Wheels Size and AutoX
 

This may of been asked and it may of been asked 100x, but in my basic searching I cannot find much info.

I was looking at getting 18" wheels. I did some AutoX and it is very easy to understeer with stock tires. Yes, I know it is the driver too. A lot of it is me pushing too hard and not driving well, but the stock tires don't help. I have only had understeer issues at the autox course(s) so far.

Would upgrading to 18x8/8.5/9/9.5 be a good upgrade, or should I stick to 17" wheels with new rubber, or 17" and get wider wheels?

I planned on getting 18x9.5 in the rear and 18x8 in the front to fill in the wheel gap and get better traction, but I don't want to wait to buy my wheels and the set I was looking at was more than I can spend right now.

I am making absolutely sure that the wheels weigh less than the 17s I have. I have a series.blue and from my research the wheels are 19-21lbs each. I am looking at the Motegi MR131 Traklites. They only come in 18x8. The price is nice, and the weight is even better! I don't necessarily like the wheels, but the price + weight are nice, so I figured I would go with that.

Is there any reason I shouldn't go with 18"? Is 17" > 18"? And lastly, should I go with something that is 18x9.5" in the rear, or will 18x8 (all around) do the trick?

Thanks in advance for the help, and sorry if this has been asked before. I couldn't find much.

your post is too long. and your search fu is weak.

Go with wheels as light as you can, I would stick with 17 inch, run 245 rubber thats the basic recipe/starting point for autoX

edit: just glaced at your post and saw you are thinking about staggered, that will give you a lot of under-steer dont do it lol!

What's your alignment look like? You're going to want more negative camber in the front if you're at OEM alignment specs.

Don't stagger your wheel sizes. If you want to stay in SCCA C Street, you have to stay 17x7, but you can go lighter. Most autocross folks are running 17x7 or 17x9 depending on which class they're in.

18" will make your ride harsher, may likely increase unsprung mass, and slightly improve steering response. 17" is better for ride quality and easier/cheaper to keep the weight down. Tires are also significantly cheaper in 17.

Changing tires won't fix your handling problems, at best it will mask the problems by adding enough grip that you're not driving at the limit of the grip available so your times improve and everything feels great, until someone steps in behind the wheel actually drives it at the limit, or you step up your game and the problems return. At worst it could actually exacerbate the problem, especially as the tires wear in an imbalanced fashion.

What classing and ruleset are you building to? This can be extremely restrictive to your wheel and tire choice and buying what you want without looking will put you into a class where you will be noncompetitive unless you spend $5k, $10k, $25k on modifications adding more lightness, power, and grip.

If you're just doing it for fun, awesome! Do what you want.

My 2 cents are, again, tires won't solve anything. From a stock setup the thing most lacking is camber on the front end. Adding camber up front will add grip on the front tires when turning reducing understeer, camber bolts will put you in the -1 to -1.5 degree range, a big improvement over stock which is usually less than -0.5 and perfectly streetable. With bolts and camber plates you can run up over -3.0 degrees which felt great for me, what you do will depend on the class you want to run in.

The two most common classes for autocrossing an 86 are SCCA CS and STX. With CS you are limited to OE size wheels and OE crash bolts, STX opens up a lot of possibilities but you're looking at around $5k to get in the ballpark in terms of tire, suspension and power and some real talent to get it dialed in.

@strat61caster has hit all the big points. I'm just going to piggyback on it.

The stock tires DO help you learn! You'll learn to control the car better at the limit when the limits are so much lower on the stock tires vs sticky ones. With stickier tires, the limit is higher, and they will be less forgiving when you eventually exceed that limit. I'm a believer of the whole "the easier to learn, the faster you learn" philosophy.

If you get a staggered wheel/tire setup, you'll likely just get more understeer. The guys in in STX usually run a square setup - typically 17x9 with 245/40R17. This will offer loads of traction when combined with some more camber adjustment. I'd play around on the stock setup or a CS-prep if you're still learning. I compete in C-Street with a second set of 17x7 wheels with my autocross-dedicated tires.

I haven't seen anyone competitive in our region in CS or STX classes with 18" wheels. Tires will probably be more expensive too. It's not worth going to 18" wheels unless you want the look or if you are going to run something wider than a 255/40R17, but you may want more power to make up for increased rotating mass.

I do about 4 or 5 events on stock wheels and tires before I started adding the OEM camber bolts, front sway bar, and got a dedicated set of used wheels and tires. A year later, I got Koni dampers.

If I wanted to go with 9" width, does that fit the front? I thought the widest you could get up front was 8"? That was why I was looking at staggering, not necessarily because I wanted to.

I would be Auto crossing just for fun this season as I am new to it all. Learning and enjoying mainly this season.

I was looking at doing little mods here and there. Tires/wheels, springs, sway bars etc, and brakes.

I wanted to start with tires/wheels.

Thanks all. Now to start the hunt all over. I am mostly a car newb and I was set on 18". I will look at 17" now, or maybe just buy new tires and stick with the stock rims. I do like them, being that it is the series.blue and not the other version.

Add the $20 OEM camber bolts and an alignment then autocross on your stock tires for this season. You can decide if you want to stay in C Street or move up to STX. You can play around with your tire pressure as well if you find that the stock tires are rolling over.

Agreed, get some camber in the front, and get a bit more seat time.


17x9 does fit correctly on stock suspension, pending offset and tire size. I ran 17x9 +42 with 245 tires on stock suspension for a season. I was stock alignment tho. The car was much better with just the tires.

I wouldn't suggest spending the money on another set of 17x7 wheels unless you make up your mind that you will keep yoru car as a CS car, personally, it was never an option for me so I went traight to a 17x9.

I want to go to 17x9, but maybe I will just upgrade the tires since I need to anyways for daily driving. I'll wait till I am a bit better at Autox before I buy wheels.

Does that sound like a good start? Camber bolts/alignment and new tread.

Maybe I will just buy some better brake pads for now instead of the wheels.
I also have not upgrade my fluids. I really need to do that!

Thanks again for all the help so far.

Getting into autox the cheapest upgrade that worked well for me was brake fluid swap. But I didn't do a front camber bolt. Having experienced 1.5 degrees of front camber I can now honestly say that is the best bang for your buck.

If you do that and new rubber on stock wheels; you can stay in CS and put up some competitive times. I did one year this way, then just tires the next year (17x8 though), and now for my third year I'm taking all that money I saved and doing a more complete STX package for the car. Early on, I wasted all of my money on seat time, and I continue to prioritize that.

Just my 2 cents in the bucket...

I'm not a believer in autocrossing on crappy stock tires to learn something, the car behaves very differently on them than any real performance tire. Sam Strano (many time national champ) said the same thing when he was still on here. Tires can hide bad driving, but you also can't progress very far on the stock tires.

I would get tires first and autocross in CS (basically stock) class to start with.

The stock brake pads and fluids are fine.

The stock pads are pretty capable for autox. It was the last thing I did besides exhaust. I'd keep the stock tires on - I still have them for daily driving. But you do you.

I am going to upgrade the tires. I planned to anyways. I have been fairly mean to my stocks knowing they aren't great. I have just under 30k on them.

I am not sure if my driving is good or bad, but I definitely had understeer a lot on the course they made up. I do canyon runs often and don't have issues with cornering there, but I also don't push as hard considering blind corners and possible civilians/cars.

I dropped 7 seconds by my second run. I was initially just driving, not worrying about the apex etc. I was also playing with the stock tires sliding a bit.

I have a full 2.5" exhaust, short throw shifter, lightweight pullies (I know), and the OFT.

No offense OP, but if your skill/knowledge level is "are 17s better than 18s?" you are exactly the kind of person who needs to spend some time autocrossing the car on stock tires.

Grippy tires will mask your mistakes. They will allow you to develop bad habits that "feel" fast but are actually slow. Stock tires will punish you for every mistake; the understeer is trying to tell you something. You can either try to learn from that something and become a fast driver, or you can bolt on grip and pretend you're a fast driver. I won't judge you either way as long as you're honest about it.

Very little of your canyon experience will translate to a 10/10ths autocross environment.

If you are dropping 7 seconds per run on the stock tires, you have lots of room for progress.

I meant to say, I am pretty much the best driver under the sun (when it's out). Do you see the dilemma there? I don't want to say I am a great driver. I think I do fine. What I am not, is a mechanic, or anything other than an enthusiast who is learning as I go, and with anything on the internet, there is a lot of conflicting data. Which is where forums come in, or should I say community. I trust that someone here has way more knowledge than me, and some can wade through the bs and take me with them.

I am definitely learning as far as autox goes, there is no doubt about it. I have done a total of probably 15 laps so far. I was kind of band wagoning it. Lots of people go the 18x9.5 route, and I figured as long as I shed the weight the bigger size would at least balance out, but again conflicting data found have I!

Regardless of opinion (thank you btw) I need to replace the tires because I hate them, lol. They don't feel good, and they take away from the car, even if I do suck at driving. Primacy's should not of been on the car from the start unless they wanted to show how drifty it can be. They do OK, but I don't have enough trust in them.

Again, thank you (all), even if I don't like your opinion, haha.

I didn't read the whole thread. OP, for autocross, 17>18 for unsprung mass. Wider is better. And you need camber(like -3 front-2 rear). 18s look better so if these will be your dd wheels then get 18 cuz looking good 100% if the time > being .05 seconds faster a few times a year. Don't stagger your setup

18x9.5 for autox in this car? You must make a lot of power.

Since you have some modifications already, I would look into running STX if you want to be somewhat competitive in autocross. Get some 17x9 wheels.