovers and brake overhaul parts are all in the garage awaiting fitment, as are several other bits and bobs to get it up to strength for track day use, but I'm having a bit of difficulty trying to decide on wheels/tyre sizes and compounds.

I run the car on the road shod with standard Design 90s fitted with 205/55 Toyo T1Rs on the front 7" rims and 225/50s on the rear 8" ones. This is fine for the limited use that it gets, but I like to have a more interesting set up for track use, and possibly for fast road summer use. As such, I've managed to pick up another set of Design 90s and was thinking about a couple of options:

Option 1 - Fit the two 8" rims from my spare set with 245/45 Toyo T1Rs on the rear and move the existing 8" 225/50s onto the front. This gives me wider tyres front and rear than standard, but road spec tyres for track use

Option 2 - Fit the two 7" rims from my spare set with 225/50 semi-slicks on the front and the two 8" ones with 245/45 semi-slicks. This gives me a complete spare set of track focussed tyres, but only 7" rims on the front, rather than the 8" that I have seen recommended elsewhere on here for track use.

Obviously, there is a third option to fit semi-slicks to all four 8" rims and flog the 7" set on Ebay, but I would prefer to retain a normal road set up in some way shape or form. I could also change the wheels for something that would give more cooling to the brakes, but am not keen on this unless it really is a major issue.

Any advice gratefully received before I commit any (more) funds to this []!

Phil

 

[Lowtimer]

What I would do is a variation on your option 1: put new 225/50 T-1R on your spare 8" rims and put those on the front for track use, giving you a "square" setup that will be drivable on the road or on track - same make and size of tyres front and rear. It will help contain the basic understeer to which the car is prone. Also, it's a cheap option.

I would not move part-worn rear tyres to the front: they will be scrubbed all wrong. And on an S2, with limited torque, I don't think there's a lot of point going to super-sticky 245/45 on the rear.

 

[amrbose14]

Phil,

it's always seemed to me more logical to think about track/road tyres as one set which can be pretty low on tread, suitable for dry track days, and another set which is in good nick, and only used on wet tracks and on the road. This way also, one wet set turns into the next dry set! In that context, I'd have thought running different wheel sizes would present anyne setting up the suspesion geometry with a challenge. Which set do you optimise for? If you optomise for the dry set up then you may end up with a poor set up for wet tracks. On a wet track I find the flip between understeer and oversteer very pronounced. I wouldn't want it any more nerve-wracking.

I also was under the impression that suspension set up could deal with most of the understeer (at the expense of increased tramlining tendencies) and that ultimately it was grip at the back which was limited.

On the other hand if I'm wrong and your ideas are sound, then let me know so I can copy you!

cheers
Chris
--------------
87 220T

 

[Highwayman]

Thanks guys []. Two different opinions about wheel sizes/set up, but both in agreement to stick with road rubber, rather than semi-slicks. I like both ideas actually []. That's why I posted for suggestions []!! Keep them coming...

Phil

 

[chrisg]

Phil

I think your option of 8" Toyo's all round will be a good solution. This will give you good levels of grip, help with the understeer and allow you to push the car hard whilst finding the limits.

Yes, semi-slick tyres will work well with coil over suspension, but you'll generate a lot of grip, potentially over heat the brakes and put a lot more wear and tear on all the suspension components. Semi-slicks will wear quicker and if you generate very high cornering forces you may well be into oil surge issues. In addition, has your car got an LSD ?

My advice based on my own experiences of racing and track days, is that for the later sticky good road tyres are sufficient to have fun whilst leaving a margin of error, human, car performance and mechanical wear.

Chris

 

[Diver944]

The best performance upgrade for trackwork bar none for our cars is to fit a set of super sticky tyres!

When I used to track my S2 I had a spare set of standard D90's with full race slicks that were actually slightly narrower than the road rubber. The grip, cornering and braking were simply outstanding when compared with any sort of road legal tyre and they were in a hard compound. I got 10 trackdays out of the rears and 6 out of the fronts before the outer edge wore to canvas.

Back then they were the control tyre for the Porsche Cup series so you could get a full set for under £300 []

If you can find slicks in a suitable size at a reasonable price I would go for that and you can fit a full set in the boot whilst you drive to the track on your road legal tyres. Failing that you need to get a set of road legal track rubber - Toyo R888's, Kumho V70, Dunlop DZ03G etc

 

[Highwayman]

Hmm, seems like much of this is down to personal opinion []! I have had semi-slicks on previous cars and thought they they were great for track days and the occasional fast road blast in the summer, but I take the point about extra load on the suspension components and brakes. I also like the advantage of having a complete spare set to take and fit at the track, as Diver944 suggests, although I'm not sure that I want to go as far as full slicks [].

I think that I'm moving towards a full set of spares (7" fronts & 8" rears). Rather than go for R888s or the like, does anyone have any experience of Toyo R1Rs as a halfway house? They seem to have good write ups, but interested in any Porsche experience. Also, what about fitting 225/50s to both the front and rears, despite the different rim widths? Would the extra width of tyre on the front be worth it to help reduce the understeer, or would it be better to stick to the 205/55 standard fitment?

Sorry for all the numpty questions, but I like to do a bit of research before I commit the readies.

Phil

 

[Neil Haughey]

You want to get the widest tyres you can on the front, ideally for maximum grip one would run 245's all round or failing that 225's all round.

 

[edh]

My preference was for 225's all round rather than a staggered setup (I would have gone 245's with the next set) - worked fine on my Turbo with P Zero C's and would be more than enough grip for an S2. The balance feels much better and the back end moves a touch under braking as you turn in.

Track tyres give you much more pace but as Chris mentioned, you do stress the car more & will need good pads / cooling .

I think you may have more tyre options on 225/50 compared with 245/45 as well. Sorry I have no experience with the R1R - seems quite expensive though.

Toyo website lists permitted rim widths as 6.0 to 8.0 for 225/50 so you should be OK with the 7's on the front.

 

[Lowtimer]

Look, a lot of this depends on whether you care about how fast you are on track, and that is a matter of individual personality and how you get your kicks.

I haven't had the pleasure of meeting Paul but am a great admirer of what he did with his car - a truly dedicated development effort. If you have seen Paul'sYoutube videos, and witnessed the amount of development effort and money that he put into LIL, it is abundantly clear that he does not intend be be overtaken by anything as low-rent as a 997 GT3. While he is (of course) not actually racing on track days, the outright performance of the car is important to him. I'm sure he will correct me if I remember it wrong but I believe LIL, a 3.2 turbo, ended up with more than twice the rear-wheel horsepower that any S2 will deliver, and with the rest of the car developed to suit that.

But I'm not that competitive, and when I go for a track day I don't really care whether I am faster than anyone else. I just like to try to drive as well as I can, taking the opportunity to work in a part of the car's capabilities that I don't think it would be smart to try to use on the public roads. I want to have a nice handling balance and good feel and enjoy the whole thing as a kinetic experience, just like going out for an early morning run on the beach. I can have fun on road tyres in a way that might leave Paul gnashing his teeth with frustration. On the other hand he would be able to drive away from me at a quite amazing rate of knots, and there would be nothing I could do to keep up.

Both approaches work, they just work in different ways and give different results. If you want to be seriously fast then Paul's advice is totally on the money: tyres optimised for the track will definitely give you shorter lap times. But if you just want to blow the cobwebs out in a safe environment than you don't need to go to those lengths. Up to you.

 

[blease]

I got good advice on here a while ago about rim sizes. My car came with 8 inch rims all round and I was advised to stick with that for track day work. At the one track day I have done, the front felt fantastic...very direct, stable and accurate. The rear was all soggy but thats a different story. Will be heading for a coilover I think. But I fully agree with Lowtimer. You just have to know what your aims are. Mine is to have fun with a good feeling car and the S2 is more than a match for my 996 in that regard.

Mindyou, wouldn't mind trying some slicks out!

 

[MarkK]

For anyone wanting some cheap sticky rubber some Toyo tr888 half worn tyres are available in the the parts section...
(absolutely connected to the person trying to sell them)[]