Autocross- SCCA EV-X Class vs. SS

[Rodney!]

question for my solo brothers: stock suspension M3P w/ 18x9.5 +29

What is the biggest tire i can stuff in there and not have any contact issues, both inside and outside?

255/40-18: should fit no problem, correct?
265/40-18: Should be good, but close?
275/40-18: This tire size is brand/model dependent, correct?

Car is on order, hopefully here by the time the season starts here. I plan on futzing around locally, and if I gel with the car then i will go whole hog and dive in. But, I don't want go go max fitment off the bat, on a car that I am unsure of.

Thanks!

 

[gearchruncher]

What is the biggest tire i can stuff in there and not have any contact issues, both inside and outside?

Your question is much more tied to wheel offsets than it is tire section widths.
You can fit a 275 on the car no problem.
In an 18" size you need to pick your wheels carefully to clear brakes. You're going to need a 35+mm offset wheel at 275. 265 with 35 looks really good.
Your biggest issue at AutoX will be limited camber. You'll get more bang for the buck getting camber arms than new tires.

 

[Rodney!]

Your question is much more tied to wheel offsets than it is tire section widths.
You can fit a 275 on the car no problem.
In an 18" size you need to pick your wheels carefully to clear brakes. You're going to need a 35+mm offset wheel at 275. 265 with 35 looks really good.
Your biggest issue at AutoX will be limited camber. You'll get more bang for the buck getting camber arms than new tires.

after weeks of research, wheels are picked, 18x9.5+29. Brake clearance will not be an issue.

No interest in swapping hard parts just yet, save for wheels/tires. So, biggest tire on the above rim, 275/40 will work?

No idea about alignment, as i do not have the car in my possession. Is camber adjustable stock? If so, how much can i get if i loosen/push/pull etc?

 

[gearchruncher]

+29 is pretty wide, and will poke with 265 or 275. With 275 you might have interference from some tread patterns on the fender. More offset would help. You'll be down to the actual tires you are picking at this point- are you planning on running a specific 275 tire?

Camber is not adjustable stock on a Model 3 (beyond a tenth or two from pushing around in bolt holes). The stock camber is right around -0.75 degrees. This should also impact your tire decision as different constructions work better on camber limited cars.

 

[Rodney!]

I don't want to fiddle with spacers/extended studs. Research has shown that 18x9.5 +35 requires a 3-5mm spacer, so i found +29 wheels so in theory i won't need a spacer.

Will probably end up with A052's, but first tire will be A660 or perhaps even the Apex v601.

Thanks for the camber info. I have access to an alignment rack, tire machines etc, so that stuff is easy peasy. But, having never run the car, i cannot comment on it's dynamics, and what it needs/ or what i want it to do.

let it be kown, I hate street tires. When the whiners came out and pushed their "i don't wanna swap wheels" agenda a decade ago, I walked away. Too many tires and possible combos, that it made testing ridiculous. All it it did was make it more expensive for those that run at the pointy end of the stick. Hoosiers were awesome, and being creative, i was able to get them for cheapish moneys. Now, the top tier street tires are way way more $ then i paid for my A3, A4, A5, and A6's.... /rant over.

 

[gearchruncher]

Research has shown that 18x9.5 +35 requires a 3-5mm spacer, so i found +29 wheels so in theory i won't need a spacer.

What? Tons of people run +35 without spacers. I have 3 sets of +35 wheels in 19x9.5. Stock 9" wheels from Tesla are +34.
Plus, running a spacer is identical to offset... The reason you need longer studs is when you have the wrong offset and need a spacer. But there's nothing you can do to go higher in offset once you buy a lower offset wheel, and offset has nothing to do with needing studs.

Now, the top tier street tires are way way more $ then i paid for my A3, A4, A5, and A6's.... /rant over.

Rant all you want, but Hoosier A7's are WAY more than any of the 200tw tires just to buy, and then WAY WAY WAY more per run. Good for you for having a magic place you can get reliable take-offs for cheap, but statistically that cannot work for all people. A Hooiser A7 275/35/19 is $437 at Tire Rack while an A052 is $332.

Street tire limits have made the sport way more approachable, and have led to amazing street tires.

All it it did was make it more expensive for those that run at the pointy end of the stick.

If your goal is to be an alien and you're running your car with stock camber, you're going to be disappointed, and you're never going to be competitive in SS with a Model 3 anyway. Hoosiers wouldn't save you. Go into EV-X and you'll get trounced by those with more camber and shocks. The path to a fast model 3 is well known, and once you do that, it can be a GT3 killer on a lot of courses.

 

[Rodney!]

Wait... I am not an alien? #dammit.

 

[SK360]

This is a 19x10 +35 with a 265/35/19 RE71R (damn those street tires!). No spacer.

For what it’s worth I’m going with a Falken RT660 in 265/35/19 this year since the actual width is as wide as the 275 RE was. I’m anticipating needing a 3mm spacer but didn’t want to get into needing studs if the 275 Falken was too wide.

Also for what it’s worth I wouldn’t be autocrossing if there wasn’t a tire I could drive to/from events on.

 

[Rodney!]

Sk, thanks for the pics! It is very informative seeing tire to spindle clearance. How much room is on the outside with that setup?

I am still playing the numbers game, as i dont have car to actually put a tape measure on. All i know is i want a wheel setup to replace the ubers on day one, and i want something more aggressive, but i don't want to dive into the realm of hard part swapping at mile 1 either.

And yes, i am an old school guy with the "gimme my hoosiers in stock class" mentality. I spent a decade in SM then 5 years in stock on R compounds, and after you taste the purple crack, it is hard to go back to 200 tw...

In full disclosure, i have no interest in the street classes. i was going to build an ASP Z06, but then I drove an M3P, and well, i need a new commuter... Blah... blah... $250 later, here i am. I was talking with a buddy, and he told me about EVX and it sounded intriguing.

 

[SK360]

Sk, thanks for the pics! It is very informative seeing tire to spindle clearance. How much room is on the outside with that setup?

I am still playing the numbers game, as i dont have car to actually put a tape measure on. All i know is i want a wheel setup to replace the ubers on day one, and i want something more aggressive, but i don't want to dive into the realm of hard part swapping at mile 1 either.

And yes, i am an old school guy with the "gimme my hoosiers in stock class" mentality. I spent a decade in SM then 5 years in stock on R compounds, and after you taste the purple crack, it is hard to go back to 200 tw...

In full disclosure, i have no interest in the street classes. i was going to build an ASP Z06, but then I drove an M3P, and well, i need a new commuter... Blah... blah... $250 later, here i am. I was talking with a buddy, and he told me about EVX and it sounded intriguing.

I have MPP Front upper control arms with max front camber they will allow (Somewhere around -2.8 to -3.0, never had it on the alignment rack with the shims out) so I have lots of room on the outside. I don't think +29 will be terrible, you will just need to keep an eye on your fenders on stock camber.

 

[SK360]

UPS just dropped off my tires for this season

 

[gearchruncher]

I'd really just go with a 265 for your first tire. With a +29 offset and no camber, you're already on the edge under compression. You're not going to gain any real noticeable time with a 275 over a 265, and it will poke for sure, so there is some risk it won't fit well or will rub in the corners.

 

[MasterC17]

Sk, thanks for the pics! It is very informative seeing tire to spindle clearance. How much room is on the outside with that setup?

I am still playing the numbers game, as i dont have car to actually put a tape measure on. All i know is i want a wheel setup to replace the ubers on day one, and i want something more aggressive, but i don't want to dive into the realm of hard part swapping at mile 1 either.

And yes, i am an old school guy with the "gimme my hoosiers in stock class" mentality. I spent a decade in SM then 5 years in stock on R compounds, and after you taste the purple crack, it is hard to go back to 200 tw...

In full disclosure, i have no interest in the street classes. i was going to build an ASP Z06, but then I drove an M3P, and well, i need a new commuter... Blah... blah... $250 later, here i am. I was talking with a buddy, and he told me about EVX and it sounded intriguing.

Invest in camber arms. Unless you love paying for tires - which it sounds like you don't. The camber arms will pay themselves back on your first set of tires. Otherwise, your outer edges will be chewed alive and you'll be buying another set of tires very soon.

 

[gearchruncher]

Here's the poke with a 265 on a 19x5, +35mm offset wheel. It's basically exactly flush on the front.

This is also with -2.5 degrees camber, so I'd expect 7mm more poke at the top with 1 degree camber.

So with a 275, +29, no camber, I'd expect +18mm (0.7") farther out.

 

[gearchruncher]

Unless you love paying for tires - which it sounds like you don't.

Didn't you hear, he has a magic source for Hoosiers way cheaper than street tires. NO HARD PARTS that can be installed in an hour. ONLY CHEAP HOOSIERS!

 

[MasterC17]

Didn't you hear, he has a magic source for Hoosiers way cheaper than street tires. NO HARD PARTS that can be installed in an hour. ONLY CHEAP HOOSIERS!

I'm going to guess that heat-cycled out Hoosiers are slower than most new 200TW tires.

FWIW - I fit 295's under the stock bodywork last year and am moving to 305's this year. MPP just ran a car with 305 AR-1's under the stock bodywork.

 

[Rodney!]

Invest in camber arms. Unless you love paying for tires - wh

Invest in camber arms. Unless you love paying for tires - which it sounds like you don't.

Actually, i do...

Point taken, I understand the lack of camber. So these things are basically like the camber challenged minis from back in the day...

 

[Rodney!]

Gearcruncher, stop assuming things about me. You don't know anything about me or my history, so give it a rest.

 

[gearchruncher]

FWIW - I fit 295's under the stock bodywork last year and am moving to 305's this year. MPP just ran a car with 305 AR-1's under the stock bodywork.

I've heard you can do 295+, but part of that is a lot of camber, right?

 

[gearchruncher]

Gearcruncher, stop assuming things about me. You don't know anything about me or my history, so give it a rest.

Sorry, just messing around. Hope I gave you some good info in this thread on fitment. I even went out and took a photo for you and did some math!

If you really do have a good source for cheap Hoosiers that aren't cycled out, I'd love to have it. The just-for-fun club I run with doesn't have any tire restrictions, but at MSRP they are way more than other options. I mean, the current attitude towards A052's is that "they are great if someone else is paying for them" because of how fast they wear, and that goes double for A7's. I've run a set of A7's with about 15 heat cycles on them and they weren't any faster than my MPS4's.