I'm a relative newbie, but I have a set of 17" wheels I'd like to mount competition tyres on for a combination of track events and auto-X. I'm having trouble finding anything in 245/50/17; does anyone have a recommendation for some other size? Would a 245/45/17 tyre work well? Reason I'm looking at the size is that Yok A032R comes in this size and they've been recommended to me as a good competition tire for students who have exceeded the limits of street tires. Should I keep the same width for all 4 corners? Thanks.

 

What is the width of the rims that you have?

 

17 x 8.0.

 

OK. An 8 inch rim width is a bit narrow, so I suspect these are not wheels that you bought for track/autocross use on this car, but which you inherited from some other prior or alternative vehicle. Because this car is relatively heavy at around 3400lbs, if you are going to start tossing it around it might be worth considering going to a wider wheel before you drop some big money on tires and then find out you are not satisfied with the results. Especially if you could work a trade or trade up, etc.

You might seriously consider going to at least 8.5 inch and perhaps as much as 9.5 inch rim width. You can get 17 inch diameter tires from Hoosier and Kumho that will fit that offering. You will still get satisfactory side wall flex, but not too much and not too little either, and lots of contact patch for your cornering, acceleration and braking. It is a question of choice and preference of course, but I think that for performance driving the 8.0 inch all around is too skinny and you will quite possibly find yourself wanting to trade up to bigger width after dropping money on tires for the 8.0's.

The two other things to seriously consider to help your handling are to go for stiffer sways, and drop the car an inch to help lower the center of mass. These are simple and cost effective steps to really improve the response and stability of the car.

Good luck.

 

On the issue of stagger, if you go with the same size all around it will help dial out some of the programmed understeer on the car, which is a good thing for the track. The sways can also help in that regard. But lots of folks still run a stagger set up on the track and are happy. It depends on what you want the car to do and that makes you comfortable. A little bit of understeer is not necessarily a bad thing, if you have the responsiveness to transition it to oversteer when you want.

 

That's right, the 17"s I have are actually for my winter rubber. After my first event on the stock 19"s, there's just no way I can go on the rest of the season on 19"s and replacing tyres every month. This will actually just be a temporary measure until I pick up a cheaper track car sometime next year. (thinking along the lines of a 1st or 2nd gen RX7)

I'd like to keep all 4 corners the same size since that'll give me the opportunity to rotate my tyres and get a little bit more life out of them. My intention isn't to be competitive or even come close to the limits of the car just yet so I'm not planning to make any modifications to the suspension. Basically, I'm just looking to get through the year and be as cost-effective as I can until next season. 245/45/17 seems to be the closest size I can find for the Yokohama 032s but this would mean a loss of 1" in diameter. What's your opinion on running a setup like this? Thanks.

 

Sounds like you have, for your needs and situation, a very good approach, both cost effective and efficient.

The smaller overall diameter will have the net effect of "dropping " your car by a half inch, so that will help handling. Even size all around at 245 mm width is a good size and will help a touch with the understeer, and wear management too. If you just need to have some shoes for fun (and economically), it is indeed a good way to go. The 19's should not be run on the track, the sidewalls will be too stiff and short and the unsprung weight, and its placement far out on the wheel, will be undesireable as well. Those look great on the street, but that is where they should stay. How heavy are the 17's? Do you have a nice lightweight forged wheel that weighs around 17 pounds, or do you have heavy beater steel rims?

 

The 17"s aren't lightweight forged rims but they aren't heavy steel rims either. They're pretty run of the mill alloys: http://www.ubershane.com/images/balzzg35ex1.jpg

I just participated in a driver training trackday on the 19"s and they're in rough shape. Each track session was 20 minutes and I had to be very mindful of the tyres in the latter half of each session. I thought it would be better to learn the limits of street tyres first, but I think it would be foolish of me to run another event on them. An instructor strongly urged me to take the plunge too.

Thanks again for the advice.

 

Ran the Yokos for the first time this weekend. Going with the wider-over-stock front tire helped immensely at turn-in. Overall a great experience...the car felt more predictable at the limit and my times dropped consistently through the weekend. I ran with 35psi cold...no clue how to play around with pressures just yet...