The stock configuration for my car is ...

Front wheel/tire: 17 x 7.5 / 225 50 17
Rear wheel/tire: 17 x 8 / 235 50 17

I've searched the SCCA Solo II rule book to see if I can change the width and profile of the tire (within the Stock category), but cannot find anything that specifically mentions this.

My objective is to have four tires with the same width - either 235 or 245 if it will safely fit - and remain in B Stock. I suspect that this is not allowed, since it is not identical to manufacturer specs, but was hoping one of you guys could confirm.

If you're wondering why I would want to do this, I got the general idea from this ARTICLE, but can't afford to buy all the new wheels and tires described therein. Perhaps one day later on. Until then I thought this might be a good thing to try. Please let me know if I'm off base on this line of thinking.

Here's the specific part of the article I am using to make my assumptions.

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Here's how we found it: Look closely at the 350Z's suspension and there's only one obvious reason why it shouldn't be balanced--the front tires are smaller than the rears. This may seem a laughably naive question, but why? Two reasons: It looks tough and it makes the lawyers happy.

Screw the lawyers.

Nissan engineers left an insane amount of room for wide tires and, naturally, there's more room in the back than up front. This has led most people to continue this ludicrous staggered tire setup by trying to stuff the rear wheel wells with as much tire as possible. We went the opposite way, stuffing as much tire as possible under the front fenders and then using that size at both ends.
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Stock class for SCCA autocross allows *ANY* DOT-approved tire that fits the oem sized wheel that is not on the exclusion list.

stock on my car is 195/50/15 front and 205/50/15 rear. I run a 205/50/15 front and a 225/50/15 rear for competition purposes this year. Sometimes I run a 225/45/15 in the rear also.

 

As an aside to this thread...

Should I stop wasting time looking for the Falken Azeni RT 215? The new RT 615's are a bit on the expensive side. Any cheaper alternative ideas? Perhaps Kumho Ecsta MX? Any local place to buy these tires?

 

check out the hankook z212's

 

FWIW, I was up against Alann Gross last weekend at an "endurocross" autocross at SPC. We ran runs of 7 laps each, so it was a good chance to evaluate the consistency of tires.

Alann was in a '99 Miata with a new Bilstein PSS9 suspension (low and fairly stiff) and half-worn 195/60-14 Azenis. I was in my '96 Miata with Koni/Ground Control suspension (not as low, probably stiffer) and almost new 195/60-14 Hankook Z212's.

Average lap times for each of our fastest runs put Alann about 4/10 faster than me per 35-second lap. I'm sure part of that is that he just plain out-drove me, he usually does. Part of it could also be that he ran in the morning when it was cool, and I ran late in the afternoon when it was hot. He's also probably got more camber than I do as he just lowered his car some more and hasn't had it realigned yet.

Anyway... just thought I'd toss that out. The Hankook's were very consistent, never seemed to lose their grip. I'm still pretty sure they're on par with the Azenis. Like I said, Alann just out-drove me consistently.

Oh, one final excuse... it was a power-friendly course. Chad cleaned our clocks in his STi!

Results if anyone is interested:
http://sunridersmotorsports.com/srfi...ultsByTime.pdf

 

I've got the 615's and love them. Price isn't really any different than the MX's. Even in my size (275/40/17) there's only about a $10 difference in price. If $40 is going to break the bank, you've picked the wrong hobby.

 

Thanks for the answer to my original question, Jesse.

I researched these tires more, decided to buy them, then met with nothing but disappointment. Nobody can get their hands on them for X amount of time. One place said 2 or 3 weeks. Another said 2 or 3 months. I appreciate the honesty from the latter. I'm betting if they could keep these things in stock, Falken and Kumho would start being afraid.

You're not the first person to accuse me of being chincy by a long shot. Count the pennies and the dollars will take care of themselves. Add shipping and mounting for each tire and this is about what you get for four tires.

Falken RT615: $159 ... ~$756 (vulcantire.com)
Kumho MX: $139 ... ~$676 (tirerack.com)
Hankook Z212: $106 ... ~$544 (edgeracing.com)

 

I'd say the relative prices are pretty close to reflective of the ultimate performance of the tires. I say that having driving on the RT615's and the MX's. The hankook's are probably better than their price, but still slower than either the Falken or the Kumho.

If you're at all interested in being competative, there are far better places to save your money than on tires.

 

Rosko, Don't worry about the competitiveness of a street tire when you're running in stock class. It's pretty useless. It's sorta like trying to figure out the best laptop when you're trying to run NASA. You're bringing a knife to the gunfight anyway, so just bring the knife you like best. When you get serious, you'll find the best gun, but that comes later.