I am thinking about getting a set of 15x9 steelies for autocross and racing. I want to run Hankook Ventus RS3 225/45/15 tires at first. But I was wondering if a tire sized 205/50/15 would fit on a 9 inch rim? Or would a 205 be out of the question on a 9 inch rim for autocross purposes?

Also, what is the effects of a stretched tire on handling?

This is a picture I found online that claimed this is a 15x9 rim with a 205/50/15 tire. If thats what a 205 looks like on a 9 inch rim, then hell yeah I am going to buy some 15x9's.

How about you get those Work Equips insted!

I would think I 205 would work against you a little handling wise as you're not really putting all of that 9" width to the road. A 225 would probably be better.

Also, what class will you be running? Most have restrictions on tire width so that could work against you as well.

My car has been gutted and I am running coilovers with all the suspension components replaced with adjustable arms and all my emissions equipment have been removed so I think I will be put in the "prepared category". If I understand correctly then that means I can run up to a 12 inch wide rim? I didn't build my car for autocross, but I have recently decided to start doing it. So I will probably be put in a class way out of my league lol.

But you have a very good point, I definitely should find out for sure what class I will be running before I buy some rims and tires. I have been reading the SCCA Rulebook and damn it is long and confusing.

ScrapnSidwayz wrote:I am thinking about getting a set of 15x9 steelies for autocross and racing.

Ok, that's cool.

ScrapnSidwayz wrote:I want to run Hankook Ventus RS3 225/45/15 tires

You want to get skinnier tires to go racing? The whole point of getting wider wheels is to throw more rubber on them, and you are defying that principle.

ScrapnSidwayz wrote: Also, what is the effects of a stretched tire on handling?

A light stretch is good if you're running street tires. It'll stiffen up the sidewalls a little bit and give you much better feedback. Putting a 205mm tire on a 9 inch wide wheel is not a mild stretch, and it's just asking for a blowout and poor handling. Ask any drifter who's done it, it feels like you're on ice.

Go look around for a cheap set of 17x10's and throw some 265/40/17's on them. Much better than your original idea.

Naw, I don't want 17x10's, unless you can show me 17x10's for about the price of 15x9 steelies, because I haven't found any that I can afford. Otherwise I would have to buy some knockoff 17x10's and they would probably cost way more and weigh more then the steelies I want to get.

The reason I want to put a 225 on a 9 inch rim is because I have read lots of reviews about autocrosser's who said that a 225 feels a lot better on a 9 inch rim than it does on an 8 inch wide rim.

Also, the reason I asked if a 205 would be to much of a stretch is because that is the only size that the Falken Azenis rt-615k is offered
for a 15 inch rim. So I wasn't sure if that would be too much of a stretch and it sounds like it would be.

I wouldn't recommend those tires for track use. Autocross maybe but Falken Azenis don't hold up well to heat at all. And you won't be competitive running street tires in a prepared class. A 225 feels better on a 9 inch wheel because it's a mild stretch which like I said, stiffens up the sidewalls and improves feedback. I'm also gonna guess these are mostly Miata guys? Remember your car is bigger, heavier and more powerful than theirs.

Also, I don't know if you've ever researched 15x9 steelies, but they don't make them. You would have to get a custom set from Diamond Racing or something, and although they would probably be cheaper than knockoffs, they'll be of similar weight and won't be nearly as ideal for buying tires.

Yeah I know that I would have to special order them through Diamond Racing. Im just looking for a cheap alternative to tearing up my street tires. So I figured that with a set of 15x9's I could put on a grippier set of tires, and I could also run a shorter diameter tire and since Im running only a modded SOHC KA then that smaller diameter tire would give me a little quicker acceleration. Btw, Im still 4 lug so that kind of narrows down my rim choices.

I didn't build my car to be competitive in autocross, so I'm not trying to have the ultimate autocross setup, but there isn't anywhere else in Alabama to race. So I decided to do autocross for the time being for the experience and so I can go somewhere to drive the hell out of my car legally, until I get done with college and move somewhere else and have more money to play with.

Ok, I can see your point. I did a little more research for you and here's what you should do:

Run a 15x9 or 15x10 wheel with a 245/45/15 Hoosier R6 tire. This should be a touch smaller than your stock size (depending on whether you go with a 9 or 10 inch wide wheel). You don't want to go to small because your car should barely be able to get to 60mph in 2nd gear right now, and that's perfect for most autocross courses.

Now I don't know what your suspension setup is currently, but you're gonna want to run at least -3˚ camber all around, especially up front. Make sure all your bushings are in good shape and get everything as tight as you possibly can (strut tower bars/sway bars). You may not be that competitive (I have a friggin' V8 swapped 300zx and I got smoked) but your call will handle like a go-kart.

lol sweet... a v8 300zx sounds like it would be fun as hell to drive.

The suspension is set up pretty well already: I got coilovers, I replaced all the suspension arms with adjustable ones, I put in new front ball joints and new rear balll joints, front 3 point strut bar and rear 2 point strut bar, tension rod brace and then I got it professionally aligned.

Im running about -2 degrees camber and 1/16 toe out in the front and -1.5 degress negative camber and 1/16 toe in in the rear. This car is mainly my DD so I got the alignemnt set up kind of conservative to save on tire wear.

I have 205/50/16 Federal 595SS tires on the front right now and they aren't the greatest but the car holds the road extremely well. I think with wider, grippier tires, even though I would probably lose, it would be tons of fun to autox.

I will probably go with 15x9's though. I would love to buy those Hoosier R6's but I really can't imagine spending close to a grand on tires. The reason I picked out the Hankook Ventus RS3 is because they are pretty cheap, should have a pretty long life since they will mainly be used for autocross and maybe see a few street miles on some twisty roads, and should have quite a bit more grip than my current Federal's. I was also considering the Kumho Victoracer V700 in 225/50/15 because it's reasonably priced for a track tire, but Im not sure yet.

EDIT:
I just noticed that the 225/50/15 BFGoodrich g-Force R1 and the 225/45/15 Hankook Ventus Z214 are only a couple bucks more than the Victoracer, those tires should have quite a bit more grip than the Victoracer, what do you think would be the best? and do you have any idea how many miles I could expect out of a street tire like the Ventus RS3 compared to a race tire like the Ventus Z214?

Even though on the street you'll get a ton more miles out of a real street street tire, if you're pushing it hard you won't see as much of a difference. The RS3 has fairly large treadblocks so it won't be as bad as some other tires (the smaller the blocks, the more the tread gets chewed away), but you'll still probably experience some scalloping cause they're directional.

Out of all those, I would say the Z214 is definitely the best tire, but it's really too low profile. Your gearing will be really short with that. The R1's are great for autocross but once they get hot they start to fall off. They hold up pretty well to the Mustangs I used to work on though, so I'd recommended them.

Stock tire size is 195/60/15 and it says the the diameter is 24.2 inches and it says that the 225/45/15 Ventus RS3 is 23 inches. Does 1.2 inches make a huge difference? I was thinking that it would be good for a lil quicker acceleration, but I dont have much experience with different tire sizing and its effect on gearing.

What's the stock rev limit on a KA24E? I calculated your max speed (assuming a 6000rpm limit) to be ~53mph in second gear with the RS3, versus ~56 stock.

its at about 6500

car nut wrote:A light stretch is good if you're running street tires.

Savagely wrong. You will not find a single national competitor stretching tires. It is a total waste of contact patch and affects the tire adversely.

@OP: 214's are not race tires, they just r-comps. Race tires are bias ply which is only legal in Prepared/Modified classes. 214's are decent if you're doing track work but for auto-x they fall quite short of V710's or A6's. Honestly, grab a set of the widest 710's you can fit on your car and a gallon of Formula V. When you brick (ie: heat cycle out) the 710's, apply the Formula V and you should be fine for the year.

My God it was frustrating getting all the way to the bottom of this thread...

While I don't have the experience that flohtingPoint has, it doesn't take a genius to figure out that more contact patch=more grip so wtf are you guys thinking STRETCHING tires for race purposes?!?! This isn't hardparking with your hellaflush slammed fan boi crowd at the local 7-11. If you want to be fast around a track you need more tire not less.