ST tire eligibility requirements

[Fair!]

I just got schooled on corner carvers, *****ing about "wide open" ST tire eligibility rules. Here's an except of my shame:

--------------------from another board----------------------

Terry, ST tires have to be out by April 30, but you're right they only need to be out in one size.

Really? Wow... I didn't know this at all. Is this in a supplimental ST reg? Can you send a link to a PDF of this rule? Lemmie find my rule book... Well slap my ass and call me Sally! You are right, and it's right there on page 69 in the 2006 NationalsSolo rulebook! I cannot believe I missed that. It is noted as a change from the 2005 rules.

From the ST section:

14.3 Tires must meet the eligibility requirements of the Stock category (excluding 13.3F)...

From the Stock section:

13.3 B No tire models will be approved for competition during the rest of the year after April 30th of each calendar year.

13.3 F Each tire model must be sold in at least four rim diameters, with a total of at least 6 sizes.

Well, that is a relief, but if a tire manufacturer already has a "ringer" tire model out by April 30th in 1 size, they can keep introducing new sizes at any time. Still leaves a lot of unknowns out there, but not as bad as I thought. Good to know... thanks!

[Fair!]

Re: ST tire eligibility requirements

Also, in reference to STX (SeanT's class):

14.11 A. 4. Rim restriction: maximum width of 8", diameter/offset unrestricted. Tire restriction: max width 245mm. - so you can go up to a 245 tire, but on an 8" rim it's a bit squeezed...

14.11 A. 5. ... 2WD vehicles may use any LSD unit. - this means you can upgrade to a limited slip, and you should when funds allow this!

[McCall]

Re: ST tire eligibility requirements

Interesting info on the tire stuff. That really is a good relief (and may make me re-word my letter)

Also, in reference to STX (SeanT's class):

14.11 A. 4. Rim restriction: maximum width of 8", diameter/offset unrestricted. Tire restriction: max width 245mm. - so you can go up to a 245 tire, but on an 8" rim it's a bit squeezed...

Ah, all 16"-equipped f-bodies (3rd & 4th gens) and 17"-equipped Mustangs came with 245mm tires on 8" wide rims from the factory so I doubt the factories, which are notorious for undersizing tires on wheels (ie. RX, would squeeze too large of tires on factory wheels. Also, didn't C4s come with 255's on 8's? In other words, SeanT it's not a problem so go for it!!

[Redwood]

Re: ST tire eligibility requirements

Hmm, good to know for when I have to buy new tires! I don't know why I was thinking 225 was the max, but I was positive about 8". I wonder why Tommy didn't have wider tires. One issue is that Tommy's rims are 5mm more offset than mine, so they stick out more. There are not rubbing issues now, but I suspect 245 would rub up front on my current wheels.

[Fair!]

Re: ST tire eligibility requirements

Ah, all 16"-equipped f-bodies (3rd & 4th gens) and 17"-equipped Mustangs came with 245mm tires on 8" wide rims from the factory so I doubt the factories, which are notorious for undersizing tires on wheels (ie. RX, would squeeze too large of tires on factory wheels.

Well, I'd say it's the other way around. The factories build cars with fattie tires so that soccor moms don't rash the heck outta the wheels when they park too close to the curb. Fat tires on narrow rims is fairly common, and the 245/50/16 on hundreds of thousands of 16x8 F-body rims was a bit of a squeeze play. I'd much raher have a 16x8.5 or 16x9 wheel for the same 245mm tire.

We're running a 255 tire on a 9.5" wide wheel, but that isn't too crazy...

Also, didn't C4s come with 255's on 8's?

No, the narrowest factory C4 wheel with the 255mm tire was a 16x8.5", and the better handling Z51/Z51 1984-87 Corvettess had 16x9.5" wheels with that same 255/50/16 tire.

http://www.zr1netregistry.com/ZR1_suspension.htm <- check the listings

[Fair!]

Re: ST tire eligibility requirements

Hmm, good to know for when I have to buy new tires! I don't know why I was thinking 225 was the max, but I was positive about 8". I wonder why Tommy didn't have wider tires. One issue is that Tommy's rims are 5mm more offset than mine, so they stick out more. There are not rubbing issues now, but I suspect 245 would rub up front on my current wheels.

Have fender roller, will travel...

We can make 'em fit. Let's look at avilable ST tire sizes when it comes to that time and maybe there's an obvious fitment for your max width 17x8 race wheels. The limiting factor is whatever is made in a 225-245mm width for a 17" wheel... that isn't too tall... in a Yokohama or Falken 615... there will usually be but one choice.

[Redwood]

Re: ST tire eligibility requirements

Currently in the Yokohamas, my choices are:

225/45-17
235/40-17
245/40-17

Falken RT615s:

225/45-17
245/45-17

[McCall]

Re: ST tire eligibility requirements

245mm = 9.65"
275mm = 10.8"

9.56 10.8
---- = ----
8 9.5

86.4 vs. 90.82

So 245mm tires are 13.6% wider than 8" rims vs 275mm tires are only 9.18% wider than 9.5" rims*. I wouldn't have thunk that. I still don't buy the "soccer mom phenomena" though

*of course we know about manufactures tire size consistency (or lack there of)

Currently in the Yokohamas, my choices are:
235/40-17

245/40-17

I'd say one of those