Advice on track wheel/tire combo

[p66]

Working on a track wheel/tire setup for my 1M. I know this is the M3 forum but with the available quipment for the 1M so close to the M3, I hoping this has been addressed before.

Installed AST4200 and Vorshlag camber plates. Considering a 265x35x18 Advan A048 on a 9.5" wheel with an et of 20 in front. Considering a 285x30x18 or 295x30x18 on 10.5" wheel with an et of 27 in back. I know these wheel/tire combos will fit without rubbing when I add some negative camber in front.

Two questions I need help with.

1. Would you start with a 285 or 295 in the back? For referene, the 1M comes with the exact same M3 competition wheels/tires as stock.
2. A 285 would yield a net difference in diameter of 28.5mm smaller than the front. A 295 would yield a net difference in diameter of 22.5mm smaller than the front. Will this large disparity in either wheel diameter cause the traction control system to wig out and give me trouble on the track? With our without traction control on? Or is there a way to reset it using the reset procedure when changing a flat tire?

Thanks a bunch.

[M3 Montreal]

The true track junkies I see go 275 square.

I personally drive street and do between 5 to 8 track days per year so I went with 265 in front and 285 in the rear with NT05's on my TE37 Super Laps. I wanted to get te AD08's but they weren't available at the time. I have to say I'm very impressed with my NT05's so far and my precious tires were RE11's.

[JAJ]

I think either the combos you've come up with will work fine. I found that with better dampers and well balanced springs, you got more out of whatever tires you're using. I could turn faster laps with OEM PS2's after installing the KW's than I could with RComps on the stock setup.

If you know the tires will fit without rubbing, the 295 rears are the better choice because they are closer to the fronts in diameter. On the M3, diameters aren't a big deal: at one point I ran 245/40x18's on the front and 265/35x18's on the back, and even though the rear tires were significantly smaller than the fronts, I had no problems with the TC system at the track or otherwise.

[persian54]

Is a 285/35/18 not available? (I'm unfamiliar with those tires so excuse my ignorance)

I'm personally going to be running a 265/35 285/35 RS3 set up once I get my SLs

Also, I have been advised against running a 285/30 in the rear

[S54dan]

If I were you, I would not stagger the wheels. As posted above, use a square set up. This will help reduce understeer and now that you have the AST's w/ Camber plates, you can play with the settings to see what you like the best. If I were in the same situation, I'd run 275 square.

[LateBraking]

Yep, I'd run 275 square. Used to run that setup and loved it. A error on my part had me scrambling for whatever sizes I could lay my hands on that would fit well on my car, and I'm unfortunately back to running a 265/285 stagger. Once the R-S3's die, I'll be back to basics.

[persian54]

Originally Posted by LateBraking

Yep, I'd run 275 square. Used to run that setup and loved it. A error on my part had me scrambling for whatever sizes I could lay my hands on that would fit well on my car, and I'm unfortunately back to running a 265/285 stagger. Once the R-S3's die, I'll be back to basics.

We should all be men and run 285/35 Square like Ricky lol

[ring007]

275/35 Hoosier R6 square on 10" wheels (you can rotate front to rear and side to side as needed). You will never look back and it will transform your opinion of what the m3 can do on the track.

[///M Ryder]

Originally Posted by Dan@UnitedBMW

If I were you, I would not stagger the wheels. As posted above, use a square set up. This will help reduce understeer

This is a interesting comment. I was just told yesterday by someone that this will definitely increase understeer. I'm considering a square set up right now so I'll stay tuned to this thread..............Phil

[gthal]

Originally Posted by ///M Ryder

This is a interesting comment. I was just told yesterday by someone that this will definitely increase understeer. I'm considering a square set up right now so I'll stay tuned to this thread..............Phil

Square should decrease understeer and increase oversteer. More rubber up front relative to the rear in a square set up than a staggered.

[///M Ryder]

Originally Posted by gthal

Square should decrease understeer and increase oversteer. More rubber up front relative to the rear in a square set up than a staggered.

That's what I thought......maybe he had too many drinks at happy hour and got confused........Phil

[p66]

Originally Posted by persian54

Is a 285/35/18 not available? (I'm unfamiliar with those tires so excuse my ignorance)

I'm personally going to be running a 265/35 285/35 RS3 set up once I get my SLs

Also, I have been advised against running a 285/30 in the rear

I can't find an R comp in a 285x35x18. Nothing under a tread wear rating of140 exists. And I'm not sure a 275 will fit the 1M in front. It will be very, very tight. And I don't want to modify any body work. This baby needs to stay in stock condition. Bolt-ons only.

I think I'm going to go with the 295x30 because it will be a smaller differential between the front and rear tire diameter. If I don't like the handling I can experiment with a 275 up front or try 265 square. All tires are temporary anyway. And the wheels I'm using are very affordable. They are essentially test wheels so that I can dial into the perfect offset. I had plans to replace them regardless.

And thanks for all your advice M3'ers. All I hear are crickets on the 1M forum.

[p66]

Originally Posted by JAJ

I think either the combos you've come up with will work fine. I found that with better dampers and well balanced springs, you got more out of whatever tires you're using. I could turn faster laps with OEM PS2's after installing the KW's than I could with RComps on the stock setup.

If you know the tires will fit without rubbing, the 295 rears are the better choice because they are closer to the fronts in diameter. On the M3, diameters aren't a big deal: at one point I ran 245/40x18's on the front and 265/35x18's on the back, and even though the rear tires were significantly smaller than the fronts, I had no problems with the TC system at the track or otherwise.

So JAJ, when you used this tire combo on the track, with TC on, you could not detect any unusual intervention? That's promising since the diameter difference in your F to R is greater than my proposed 265x35 / 295x30.

Another question I forgot to ask the group. 18" or 19" for track wheels? I suspect 18 but thought I'd ask.

[JAJ]

Originally Posted by p66

So JAJ, when you used this tire combo on the track, with TC on, you could not detect any unusual intervention? That's promising since the diameter difference in your F to R is greater than my proposed 265x35 / 295x30.

Another question I forgot to ask the group. 18" or 19" for track wheels? I suspect 18 but thought I'd ask.

That's correct. I typically ran with sport mode on - if you're smooth, you can go fast without it getting in the way.

18" rims give you access to cheaper tires in a wider array of brands and compounds. The field narrows considerably with 19" rims.

[1MORELAP]

I run 265/285 RS3s and will go to NT05s when I can. I got identical ET25 10" wheels for F and R so I can go square if I want. But keep in mind that a 265 tire compared to 285 on the same 10" rim is really not much different in width. I like to keep the rolling diameter difference closer to stock, as I do run MDM in wet and will continue to do so on my street car.

From what I read, M1 does NOT need more over steer. I would NOT go square on M1, at least not be one of the first. My ZCP (lowered) M3 does not need camber plates. After pulling pins my pyrometer tells me I have too much camber. (Doing more testing on that.)

I think 265/285 NT05s or RS3 would work for you. BTW, I found the "best" wheel to be the Enkei NT03-M. It does fit our M3s. (Cheap and light.)

Little more on my setup. ET25, 10" wheels. That means that my fronts have a wider track than stock. Similar to adding 10mm spacers. Rears are stock track, just wider tire. I also pulled the pins and run good amount of camber up front. These changes have eliminated any under steer the car had. Going square would go too far in my opinion. Now going square and adding spacers on the rear of the car may work. Finally, 265s up front definitely take away steering crispness and feel heavier. 275s or 285s would be even worse. Will see how I vote at the moment of truth, when I buy my next set. But not yet convinced of the square setup yet.