Tire/Wheel size for AutoX?

[Toecutter]

I will be getting a start in AutoX soon (STS), so for the moment I will be running my street tires which are 205/50-16 Khumo Ecsta SPT's on Rota Track R 16 x 7" wheels.

However, I was thinking about using the stock alloys that came with the car for AutoX. I have been reading that a shorter tire might help in several of the following ways:

* Lowers car
* Stiffer sidewall
* Changes final drive ratio

My question is twofold. Is it worth downsizing on the stock rim, or should I stick with my 16 x 7" rims?
If downsizing on the stock rim is a good idea, then what would be a good choice for tire size?

Oh yeah, one more question. Would there be a benefit to using 15 x 7" wheels?

[only1db]

a lot of people have been going with 205/50's

but the stock alloy is quite heavy...i think its up near 23lbs+...but if you get lightweight 16's it would be better less weight and then down size on the 16...

[SWortham]

Falken Azenis RT-615's in 215/45-16 would be good for your 16's. The gearing in the Elantra is such that I never had to shift to 3rd in the autocross events I've been to. And so I never made full use of 2nd gear. So yeah, a smaller rolling diameter would certainly help.

[only1db]

does 215 put you in to a different class?

[SWortham]

Nope, STS allows up to 7.5" wide wheels and 225mm tires.

[Toecutter]

Thanks for all the good info guys! I really appreciate it.

I had no idea that the stock wheels were so damn heavy. My 16" Rotas at 16 lbs isn't too shabby for cast wheels. If I like doing this, then maybe I'll pony up for another set before the start of next season. I like my Rotas for the street, and want to have a set dedicated for racing only.

What are you running on the STI Steve?

[silet]

The stock alloys are heavy, but they are around 19 lbs and weight the same as the steels. 205/50/15 would give you a lower diameter and that benefit is greater than getting 15 lb wheel.

[LateAPXR]

I would stick with your 16's for the advantage of less sidewall to roll over turning turning. I'm stuck (because of $) running my stock alloy's and all seasons and let me tell you...they SUCK.

You'll have crisper turn in and sharper cornering with the larger wheels. Especially if they are lighter too. Stock wheel/tire combo is around 40lbs per corner.

ANYthing is better then stock in your situation.

But yeah..15's and some NICE rubber on them is a great combination. Oiml8 on EC runs the Falken Azenis RT-215's (205/50/R15) on a lightweight 15in wheel and it's a great combination for him.

The newer RT-615's are a GREAT tire. Get them or don't buy anything IMHO.

[SWortham]

What are you running on the STI Steve?
It's completely stock right now. The tires are 225/45-17 Bridgestone RE050's.

EDIT -- Oops, make that RE070's.

[Toecutter]

Those Azenis RT-615's look pretty good for Auto-X, and the price ain't bad either. As long as the venue isn't too far away (home venue is about 37 miles each way for me), I would see no problem driving on them to and from the event. Now I just have to decide 15 x 6.5" stock, 15 x 7" lightweight or 16 x 7" lightweight. I guess I'll have to mull that over a bit.

[CTele02]

Get lightweight 15x7 rims... then fit them 225/50/15 tires... and you're set. May have to roll fenders a tad if you have a severe drop in suspension.

I personally have 15x7 rota slipstreams (13lbs) and 205/55/15 BFG G-force sports V-rated, you require a 7inch rim to have 225 wide tires (which one day i hope to upgrade to in the same BFG tread)

[Toecutter]

Thanks for the suggestion. No drop yet, maybe 1" in the future with Eibachs.

[only1db]

the problem is going to be with the offset ...if you have 42 mm offset on the rim you should be ok...but might rub on the inside on the strut itself...especially if your going to put any negative camber on...which is almost as must for autocrossing...the only way to get around the bulky struts is to get coils...like the H&R, TEIN, or the Ksports. they have a smaller diamter and no bulky spring seat...being that they are thinner you can run a bigger tire....

i have konig holes with a 45 offset...i want to run 225's i should have no issues...if anything you can get different wheel spacers custom made for different mm. < just a thought.

[Toecutter]

I'm not going to get coilovers. They are just too bloody expensive. So would you say that the widest I could go with the stock struts and no fender rolling is 215? This would be with a 45mm offset.

[XDGT03]

You say that now but once you got the racing bug you'll be dumping big cash fast. lol

I'm oiml8 on EC

if you don't want to spend the cash for coilovers then your next best bet is the tib struts and h&r springs. I would not go with the eibachs of you intend to autox. You will probably have a tough time being competetive with them.

Tires is a big issue for me right now. The Rt-615's have been the best option for autox. However the BFG KD's are showing signs of being a good option too. However, I have only seen them run on a RWD car and the heat generated on the front tires of a FWD car can maybe be too much for them. SO, I am seriously looking at the Kumho V-710. Plus you can go even wider. With my coilovers I can get away with this. This would put me and you into FSP instead of STS and therefore not much competition but you can get contingency from Kumho that can save you up to $300 off the purchase of a new set. In the Detroit region the fastest STS cars are running about the same times as the fastest FSP cars.

For more info about tire tread temps and setup thoughts check out
http://www.elantraclub.com/forum/index.php?showforum=53

[Toecutter]

I've seen your posts over on EC XDGT03, thanks for posting here too. The contingency looks interesting, but I really want to avoid bumping into FSP at this point. Also, thanks for the link.

[Toecutter]

You say that now but once you got the racing bug you'll be dumping big cash fast. lol

Yo are so right! I've been bitten bad. I competed in my first autocross event. This was a two day affair with two heats each day consisting of 3 runs each. So I raced a total of 12 times. It was such a blast and I can't wait for the next event. I ran in STS, consistently got better with each run, and didn't come in last place :). However, it would seem that the Kumho SPTs aren't quite up to the task and neither is the suspension.

My new question is. If I go with Ksport coilovers, what is the widest tire that I can run? I will buy dedicated race wheels, so I can specify the offset. Also, what is involved in rolling the lip inside the fender well. Is this something that I can take on, or should it go to a body shop (special tools)?

[Toecutter]

I think that it's fair to say that nobody knows the answer to may previous question, but that's OK. I'll just have to measure for myself once I get the KSport's installed.

I have a more important question. Does anybody know what the camber gain of the Elantra?

[Captain Fuzzy]

i have 215/60R15s on stock steel rims....too big of a side wall?

[Toecutter]

I think that 5.07" sidewall is way too much for autoX, but I am no expert. Pehaps someone else can chime in on this.

[BobMs_wht2k2]

Not only too tall of a sidewall but it will dramatically affect your gearing. By going up that extra 5% in tire height you've affected your actual final drie ratio 5% in the WRONG direction. Add in the fact that no 60-series tire is going to be anything but a all-season and you'll never have enough grip to get close to the competition.

[Captain Fuzzy]

thanx...i didnt buy the tires my dad did when they got it for my graduation present.( they are LeMans Champion HR with an H rating )

so my car is actually working harder than it should...killin mpg?
im think im gonna go wtih a 45 or 50 series next when i get new wheels

as for grip...ive never gotten any slippage from high speed turning....i dont wanna try to hard and roll it. the car is fully stock for now but im gonna gettin parts this winter when we get our new house with a garage.

[BobMs_wht2k2]

Also keep in mind you're physically going at least 5% faster than what your speedo shows.

[Captain Fuzzy]

hmm..didnt think about that.
will these tires wearout part of my car faster as well....i thought about it last night and wasnt sure

[BobMs_wht2k2]

not really.

[Captain Fuzzy]

ok. thanx alot