13" Race Tires

racer_tim

racer_tim

Moderator
Staff member
I think SCCA needs to do the same thing, with Production and GTL rules. I know the trend is to larger, but at what point is enough, enough? We've seen all these STUPID cars on 20" and 22" rims, and they look like old rims from a Wagon Train that crossed the Oklahoma Territory for California.

We all know that the 13" slicks are only made by Hoosier, Avon, and that Goodyear is considering making the 20x9.5x13 slick again. 13" rims are also getting hard to find, so going with 15", 16" 17" or 18" rims is coming down the road, so do we want to hold out and be dinosaurs, or do we need to make a natural transition so we're not left out in the cold.

http://www.motorsport.com/f1/news/miche ... wheel-size
 
I'd be in favor of open diameter rule. Spec line has width only.

Always wondered why anyone who could run 13s would go to 17s.

If you're worried about too much change, spec the width and (one) diameter, then make a rule that says diameter +- 2".

Been thinking about writing the CRB for awhile. I hear they love hearing from me.
 
The only problem that I see is that you are raising the center of gravity. With out the ability of moving the suspension pickup points it messes up the roll centers. G
 
Don't forget about unsprung weight increase and gearing changes. How about 10#s per corner for a 2" dia. change!?
 
Don't overlook rotational mass (flywheel); Tires and wheels have to be accelerated and decelerated. HP and brakes.

13" tires give up some contact patch, but have way less rotational mass.

RJS
 
There is no shortage of either wheels or tires in 13".

This is the kind of thing that almost always comes around and bites you in the a** with unintended consequences.

It's not broken, let's not fix it.

Kyle
 
There are 800+ Spec Racers that are on 13" tires. Somehow I don't see them going to a different tire size.

I know that those tires are less than optimal for little GT and F/H Prod but rather than go to 15" or larger wheels I would think that we could use the same tires as Spec Racers.

This only would apply if all other options suddenly disappear.
 
Also keep in mind that some cars physically can not run larger rims (15, 16, etc.)... Why would SCCA impose a rule that would force even more cars to park themselves and/or go to another sanctioning body?

Another food for thought... some cars that ran 15's for years have elected to run 13's this season. RJ hit the nail on the head.

As long as there is a demand, the market will fill it. I'm with Kyle on this one... I don't think we have to worry about 13" rims going away any time soon. Stock rims, perhaps, but after market ones should be around for years to come.
 
Not interested in running anything bigger than 13" at this point. With my low HP car trying to get 15" wheels and tires moving and stopped takes alot of energy.

I can run 15", but with a penalty.

Plus, it looks like F1 is doing ok with 13" wheels.
 
I agree. No need to run bigger than 13" wheels. The Spec racer tires are approx. 22" tall. The size of a 205/60x13 roughly. That is about the biggest that I can see using.

I test fit some 15's and there is no shortage of issues. They could be overcome but it would require reworking a bunch of stuff. Plus the larger diameter causes all of the other issues that have been mentioned.
 
They tried it, but.....

Formula One teams do no want to change wheel diameters from 13 inches to 18, despite current tyre supplier Pirelli and rivals Michelin showing interest in such a move.
Click to expand...
 
Less important than diameter is width. I'm fine with 13" wheels, but with many cantilever options going away, it's pretty tough to squeeze a 225 series straight sidewall radial on a 6" rim without giving something up in the process.

Further, I am surprised no one commented on he May Fastrack that gave anyone running American Racer (already a 7" unrestricted allowance) an 8 inch wheel, regardless of class or car. 8 inch!

-M
 
Matt Brannon":2e93q4bl said:
Less important than diameter is width. I'm fine with 13" wheels, but with many cantilever options going away, it's pretty tough to squeeze a 225 series straight sidewall radial on a 6" rim without giving something up in the process.

Further, I am surprised no one commented on he May Fastrack that gave anyone running American Racer (already a 7" unrestricted allowance) an 8 inch wheel, regardless of class or car. 8 inch!

-M
Click to expand...
Matt,
Those that have run the AR tires have shown to be well off the pace, so running an 8" rim on them still has them at a disadvantage to a Hoosier/Goodyear on a 7" rim.
 
Matt Brannon":3mnplzup said:
Further, I am surprised no one commented on he May Fastrack that gave anyone running American Racer (already a 7" unrestricted allowance) an 8 inch wheel, regardless of class or car. 8 inch!
Click to expand...
Feel free to try them out, and report back on how that worked out for you. :wink: Still pisses me off that the CRB ever chose to allow those stupid American Racer rules....

The only way the wheel width thing gets standardized is to go to a box rule, but there's still enough people in Prod-land who will only ever see cantilevers "pried from my cold dead hands", that you'd have to have a box that's wide enough to encapture those things too. So in the 15" diameter for example, you're talking about a 10-10.5" width allowance. Who likes the sound of 15x9" wheels holding a 10" wide Hoosier radial? They'll be $400+ a piece and crush track records, but also perfectly legal. If Goodyear and Hoosier finally said "we're completely done ever producing these cantilevers", that would actually make this a lot easier.
 
Matt Brannon":l9gveas4 said:
Less important than diameter is width. I'm fine with 13" wheels, but with many cantilever options going away, it's pretty tough to squeeze a 225 series straight sidewall radial on a 6" rim without giving something up in the process.

Further, I am surprised no one commented on he May Fastrack that gave anyone running American Racer (already a 7" unrestricted allowance) an 8 inch wheel, regardless of class or car. 8 inch!

-M
Click to expand...

Where are finding a 225-13" radial slick? I would interested in them if I could find a competitive one in that size. Hoosier offers a 190 and 215, both of which state an acceptable rim width of 6-7". I guess the 215 works OK on a 6" wheel since the Honda that has been spanking everyone for years is using that setup. I wonder if the Honda would get quicker with another inch of wheel?

The AR thing in Fastrack was not a new allowance, it was a correction to the rule the CRB created which only allowed one size wheel, our rules have always stated a max width not a single width, now it is in line with the others. Not that we should have such an allowance no matter how much of a turd the AR tire may be.
 
Jason,
I think my Honda would benefit greatly from a 7" wheel. If there was a radial slick available in a 225 then it would help us even more.
I feel that the Hondas are on a little 13x6 wheel as a way of limiting a car that some feel is already too fast in HP.
 
The wheel sizes have needed attention for a number of years.

The 2450lb S2000 gets 17x8.5 wheels. The 2675lb 328 gets 17x8.5 wheels. I'm told it's because those widths were offered stock on the car.

If that's the only criteria, then why doesn't the miata get 6" wheels?

The reason is, the criteria changes with the blowing of the wind.
 
blamkin86":118ihknm said:
The wheel sizes have needed attention for a number of years.

The 2450lb S2000 gets 17x8.5 wheels. The 2675lb 328 gets 17x8.5 wheels. I'm told it's because those widths were offered stock on the car.

If that's the only criteria, then why doesn't the miata get 6" wheels?

The reason is, the criteria changes with the blowing of the wind.
Click to expand...

To further fuel the consistent inconsistency... The base S2K never came with an 8.5", that was the limited production CR edition which is not in EP. I was always told the odd 8.5" wheels size came from IT crossovers. Guess we will never know how we got here. :|
 
You must log in or register to reply here.
Back
Top