Auto-x F80 B Street tire setup - help needed

[electricbrew]

Hey guys -

TL/DR; What are the widest 200TW tires that I run on stock wheels w/o rubbing, spacers, or fender rolling?

If you want more info ...

I'm still relatively new to auto-x with 3 events under my belt, all in my E90 335i in F Street/Novice. I've got a roadrace background, but auto-x fits my current lifestyle better. While I've been autox'ing the 335i, I've been rebuilding a salvage F80 that will take over as my daily + auto-x car. I want to keep the M3 in B Street and keep it daily drivable, but I want to have a set of dedicated auto-x wheels/tires for it.

I've got a set of 18" style 513M wheels and a set of 19" style 437M wheels. Both are 9.0 front and 10.0 rear width. I like the look of the 437M wheels better, but are the increased weight and smaller sidewalls a detriment vs the 18" wheels? Are the 18" inner diameter tires easier to come by and cheaper than the 19" ID tires?

What are the best options for either of these wheels in terms of tire size that will fit w/o rubbing/fender rolling (since that's not allowed in B Street), performance, cost/longevity value, and availability? Is there a particular brand that makes the best width and sidewall aspect? I can space up to 7mm if necessary to avoid inside rubbing, but would prefer not to if I can avoid it.

Really I'm interested in any thoughts, experience, or wisdom on what fits and works well on these cars and any other tips on setup or whatever people want to throw out there. I've been daily driving my F80 for about a month now, but haven't yet actually done any kind of performance driving with it so I'm brand new to it in that sense. Thanks!

[Theruleslawyer]

You can probably put a 295/35 on the rear. However most isn't always fastest. 285 would be safe if you can find the tire you want. Up front no more than 275. 265 would be better supported. I run 275/295 35 r 18 for my autox wheels. However those are 10/11 18 wheels.

If you have a dct I encourage you to stick to stock diameter. Redline in 2nd is on the low side. MT you might be able to get away with a slightly shorter tire with the longer 2nd.

None of those will have issues fitting. Remember that most 200tw are quite wide for the nominal size. Even though 265/285 is a stock size they are significantly wider.

Sometimes your choices wil get dictated by what tires you want. Wider tires get spotty. I run re71rs for autox.

[electricbrew]

Thanks for the input! I do have the 6MT, but thanks for the heads up on the gearing. I was initially thinking 275/295, but I like the idea of 265/285. Unfortunately though, it seems like 285 35 availability is a problem, especially in 19". The RE-71S has one, but doesn't have a 265 option for the front. The only option I'm getting on tire rack for 265/285, even for 18", is the Hankook R-S4. Digging into that one, it does seem like a reasonably performant and long lived tire for the money though, so that could be a decent option. It seems like several of the makes don't have anything between 275 and 305 in 18" or 19", which is a bummer for me for rear fitment. The ones that do mostly don't have great front fitment options. Do you have any experience/advise on running different brands front to rear? I'm starting to think about it since they won't be rotatable on my setup and will have different wear/grip characteristics anyway based on size and usage. Maybe this is dumb though and I just don't know better yet.

I don't have any particular affinity to tire brand at this point. When I roadraced, we had a spec wheel size and tire that we had to use in my class, so I never had to put any thought into this. My thought was to get something on the cheaper end for now that will be better than a "street" tire, but not heat cycle out before my driving skill can even fully take advantage of the performance capabilities of the tire. Honestly, after saying that, I'm kinda wondering why I'm not just going 255/275 and seeing where that gets me for the first set. I'm not even competing at this point since it's the middle of a season and I'm in the novice group anyway. I guess it's just my competitive background that makes me always want to optimize the car setup.

[Theruleslawyer]

The rs-4 isn't a good autox tire. It takes too much heat. I had a set for hpde and tried them at autox and they only started sticking after the 5th or 6th run on a warm day.

https://grassrootsmotorsports.com/ar...-buyers-guide/

Pay attention to the "warmup" column in the table at the bottom. The best autox tires have A warmup and A time trial pace.

RT660 are pretty popular. If you're novice and not really competing for top spot something B/B will be fine if you can find sizes that work.

These rt660 would probably work well for you.
https://www.tirerack.com/tires/tires...60XL&tab=Sizes
https://www.tirerack.com/tires/tires...60XL&tab=Sizes


The re71rs I'd go for this probalby
https://www.tirerack.com/tires/tires...RSXL&tab=Sizes
https://www.tirerack.com/tires/tires...71RS&tab=Sizes

If you're willing to run the 18" wheels tires do tend to be cheaper.

Id price out a couple brands though. There can be a considerable difference. 255-275 fronts, 275-295 rears.

[electricbrew]

Awesome! Thanks for the link to the GRM breakdown and the suggestions. It's a huge help!

[Theruleslawyer]

Originally Posted by electricbrew

Awesome! Thanks for the link to the GRM breakdown and the suggestions. It's a huge help!

Sure. One last thing. Prioritize front tire size if having to pick. IE if you can get a 265 up front and only a 275 in back thats better than 255/285

[DeTh]

I have 305/30r19 Cup 2's on 19x10 et 42. Stock 19's is et40.

[electricbrew]

> Prioritize front tire size if having to pick. IE if you can get a 265 up front and only a 275 in back thats better than 255/285

Thanks for this. I think this was exactly what I needed to make a decision. The understeer at turn in is my biggest complaint in the 335i so far w/ the 225 f 255 r stock setup. I feel like I can manage the oversteer and wheel spin on throttle out better than the front end washing away.

After reading up on everything and looking through options, I think I've decided to go with the Ecsta V730's on the 18's in a 265/35 f and 275/35 r configuration for my first go-round. They seem like a good mix of cost/performance value, fire up, longevity, availability, and sizing for someone who's learning and going for consistency/improvement rather than every last tenth. I was a little tempted to go 275 f 305 r on the 19" wheels, but Kumho set the minimum wheel width for the 305 at 10.5". Even if it would work with a 10" wheel in theory, I'd probably have trouble getting a shop to mount them.

[RugbyBro]

Any reason why you wouldn't run 275 square with the V730s?

Edit: NVM just saw you have 9.0in front. 265/275 stagger will still work well.

[Theruleslawyer]

Originally Posted by electricbrew

After reading up on everything and looking through options, I think I've decided to go with the Ecsta V730's on the 18's in a 265/35 f and 275/35 r configuration for my first go-round. They seem like a good mix of cost/performance value, fire up, longevity, availability, and sizing for someone who's learning and going for consistency/improvement rather than every last tenth. I was a little tempted to go 275 f 305 r on the 19" wheels, but Kumho set the minimum wheel width for the 305 at 10.5". Even if it would work with a 10" wheel in theory, I'd probably have trouble getting a shop to mount them.

That should be a solid choice. Let me know how you like them. I've been eyeing them for my HDPE tires once the rs4 are done.

[electricbrew]

Cool. It'll probably still be a couple/few months before I actually get the M3 out on them, but I'll report back once I do.