Racing series wheel and tire sizes

[a_ahmed]

I know some of you guys have interesting info out there. Like biggie he mentioned JGTC tire sizes in a thread.

I was wondering what the variety of wheel/tire sizes are out there in different racing series, be it JGTC, BTCC, SuperGT, DTM, old/new historical, whatever.

It'd be interesting to know... if you have knowledge on the subject post away different cars/their size specs/etc...

Was searching for some DTM cars and I could not for the love of God find the wheel/tire specs..... Was trying to find specific jgtc/supergt sizes as well and i could not. Was trying to see what slicks they were using and all that.

[Matt93SE]

You're gonna spend a lot of time digging through each sanctioning body's rules and specs.

Also go to Hoosier's website. They have a lot of Rolex GT and Koni spec tires listed on their site in the road racing tires section.

[nismofly]

Yeah your best bet is to check the rules for the series you're trying to find, because not only will the series have different tire rules but each car within the series will have maximum tire sizes, or the series will mandate sizes based on a cars weight.

For example world challenge TC every car runs 235/40/17 r888's on 17x8 wheels...GT run anywhere from 275/35/18 to 335/30/18, each car has size requirements. Whats now continental sports car challenge youll see everything from the 225/15s on minis to 275 and 285/18s on mustangs and other larger cars. The stagger is also controlled.

Series rules are fairly easy to find on the respective websites.

[Matt93SE]

Does TC mandate a 17x8 or is that the maximum? For SCCA STU (which allows TC cars directly), you're allowed to run anything up to a 17x8, and any tire you can fit on it. :shrug:

[nismofly]

They mandate a 235/40/17, and maximum wheel size is 17x8, and everybody runs that because 235s are perfect on 8s and most of the wheels these teams run only come with proper bolt patterns and offsets in 17x8 or wider.

For example rpf1s you can only get 17x7 with 4x100 and +43, 17x7.5 proper bolt patterns but +48, but 17x8 comes in 5x100 and 5x114.3, and +35 offset.

The any tire you can fit on it deal probably is to allow club racers to buy used tires, anywhere you look in club racing they rarely set exact widths for wheels/tires, just maximums. Although you can get so many very lightly used 235/40 r888's from WC teams that its probably what a lot of people end up running anyway.

[McCoy]

Ahmed, just buy these (http://www.nasaforums.com/viewtopic.php?f=34&t=33049)and be done with it ;)

[BeerBringer]

S2000 (WTCC, BTCC, STCC etc.) wheel and tire spec:
Maximum 17x9" wheels. Wheels can't be lighter than 9 kg each.
Inflated at minimum 2 bar the wheels must fit in a box 610 mm high and 250 mm wide.

Wheels must be made from cast aluminium and be 1-piece.
(I guess to keep cost down)

http://www.stcc.se/fileadmin/user_upload/PDF/STCC/STCC_2010/STCC_FIA_Art.263_2010.pdf

Thats why no european wheel manufacturer makes awsome lightweight wheels anymore...there is no market for racing wheels as there used to be.

Compomotive, Speedline, OZ, BBS used to make super cool wheels. Now they all suck.

[a_ahmed]

^That's pretty gay rules, thanks for the find though.

I like japan's idea of slashing seconds off lap times through less restrictions than gay regulations to make the world a happy happy greener place because the UN wants to tax the world or some such thing like that. Boo. Bring on the quad turbo v12s in formula 1 roooaaar.

Mccoy: roflcopter *giggle* oooh do want

[Matt93SE]

The issue is more to keep costs down so the average Joe can race, vs. the "hexa-dodecahedron-triple-threaded-magnesium-Gracer-spec" wheels that you're thinking you see in racing.
That's all fine and dandy once you get to pro racing or are builind a Ferrari or Viper. the rest of the amateur racing world goes with cast/forged aluminum wheels that do the job such as 5Zigen, Enkei, and SSR.

[nismofly]

Yeah but Ive never quite understood it for BTCC/WTCC where they allow crazy suspension and engine mods, full dogboxes...hell said "cheap" wheels are single nut so they're not even that cheap.

[BeerBringer]

S2000 is still realy expensive. But no where near as expensive as Super Touring was.
When a series gets so expensive that even the work teams cant affort to participate anymore you have to do something. Without teams there will be no racing...

Same thing is happening in WRC. There are only two factory teams left...
This is the last year they run WRC cars. Next year only cars following the S2000 (different from the racing S2000) rule book will be allowed.

But I agree that strict rules makes racing kind of booring.
I love Group A and Supertouring cars because they used standard cars and went crazy on them.

[Jonty]

Yeah but Ive never quite understood it for BTCC/WTCC where they allow crazy suspension and engine mods, full dogboxes...hell said "cheap" wheels are single nut so they're not even that cheap.

It's also cos the wheel isn't an obvious performance differentiator, so it doesn't add to the spectacle for fans- having an engine and transmission that can get the car to 100mph in 9 seconds they will see, but the action of a reduced rotating and unsprung mass is a bit harder to witness.

To me it's good regs, and even better is the regular supply of 235/40/17 dunlop slicks that I can pick up for about £100 a set which go straight onto my 9x17 GTR rims :D

[Matt93SE]

We do the same with 235/40 and 235/45/17 with the MX5 cup, Solstice GXP, and SpecVWDiesel guys.. Unofrtunately they all run R888s instead of something cool.

I've been buying take-off R888s for about $35 each for the last year or so. shaved + 1-heat cycle ones go for about $70 each. still WAY cheaper than $200 each for a new R888.

[Def]

Hey Matt, any good 255/40-17 R-comp deals from other series like that? Although a 235/40-17 R888 might not be too much narrower than a 255/40-17 "wide" street tire like an NT-05 or Star Spec.

[Matt93SE]

I dunno. I just called them up and told them anything in a 235-245 35-45 and they said they had a bunch of 235/40s and 245/45s..

I get mine from jbracingtires.net
I actually need to call them tomorrow and get another couple sets of tires. I'll ask them what they've got while I have them on the phone.

[stewiefied]

Nice, that's like 30 miles from me. Going to give them a call tomorrow.

[Def]

What's your take on the speed difference between some moderately heat cycled R888's and something like an NT-05 or Dunlop Starspec?

[Matt93SE]

I was hoping someone else could answer that as well.
I'm trying to decide if I want to throw a set on some 16x7.5 (Z32NA) wheels for DE days and maybe rain tires and keep the 17x8s for DOT-Rs.

[Matt93SE]

Just talked to John Berget, and he said he'll be getting in some 225/45/17 Hoosiers and 710s in the next few days.

Def, what tire are you looking for? He says he doesn't usually get the 255 since they're less common, but he gets tons of Hoosiers and R888s in 245/45/17 since it's a popular size for the Mustang guys and whatnot.

And yeah, a Hoosier 245 will be as wide or slightly wider than a 255 street tire. He said they run about a size wider than you'd expect.

Based on my tire temps recently and that info, I think I'm going to try a set of 225/45 Hoosier R6 and maybe some 710s.

[turtl631]

Only issue with 245/45 is that it's a pretty tall tire for these cars. But 255/40, while a nice size, just isn't really used in any racing commonly.

[Matt93SE]

BFG R1 has a 255.40.17 listed, as well as Kumho V700 Victoracers.

for a lot of people, they want the extra gearing of a 245/45/17. it's only about 1/2" taller than a 255/40, so it's not that bad really. I've run it on a few different tires in the past and was fine with the size.

[FlatOut]

I didn't read any of the post except for the original post. I run 275/40-17 hoosier R6's on a 17x8 rim and i am very happy with the grip