Hello all.
I am starting this thread to discuss my plans for setting up my AP1 for SCCA C Street autocross. This will be my first year running the car in C Street and I wanted to post my plans for wheel and tire set up. I have found it hard to find the best options for wheels and tires so I hope this helps others and maybe someone more experienced will be able to inform my selection further. There is a Guide to C Street thread that I found which was a helpful start.

First some Class rules.

• C Street must run wheels that are withing 1 inch of the stock diameter (AP1 stock diameter is 16''). So a C Street AP1 can run 15, 16, or 17.
• Wheel width must remain unchanged. (Stock AP1 front wheel width is 6.5 and rear is 7.5)
• C Street wheel offset must be within +/-7mm from the stock offset. (The AP1 stock front offset is +55 and rear is +65). For grip it is best to run lower offset, pushing the wheels outward. Some might say you want to shorten the track width to make it easier to navigate the car around comes but I believe the real weakness in C Street is grip and not car width so I decided to increase the track width. So I will be running as close to +48 front and +58 rear as I can find wheels for.

Wheel selection
Decreasing unsprung mass is a benefit to car handling so lighter wheels from stock is what you should be looking for. So my first and only choice at the moment for wheel are the Work Seeker and Muenster wheels in 16'' diameter. I am particularly a fan of the Work Seeker FX wheels. They allow you to customize your offset because of their two piece design so I can achieve my optimal offsets above. I found this wheel in that Guide to C Street I spoke of earlier.

Wheel questions

1. Does anyone know the weight of 16x6.5 and 16x7.5 work seeker FX Wheels?
2. Does anyone know of other and better wheel options for the class? I have not found any in 16 inch diameter and I have not deeply considered switching to 17'' diameter because I am not sure if there are wheels with the same widths of 6.5 and 7.5 as the stock AP1 wheels.

TiresThis should really come before wheel selection because this is the more competitive selection than wheels. The stock AP1 tires size will net you the best performance based off of my research and other threads that I have found. Therefore the tires if staying stock 16inch diameter wheels you should run are 205/55-r16 front and 225/50-r16 rear. That narrows your selection of completive 200 two tire drastically. I have found myself going back and forth between the Yokahama A052 and the Khumo ecsta v730. I have landed on the Khumo as the best choice because the A052s are way more expensive and from user reviews you really need to run a good deal of camber to utilize their peak performance. With stock AP1 suspension I am not going to be able to get camber to levels that will fully utilize those tires. So the cheaper Khumo and the lacking need of higher camber to fully utilize is why I am going in that direction.

Tire Rules

• You can run any size tires that will fit your wheel selection (again those wheels must fall in the above rules)

I hope this helps others in their C Street wheel and tire search and greatly appreciate any contributors to this threads cause. If this information already exists and I am just missing it please feel free to redirect. Thanks all...happy come killing.

 

The weakness in C Street is weight, low-end power, and narrow front wheel compared to a ND Miata. I'm going to be honest with you and it may be discouraging. That is not the intent but it's reality. S2000s are not the car to have in CS, especially the AP1s. That doesn't mean it's pointless to drive, I just think that maximizing to the rules of C-Street is not very wise unless it's just what you want to do. If that's your goal, you will need to buy the Yoko's or at least Falkens if you intend to maximize the car. Tires are the most important part and Yokos still seem to be the fastest. They're still fast on camber challenged cars, they just wear the outside shoulders really quickly. My 03 was really fun to learn on in the Street classes and I think it was more fun than my 06.

Most important items: Tires and a front swaybar. Buy a Karcepts front sway bar. It's expensive but it's worth it. It's the only adjustment you have in street and it makes a huge difference. I'd adjust mine depending on course. Stiffer for heavy slalom courses, softer for ones with more sweepers.

Sizes: I ran 225 square on OEM AP1 wheels when RE71s were the hot tire. I think Yoko makes a 245/16. I'd be inclined to try 225/245 with the Karcepts .188 wall bar.

Wheels: Wheels are of minimal gain here. I guess I haven't tried them on a stock car but it's low hanging fruit. You're better off saving the money for a second set of tires. You'll need them.

Do you have experience autocrossing? I started 6 years ago thinking I'd do it for 2 years and start tracking. Between being humbled, expenses, risk, and genuinely enjoying autocross, that has not happened. It took me 3 years before taking my first in-class win locally. I forget if the S2k was B-Street or C-Street at that time. I was against pretty good drivers but nobody who would win anything nationally. I just say that to point out that it really is a skilled sport/hobby. More so than people realize until they get really into it. I still think I'm just a good intermediate bordering advanced. It will take time before the driver is anywhere near competitive if you're in a competitive region. Keep at it and keep having fun. I had tons of fun picking who I was going to try to beat at each event along the way. Now I have fun trying to push the S2000 to victories in classes it should not win.

If you're new, keep it simple. You don't need to go out and spend money on parts. Get tires and spend the parts money on school/instructor/test-n-tune days. Hopefully your region does them as mine does and they're very helpful. You need seat time, not parts. Seat time is what it's all about. It's fun and it's how you improve.

 

Thanks for the response. This is exactly the info that I am looking for from owners more familiar with autocrossing the S2000.

I started out autocrossing an NA Miata for two years with the intent of moving into track days/HPDE. The class that I ran the most in my Miata was STR. Locally I did decent and got second place in STR for a season (but when I ran STR down at DC events I would be beaten to a pulp by that STR group). That was when I moved into track events...or maybe I should say stumbled around for a while. This past year was my first full season of ~17 track days. I was able to advance over the years to HDPE group 3 with my Miata at NASA events. What I wish I would have done was start more with an end goal in mind for the Miata because what I ended up with was a car that was fun to run at track days but didn't really fit into any particular autocross or track class. That left me with no competition to compare or push my driving to advance. I don't want the same path for my S2000 and after heavily modifying my Miata I realized that I probably enjoyed the car more when it was closer to stock and I had less into the car.

So for my S2000 I want to modify it to the extent where it fits well in a specific autocross class and gives it a competitive chance to win the class. Really looking for good competition to help push myself and my driving skill, which I consider to be intermediate, I am not superb and humbled when I get to compete with really experienced drivers.

With the prior experience of modifying the Miata extensively. I was thinking a street class would be a good fit by keeping modifications and expense to a minimum. My S2K is currently bone stock and running 400tw tires in C Street. I normally keep in mid pack of my local C Street class but can't really compete with the top with the current tires.

My main goal here is to have a competitive S2000 in autocross where the winning or losing comes down to driver skill and not as much "car". Then get a bunch of seat time and schools under my belt in the car. Maybe there is another class that I should be considered heavier than C Street? Maybe STR but I think the ND2 Miata is really shining in that class as well?

If I do continue to run in C Street I will for sure be getting a competitive 200tw tire and based off of your recommendation maybe I should reconsider the A052s and the Falkens potentially in a square set up.

 

As Jub mentioned, finding the perfect C street spec wheels is pretty difficult. So few wheels available in that specific spec, at least none that I can think of off the top of my head. And if there were some custom spec available I'd bet it would be pretty expensive, difficult to find, and have long order lead times. Those Work wheels likely will be custom order and have very long lead times from Japan, not to mention the JDM bling tax. Better off just going with OEM and getting more seat time.

My car is a bastard STR spec but I have driven my buddy's C/B street spec car with 225 non stagger on stock wheels and a Karcepts front sway bar. It will probably depend on your local course/autoX pad but mine is pretty tight and my buddy could keep up with one of the local heroes in a B street M2. I see some people argue that 205/225 stagger might be better than 225 nonstagger because of the stupid muffin top with the 225s up front but honestly I didn't feel too much squirm in the steering feel compared to my old staggered AP1 setup so more turn in grip the better with 225s. I think the main life saver is the Karcepts sway bar. It works wonders for tightening up the car's steering response, especially in slaloms. The stiffness rates seem pretty stupid at first but they work. Unfortunately I don't recall his exact settings and sway bar spec.

In comparison my car is 255 non stagger with Ohlins in 10/8k, still on stock '00 AP1 front sway bar. Mine feels much more planted because of the wider tires and the switched up spring rates however honestly his car still felt better in the slaloms likely because of the sway bar. Even with 10k springs up front my car still feels slightly lazy in slaloms and has a bit of slop in the transitions. His car was much twitchier but you could always catch it which made it more difficult to drive but doable.

As far as tires go, I haven't used either (went with RT660s) however from reading the Yokos likely will be faster than the Kumhos. From what I've read the Kumhos are more of a track oriented tire targeting more heat capacity and endurance rather than instant grip.

 

The ND2 effectively killed the S2000 in STR. My car is pretty much full try-hard STR prep. S2000s are no longer in STR and now in SST. SST is basically STR mods but you can roll your fenders and fit massive tires. You also need to compete against some pretty fast cars. Jury is out on whether s2000s will be competitive in it or not. There's a separate thread for that argument in the Racing and Competition section.

I guarantee you a S2000 can win STR and C-Street in the DC region. I will find out about SST this year. C-Street is a really fun group of people to run with in DC too. I had a lot of fun in that class. There is still an AP1 driver that does pretty well in the class. I know he took at least 1 event win last year. I know he was on the Yoks on stock wheels but I don't know his sizes.

If I were in a stock AP1 and trying to find a setup to put me into contention locally, I'd be buying 225/245 Yokos and a .188 wall bar. That setup should be good enough to win locally. It's on the driver until the guy you're against is a nationals contender or you're within a second from them.

 

Thanks all for the input. I ended up going with a set of Fallen RT660s in 225/50 square and picked up the karcepts front sway bar in 0.188 wall thickness.

They probably will not be as fast as the A052's but if I am being honest with myself more seat time would definitely help. If/when I become competitive with the RT660s then I will jump to the A052s. Given that I am probably going to get better wear out of the RT660s I felt like they were the right option for me. I'll comment later on what I think of running the RT660s in 225/50 square.

 

For wheels one option would be the jdm bbs ap1 wheels. They are the same specs and oem ap1 wheels but are forged and therefore lighter. Beyond that with this restrictions I’d just stick with the oem wheels since I think you’ll be hard pressed to find aftermarket that fit the requirements.

 

Awesome, those are really good choices overall. I was tempted to save some money with the RT660s myself this year but I have liked the Yoks. All you need now is a good alignment and you're good to go. Max camber front (should be 1.7 degrees each side), I think I ran about same in rear, 0 toe front, rear toe is arguable. I've driven both high and low toe on your exact setup except RE71s instead of the RT's. I preferred high toe.

 

I am probably going to run the current alignment as long as there is no rubbing on the front tires (which tire rack called me concerned about rubbing but pretty sure 225 square with my camber should not cause rubbing). I had the alignment checked when I got the car below are the specs that my local shop said the car had.

CamberFront: -1.5
Rear: -2

Caster: 5.5

Toe:
Front 0
Rear 0.1" (total)

It will probably be close enough for now. If I go back and have it aligned later this year I'd probably ask for more front camber.

Tires should be arriving tomorrow and mount and balancing shortly there after.

 

Nice, you should be in a good place overall. They may be a bit wider than my 225 RE71's were but I think you'll be fine. I think I did have the tire shoot a clip out of the fender liner with that setup but I don't think you're going to be anywhere close to catching a fender or anything. I ran a 245 front on my AP2 in CS and it was fine too. More fender liner clips eaten up than the AP1 setup though.

TireRack is just skeptical to do anything outside of factory spec so they'll provide disclaimers like that. They don't want to be liable is really it.