[ggggbmw]

I'm planning on buying a set of wheels/tires for track use. Mostly HPDE/PDX, but I'd like to start doing some autocross as well. The local MAC autoclub also does some time trials based on SCCA rules/classes.

I'd like to stay in F-Street class. I know the 235 isn't really competitive in FS, and I'm really not, but it's worse in STU. Also, if I stay in FS, it limits me from spending money on things like suspension mods and power upgrades. Things that start compromising my daily driver from comfy long distance use. Also a good mental limit to keep my wallet in check.

The downside with FS is that you have to stay with the OEM stock wheel width. In our case, that means 7.5". Yes, my staggered are 8" in the back, but only legal in back. Not on the front, and not squared. Prefer to run square so I can rotate tires and maximize wear, so that means 7.5" all around.

So, thinking a 17x7.5 ~ET40 wheel. Probably with 235/45-17 Hankook RS4.

The big problem I'm having is finding suitable wheels. There just aren't that many 7.5" wheels around. 17" or 18". Lots of 8" or 8.5" choices, but 7.5" is rare. Especially in lighter weights, and with the ET45-ET38 allowed by the rules.

Tire Rack has the Monte Titano, MT6 Vita, ET40, 19.95lb. About ideal, sizewise. But I don't know if it has stock bore and uses stock bolts (yet). And with the weight of the RS4 tires, I'd like to go lighter if possible. The other choices TR has are all heavier, or expensive, or both.

ECS and BavAuto have nothing in a 7.5". ECS does list several BMW OEM in 7.5", but they are all $300+ each. They don't list weights, but the stock BMW wheels are not light. If I'm spending that much I'd like something more like an ARC8 (which don't appear to be available in 7.5").

So, does anyone have any other ideas for a good 7.5" wheel? Prefer 17", but I'd consider 18" also. Willing to spend on better rims if they are light.

Or, is there something wrong with my logic? I know a lot of people are running the TR Motorsports C4 17x8xET40 with a 245/40/17 RS4. Am I getting too hung up on the F Street thing? Am I misreading the rules?

[TajoMan]

You read the rule correctly.
We are stuck with 7.5" rim and that's the biggest reason (I think) that it's not competitive in FS class.

M2 is very good in BS. There is no reason why M235/240 can't be competitive IF We Have 8 or 8.5" wide rim so we can put 245 or 255 tires.

I'm going first Auto X with this car this weekend. I will see how bad it is. lol

[ggggbmw]

Originally Posted by ggggbmw

Tire Rack has the Monte Titano, MT6 Vita, ET40, 19.95lb. About ideal, sizewise. But I don't know if it has stock bore and uses stock bolts (yet).

Tire Rack did confirm that these wheels do have the correct 72.6mm center bore, and use the stuck lug bolts. Unless anyone can offer a better idea, it looks like these are my best option. (They look nice too. Bonus.)

[Maynard]

I run Sparco Pro Corsa 7.5-17" ET43 wheels for my winter wheels. Not super-light (22#), but also don't appear to have bent or warped under fairly harsh winter road use. TR only has them in silver, but they also come in other colors (Mine are flat black, also think there is a gunmetal or dark grey, gold). You might also check specifically w/ your local governing group to see if they'd OK 8" - I've seen others posting about being allowed mild changes w/i regional competition (didn't sound like you were headed for the Nationals).

[ggggbmw]

Originally Posted by Maynard

I run Sparco Pro Corsa 7.5-17" ET43 wheels for my winter wheels. Not super-light (22#), but also don't appear to have bent or warped under fairly harsh winter road use. .

Thanks for the tip. Unfortunately, it doesn't look like TR stocks these in a 17" anymore.

At least not at present. When I bought snows on 17" last year, I vaguely remember having a lot more choices. I'm wondering if TR is wiped out of 17's after selling a ton of snow tire packages this year. Certainly was a good year for snow.

In any case, I ordered the MT Vita this morning. Don't think I'm going to find a better choice for the money.

Also decided on doing the 225/45-17 RS4. After digging a but further the 225 is 2 pounds lighter than the 235, and is only 0.1" narrower. Also, the 225 will fit the 7.5" rim better, for less sidewall flex. And it is smaller for better gearing acceleration.

RE-71 would have been a better autocross choice, but I'd rather have the better heat resistance of the RS4 for track days. (Yeah, schizophrenic choice staying 7.5 for FS, but didn't pick the best tire for FS auto-x. But, choosing to stay FS is more about choosing an artificial spend limit then ultimate performance.)

[SteveInfante]

Yeah my 228 is in ST now because of my upgraded brake pads, stainless lines, tune. I went to 225/45-17's on the stock 7" snowflakes. Even if my car isn't competitive, which I'm sure it isn't, it sure is fun. That's all I really care about.

[TajoMan]

Originally Posted by ggggbmw

Thanks for the tip. Unfortunately, it doesn't look like TR stocks these in a 17" anymore.

At least not at present. When I bought snows on 17" last year, I vaguely remember having a lot more choices. I'm wondering if TR is wiped out of 17's after selling a ton of snow tire packages this year. Certainly was a good year for snow.

In any case, I ordered the MT Vita this morning. Don't think I'm going to find a better choice for the money.

Also decided on doing the 225/45-17 RS4. After digging a but further the 225 is 2 pounds lighter than the 235, and is only 0.1" narrower. Also, the 225 will fit the 7.5" rim better, for less sidewall flex. And it is smaller for better gearing acceleration.

RE-71 would have been a better autocross choice, but I'd rather have the better heat resistance of the RS4 for track days. (Yeah, schizophrenic choice staying 7.5 for FS, but didn't pick the best tire for FS auto-x. But, choosing to stay FS is more about choosing an artificial spend limit then ultimate performance.)

RS4 has widest thread width among 225/45 17. It's almost as wide as 235.

[ggggbmw]

Got the RS4 225/45-17 mounted on the car, on the Monte Titano MT6 Vita 17x7.5 ET40.

Initial Driving Impression
So far this is just around town and a few twisty bits and on-ramps. Compared to the stock 18" 225/40 MPSS the 17" 225/45 RS4 are definitely stiffer, and seem to stick better in long sweepers. The RS4 has a good on-center feel, and the turn-in is agressive, although once you're in the turn the feel deadens a bit. I'm a bit worried when they do cut loose it will be more abrupt than the MPSS. We'll see when I get on the track and can push them harder (and where hopefully any runoff will be soft ).

They are really noisy compared to the MPSS. A constant howling sound. I've driven worse, but I really like a quiet car cruising on the highway, and the MPSS has the RS4 beat here.

On the whole, for street use, the MPSS is the superior tire. Quieter, softer ride, and the initial turn-in is nearly as sharp. But I can already feel the RS4 will be better on the track.

Visuals
You can't really appreciate how massive the RS4 225 is until you see them next to the stock MPSS. Here they are compared to the stock 225 MPSS. You can see how much wider the tread is. You can also see why the MPSS with their big channels are way better in the rain.


Here they are compared to the 245 staggered rear MPSS. Nearly the same contact patch.


Below are some pictures of them on the car. Not too ugly, but being a stock size they don't really fill the wheel well. The ET40 gives them a tiny bit of more aggressive poke, but still leaves lots of clearance if I want to try a 235 next. My winters are on ET32, and they poke too much. (Not enough to rub, but looks funny.) The ET40 being close to the stock ET45 should also lessen some of the twitchiness the ET32 can give me.


Front clearance


Rear clearance

[cxp213]

Originally Posted by ggggbmw

RE-71 would have been a better autocross choice, but I'd rather have the better heat resistance of the RS4 for track days. (Yeah, schizophrenic choice staying 7.5 for FS, but didn't pick the best tire for FS auto-x. But, choosing to stay FS is more about choosing an artificial spend limit then ultimate performance.)

Hoosierstones would've been better all-around, regardless. I've had several sets and I ax/track in Texas. The temps you'll see will never come close to the summer temps experienced here, so you're fine.

Considering that you're not really competing at the higher levels or possibly even campaigning locally, I think you should focus less on the FS specifics and just enjoy the seat time.

[TajoMan]

I'm curious how RS4 will run against RE71 in this size (225/45/R17) since the thread width of RS4 is 0.7" wider than RE71.

Tirerack's test was with 245/40/R18 (0.5" wider thread with RS4).
Lap time and slalom time were very close (RE71 was slight faster).

Also curious how the new Star spec 3 will do comparing these tires.