mayday1

I picked up a '99 996 a couple of months ago. Did a couple of autox and
the tires on the car are quite crappy (4yr old hankook evo v12). I don't think
the car is competitive in Astreet, so don't intend to build it up. Still,
I want some decent rubber to get a feel of what the car can do.

I'm thinking of bridgestone re71r, stock size would be 225-40-18 on 8" rims,
265-35-18 on 10" rims in the back. Costco doesn't have
these but does have 235-40-18 and 275-35-18 for about the same
price as tirerack?

Are 235-40-18 too pinched for the front 8" rims? I think 275 for the 10"
rims are fine in the rear since people run 275 hoosiers on 10" rim in CSP
miatas and seem to work well. I assume the 10mm
width increase will not cause fender clearance problem. My suspension
is stock as far as I can tell (not M030 package).

Any other suggestion? I'm perfectly happy to get a lower perf tire
for less money since this is my weekend cruiser and not my primary
autox car.

thanks

sjfehr

I'm running 255/35-18 RE-71R on 18x8" wheels on my 987.2S; you shouldn't have any problems with 235/40-18.

mopar bob

I'm also running 255x35x18 on 8" and also running 285x30x18 on 10's. Welcome to the club and the best thing to do is have fun and get seat time.

jbrennen

My 2003 Lancer Evo, certainly a performance car, came with 235 tires on 8 inch rims. I've run 245 tires on 8 inch rims on that car with no problems at all.

So no, I wouldn't hesitate to run 235 tires on 8 inch rims.

mayday1

When I wanted to change from 205 to 225 on my 7.5" wheels, lots of
more experience autoxers advised against it, and told me that I really need
9" wheels to get 225 to work at its best. Hence my worry that 235
would not work on 8" wheels.

To clarify, I'm not trying to fit the biggest tire on the stock wheels,
I am just trying to get the most grip using the stock wheels.

I'm on vacation for a while so will be taking about a month's break
from autoxing, so there's more time to decide what size to get.

Thanks

PedalFaster

There's definitely a point of decreasing returns when it comes to stuffing street tires, but I think 235 RE-71Rs on an 8" rim are very reasonable.

Not an exact match for your wheel sizes, but last year I ran a C5 Corvette with 8.5" front wheels. There was a lot of debate over whether 255s or 275s worked better on the front end of a C5, and lots of national-level drivers (myself included) tested both. The majority preferred the wider 275s, with one major exception (in my opinion, the fastest driver in B Street last year, although he didn't win the national championship) who was faster on, and strongly preferred, the 255s. I personally found no significant difference between the two, but opted to run the 275s due to increased heat resistance.

You've got a half inch less rim, but you're also considering a tire 20 mm narrower than the narrowest one typically run by Corvettes on their 8.5" rims. I think you'd actually have room to go wider, would probably not be giving up much if anything versus a wider tire, and almost definitely would not be giving up anything relative to a narrower tire.

sjfehr

You're both right.

225 is better than 205 on 7.5" wheels.

Those 225s will work better on 9" wheels than 7.5". But if you're running 9" wheels, you'd be better off running 275s, etc. The real difference is who you ask: were these autocrossers running SCCA Street Touring classes by any chance? Classes limited by wheel width tend to run as wide as possible without getting ridiculous. Classes limited by tire width tend to run those tires stretched onto wider wheels.

mopar bob

235 on an 8 is what is stock factory setup for my car on the front.

mayday1

Just an update since I was the OP.

I ended up getting stock size (225-40-18, 265-35-18) Falken RT-615K+ from Tirerack a couple months ago. I don't think many people have experience
with them. I've about 60 runs on them. So far, wear is decent (I expect
at least 100 runs out of the set), works great immediately from cold.

Compared to re71r (not a real comparision since I've had two sets of
different sizes re71r on a E street miata, a very different car), my gut
feeling is lateral grip is almost as good, but braking is noticeable worse
than re71r in a miata. My guess is my Astreet 996 feels about the same speed as my Estreet miata. Obviously course dependent.

But I think I'll switch back to re71r next time. Falken's runs/$ isn't really better than re71r
because you can flip re71r half way through to get more life out of them
for cars that have softly sprung stock suspension and are camber challenged.
You can't flip the asymmetric Falkens so when the outside edges
are gone you have to get new ones.

knfeparty

A lot of the asymmetric tread tires can be flipped for use in the dry, but when flipped the wet performance will be very bad. I flipped my Rival S with no issue.

mayday1

It probably depends on if the sidewall/carcass is also asymmetric. I think in a couple of months mine will be around half worn, and I'll have to decide whether
or not to flip.

Micaceli

So don't want to start another thread but my 2000 c4 needs new tires and I want to keep it AS legal but I guess take it out of the PCA stock class (I wish they used SCCA classing like everyone else...sigh)

I've done ok with Sport suspension and the stock sized re71r's, BUT I like to tinker. I want to get a set of 8's and 10's, I think Apex might make a stock sized set for us as I have been talking to them about it, we shall see.

If you guys can confirm my math that would be great. I know 285/30's will fit on 10's NP, I am debating on 245's vs 255's, I think I have a guy that can stuff them on the wheel and I think 255/35's will be perfect for 285/30's AND I THINK that the rolling diameter wont mess with awd with those sizes right? If I had to go 245's would that be a problem?

I want to do wheels and tires first. Then maybe MCS with stock perches and then a sway bar if needed. I am going to try to do this in stages unlike my other cars where I am throwing parts at them.

burglar

What does it take to stay in PCA stock? If it's just an "oem only" tire width thing I'd stay with OE sizes. You don't gain a ton by stuffing a tire on the same size rim.

I wouldn't, however, give up the RE71/Rival S/whatever comes out for 2018 unless you absolutely had to.

Micaceli

In PCA showroom ,or something like that, yes has to be same tire size. I run 7.5's up front now with 225's the 8's came with 225's also, just does not seem like enough tire for a c4, its a heavy piggie.

Yeah I am not sure when I will be able run SCCA next year just trying to get the most grip out of the car.

sjfehr

It sure would be nice if PCA mirrored SCCA's Street class allowances so we could run the same car with the same prep with both clubs. But, alas, swaybar and 20mm wider tires bumps me into a class where it's irrelevant because local PCA hasn't had an autocross in 7 years. I think a mini cooper took raw FTD their last local event, lol.