Wheels and Tires

One of the chief challenges in the detail work to make this car handle well is the selection of wheels and tires. There are plenty of 13" tire sizes available if I look at racing compound tires, but there isn't much selection at the small end of the size range in street tires. I could get a set of standard street tires fairly easy if I look at 14" or 15" sizes, but high-performance rubber comes in much less variety.

After learning first-hand what a good set of tires would do for my Miata on the autocross course, I am very interested in good rubber. I'd love to use something like a Falken Azeni, Kumho Ecsta MX, or Hankook Rs2 for street use. These performance street tires though come in one size for a 14" wheel - the Miata's size - if they even go that small. That's great if you plan to run equal size front and rear tires in a car that has a 50/50 weight balance. On a car that has a 40/60 split though, the rears should have some extra width and ideally a bit larger outside diameter to avoid looking strange.

As I looked around at the tire sizes that are available, I was surprised to find that even the Lotus Elise uses 16 and 17 inch wheels. I expect that this adds some weight to an otherwise very lightweight vehicle. I would have figured that smaller wheels with smaller outer tire diameter would have been more in-line with the car's goals. Of course, the bling look probably helps to sell cars and the vehicle still weighs 20% less than anything else for sale.

The tire widths though were an interesting comparison point: 175 front and 225 rear. The front tires are actually narrower than the original Miata's tires. The difference between the fronts and rears is also about two inches in width. That's a large difference in width when you're shopping for street tires.

Now if I step back, reality dictates that I can't afford a new set of wheels unless I really keep the cost down. The best that I've found were some second-string high-performance tires that are available from a 195 up to a 225 width for 15 inch wheels. The upside is that these tires have been getting great reviews in the wet, so I should run well when it rains. Otherwise, I almost need to step up to large wheels and I have no interest in carrying the extra weight. Volk CE28N wheels would do the job great and allow me to use good tires, but they cost too much. SSR Comps would be my second choice for new wheels, but again they're too much. The plan then is to run a decent tire on my 15s and look for a decent compliment in 13s when I eventually go shopping for race slicks.

If I work things out, it would be nice to change the car's ride height for street and track use just by changing wheels. That way I don't need to adjust the car's setup to ru well with each set of tires. It may be a bit too much to ask though. I have found some Toyos in the sizes that I'd like, but theey'd be $200 per tire which is a bit steep. My current Azenis are only $280 for all four.