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[LarThaL]

If you increase the stagger from the stock 245/265 to a 255/295 set-up is the increase in understeer really noticeable, or not really?

Is the added grip worth the trade-off? I don't want to go wider than 255 in front because I want to maintain steering feel, but also want to maximize rear grip without increasing understeer during more aggressive driving. Is a 255/275 set-up the best way to go?

[s85e90]

You can have an alignment to dial back out the understeer. I run 245 fronts and 285 rears.

[Hujan]

Good question. I would like to know others' experiences as well.

I assume that understeer/oversteer is a function of grip. The wisdom being that if you reduce front-end grip and increase rear-end grip on the E92 M3, you will increase understeer. Assuming that's the case, I found it interesting that Michelin PSS in 255/35/19 on 9" wheels actually have a bigger contact patch (narrower but much longer) than Michelin PSS in 275/30/19 on 9.5" wheels. (Michelin PSS in 295/30/19 on 10.5" wheels have a larger contact patch than 275/35/19 on 10" wheels, though.)

Thus, if that data is accurate, it would seem that the overall grippiest setup (at least on Michelin PSS) would be 255/35/19 on 19 x 9" wheels up front, and 295/30/19 on 10.5" wheels in the rear.

http://bndtechsource.ucoz.com/index/...alculator/0-20

[1MOREMOD]

Originally Posted by s85e90

You can have an alignment to dial back out the understeer. I run 245 fronts and 285 rears.

This. If it's for street doesn't matter much anyways.

[Flying Ace]

255/295 what tires will you be buying?

[1MOREMOD]

I drink old E to increase my stagger.

[LarThaL]

Originally Posted by 1MOREMOD

This. If it's for street doesn't matter much anyways.

Actually I am gearing up to spend more time at the track. A really nice new track is being built 20 minutes from where I live. I will be buying a club membership.

Yes, yes.....I know about understeer, stagger, etc, but that is why I am wondering if this amount of increased stagger and increased understeer is more theory or is it a real phenomenon. The GTS M3 uses a 255/285 set up so 30mm obviously works just fine. I don't care about the fastest times, etc. I am not racing for money. It is all about fun and the subjective driving experience.

I am looking for the best possible combination of feel, responsiveness and grip at track speeds, as opposed to street speeds. Again...I am not looking for the set-up that will necessarily give me the fastest time, just the best subjective track experience. My top choice right now is actually to go with a 265/35/18 and 285/35/18 set-up on Apex wheels.

Here is the track at Palmer Motorsports Park in Palmer, MA. Scheduled to open spring/summer of 2015:

https://www.youtube.com/watch?v=A7VmLvAVBrI

[surlynkid]

i run 265/30 and 295/30 on the street. But that is the street. I am not doing anything ridiculous enough on the street for understeer to matter. 275/35-18 at the track.

[1MOREMOD]

I've always used square set up at the track. Car from factory has less grip up front and want to reduce that tendency. Adding front camber and width of front tire is how most achieve that more neutral balance.

[Hujan]

I am running 275/35-18 front and 295/35-28 rear G Force Rivals on Apex EC-7 on my track wheels. No track time with them yet, but just from playing with them on the street I'm pretty excited about their track potential.

[bigjae1976]

The only reason I run a square sized tire setup is so that I can rotate tires. What a PIA if you cord a front tire and you only have an extra rear tire.

Run a staggered set up. Stuff as much back there as you can (that's what she said). In an ideal world, I'd run 275/295.

[Richbot]

Don't just look at width when considering stagger. A 245/40-18 front and 285/40-18 rear, for instance, would yield a car with more steady-state cornering Understeer but more wheelspin on corner exit due to shorter tire with shorter sidewall and gearing, all else being equal. I haven't tried it yet but I think this car's happy place (because you can only run so much front tire) may be a 275 front and rear setup, with a taller rear aspect ratio

My theory is that What the car, which is somewhat pushy-loose from the factory, needs is better corner entry to apex grip (bigger front tire) and more throttle-on grip (taller rear tire) to balance that extra front grip once you start feeding in throttle. A 275/295 setup gets you part way there that's what I'm running now, but still feel now that I have all this front grip the rear starts to run out of stick when I ask it to power out of corners mostly due to overpowering the outside rear when feeding in throttle.

[bigjae1976]

Originally Posted by Richbot

Don't just look at width when considering stagger. A 245/40-18 front and 285/40-18 rear, for instance, would yield a car with more steady-state cornering Understeer but more wheelspin on corner exit due to shorter tire with shorter sidewall and gearing, all else being equal. I haven't tried it yet but I think this car's happy place (because you can only run so much front tire) may be a 275 front and rear setup, with a taller rear aspect ratio

My theory is that What the car, which is somewhat pushy-loose from the factory, needs is better corner entry to apex grip (bigger front tire) and more throttle-on grip (taller rear tire) to balance that extra front grip once you start feeding in throttle. A 275/295 setup gets you part way there that's what I'm running now, but still feel now that I have all this front grip the rear starts to run out of stick when I ask it to power out of corners mostly due to overpowering the outside rear when feeding in throttle.

I think the biggest problem with the OE suspension is the lack of travel. I've got a Dinan stage 2 and had GC plates. I know I'm on the bump stops whenever you add a considerable amount of power and more rear spring would certainly help.

I never thought of running a taller tire in the rear to help that. Interesting. I'd try and fit a 305 but now you are talking about some serious tire money. Screw that....I'll just drift my way around thank you very much!

[FogCityM3]

Believe the M3 GTS also runs spacers at the front and rear (with wider front spacers). This will have the effect of dialing out some understeer, so you have to look at the combination of track (offset) in addition to tire sizes.

Originally Posted by LarThaL

Actually I am gearing up to spend more time at the track. A really nice new track is being built 20 minutes from where I live. I will be buying a club membership.

Yes, yes.....I know about understeer, stagger, etc, but that is why I am wondering if this amount of increased stagger and increased understeer is more theory or is it a real phenomenon. The GTS M3 uses a 255/285 set up so 30mm obviously works just fine. I don't care about the fastest times, etc. I am not racing for money. It is all about fun and the subjective driving experience.

I am looking for the best possible combination of feel, responsiveness and grip at track speeds, as opposed to street speeds. Again...I am not looking for the set-up that will necessarily give me the fastest time, just the best subjective track experience. My top choice right now is actually to go with a 265/35/18 and 285/35/18 set-up on Apex wheels.

Here is the track at Palmer Motorsports Park in Palmer, MA. Scheduled to open spring/summer of 2015:

https://www.youtube.com/watch?v=A7VmLvAVBrI

[Richbot]

I agree this car corners on the bumpstops in stock form frequently but I also don't think the bumpstops on this car are all that harsh a transition. Travel when you start compressing the bumpstops is still travel and the stops on this car are long and very progressive otherwise with the very soft stock spring rates (considering how heavy it is and how much grip it generates, about 1g on modern tires like the PSS) the car would ride like an anvil and be useless over bumps even when stock, and we know that's not true.

So if you're interested in staying with near stock spring rates you're going to be on the stops anyway and might as well find other ways to get the balance right

I also agree sideways are the best ways

[bigjae1976]

Originally Posted by Richbot

I also agree sideways are the best ways