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      08-11-2009, 10:29 AM   #1
R32
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Non-staggered track setup?

greetings!

i am looking to get into a z4 m coupe in the next couple of months. i plan on getting a set of track rims pretty much right away. i am an intermediate track driver-- i do run r comps and race brake pads.

does anyone have any experience or suggestions concerning a non-staggered setup for the z4m? obviously such a setup can help reduce understeer in most cars, but in the z4m, understeer seems pretty easy to dial out just with alignment/suspension setup.

to me, a non-staggered setup reduces track day costs, since being able to rotate the tires evens out the wear a lot.

thanks for anyone's input!
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      08-11-2009, 10:05 PM   #2
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Depends on your suspension, wheel width, offset, race or street tires.

Problem is that with stock wheels and suspension you can't really fit anything much bigger than a 245 on the front and 245 is too small for the rear.

If you get aftermarket wheels you may be able to fit 255 on the front with a lot of work. But 255 is still on the small side for the rear.
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      08-12-2009, 06:03 PM   #3
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Quote:
Originally Posted by silversprint View Post
If you get aftermarket wheels you may be able to fit 255 on the front with a lot of work. But 255 is still on the small side for the rear.
i guess i should have been more specific-- i was not going to try to put non-staggered tires on staggered rims...

from tirerack fitments available, it looks like 17x8.5's with 245's on might do pretty well. to be sure, quite narrower in back, but it doesn't seem like too little tire for a car of this size and weight.

anyone ever tried such a thing at the track?
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      08-13-2009, 05:37 AM   #4
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Hi guys!
I'm going to buy a set of non-staggered 18x8.5's with 235/40 for my '06 Z4 Coupe 3.0si (using 50% at the track and 50% at the city). What do you think of this size?

Sorry for my bad english
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      08-13-2009, 12:34 PM   #5
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I'll likely be going with a set of 18x9's and running 255 all around. If I can fit it, I'll go with 265 all around. The offset will almost certainly be in the high 30's or low 40's all around and then I'll use a 15mm or so spacer in the rear.
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      08-13-2009, 12:36 PM   #6
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I think 245s are going to be too small for the rear, you're going to be oversteering all over the place. 235s, of course, are going to be even worse.

255s would be the smallest I'd go for a non staggered setup, but even then performance will likely suffer.
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      08-13-2009, 01:13 PM   #7
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In my NOT SO HUMBLE opinion, the MZ4 Coupe does not like a non-staggered setup. Unless you can shove 265s or wider up front (you can't without some significant modification) going non-staggered has more drawbacks than rewards.

And while going non-staggered appear to save you a few bucks on tire cost, all it's doing is shifting the cost of replacing 2 tires sooner to replacing 4 tires later...I'm sure if I'm some sort of math wiz, or if I'm REALLY asian, I'd be able to explain to you that over the long haul, your cost is the same between being able to rotate the wheels/tires and replacing them 2 at a time instead of 4 at a time.

The REAL cost saving comes from having the right alignment so your tires wears evenly inside AND out, not front and back. Again, in my NOT SO HUMBLE opinion.
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      08-13-2009, 01:56 PM   #8
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I'm reasonably confident that you can fit a 255 tire up front so long as you have a high 30's or low 40's offset and at least a mild amount of negative camber. With even more negative camber, the kind you'd get from camber plates or knocking out the alignment pin, you could definitely get 265s up front. But I'd seriously recommend getting a high offset up front because it'll allow you to tinker with the fitment by simply adding spacers. My ideal set up would be 265's up front and 285's out back. But that's pushing it in the rear.
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      08-13-2009, 03:54 PM   #9
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What would keep 285s from fitting in the rear? My 275s appear to have plenty of room through full travel.
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      08-13-2009, 06:49 PM   #10
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I think you'd start getting close to the shocks/springs in the rear with a wider tire. Definitely do-able and probably wouldn't require much modification but you'd be toeing a fine line...
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      08-14-2009, 12:47 AM   #11
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Quote:
Originally Posted by The HACK View Post
In my NOT SO HUMBLE opinion, the MZ4 Coupe does not like a non-staggered setup.
what's the basis for your opinion? the stock stagger is similar to the e46 m3, and plenty of people are doing non-staggered wheels/tires for track use in that car.

Quote:
Originally Posted by The HACK View Post
And while going non-staggered appear to save you a few bucks on tire cost, all it's doing is shifting the cost of replacing 2 tires sooner to replacing 4 tires later...I'm sure if I'm some sort of math wiz, or if I'm REALLY asian, I'd be able to explain to you that over the long haul, your cost is the same between being able to rotate the wheels/tires and replacing them 2 at a time instead of 4 at a time.
as a math whiz and an asian, i guess i'd disagree. being able to rotate the tires means that you are more likely to replace the set at the same time, which means less trips to the tire store-- not exactly cost, but convenience to be sure. also, rear tires don't wear on the outer edges nearly as fast as the fronts-- being able to swap tires front to back helps get the most wear out of them.

i do hear you about correct camber and alignment.
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      08-14-2009, 12:50 AM   #12
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Quote:
Originally Posted by JCz04Bimmer View Post
I'll likely be going with a set of 18x9's and running 255 all around. If I can fit it, I'll go with 265 all around. The offset will almost certainly be in the high 30's or low 40's all around and then I'll use a 15mm or so spacer in the rear.
cool-- i'd love to hear how this works out for you.
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      08-14-2009, 12:47 PM   #13
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Quote:
Originally Posted by R32 View Post
what's the basis for your opinion? the stock stagger is similar to the e46 m3, and plenty of people are doing non-staggered wheels/tires for track use in that car.
There's a NIGHT AND DAY difference between the two chassis. What works for E46 M3 does not work for the MZ4 C.

1. MZ4 C is significantly shorter than the E46 M3. 98.3" vs 107.3". 9 inches may not seem like a lot, but it is nearly 10% shorter. Meaning the polar moment of inertia is much easier to overcome in the MZ4 C.

2. MZ4 C is significantly LIGHTER than the E46 M3. 3,250 lbs vs. 3,425 lbs. Almost 200 lbs lighter with the same power and torque means the polar moment of inertia is much easier to overcome in the MZ4 C.

3. MZ4 C suspension is not the same as the E46 M3. The front struts are designs carried over from the E36 M3, which results in slightly less front wheel/tire clearance compared to the E46 M3 (stock for stock).

4. MZ4 C rear ///M variable Limited Slip Differential is "tuned" to send more power to the outside wheel quicker than the ones on the E46 M3, making the MZ4 C's tendency to rotate much quicker.

All factors conspire against non-staggered set-up for the MZ4 C in my opinion. And even with just a 10mm less stagger than stock, my MZ4 C tend to have a little too much squirming in the rear (stock suspension still) in really tight corners. Going squared would mean I would have to be very judicious with my throttle application AND be up on my car control skills much more than I'd like to be.
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      08-14-2009, 01:19 PM   #14
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Quote:
Originally Posted by The HACK View Post
There's a NIGHT AND DAY difference between the two chassis. What works for E46 M3 does not work for the MZ4 C.

1. MZ4 C is significantly shorter than the E46 M3. 98.3" vs 107.3". 9 inches may not seem like a lot, but it is nearly 10% shorter. Meaning the polar moment of inertia is much easier to overcome in the MZ4 C.

2. MZ4 C is significantly LIGHTER than the E46 M3. 3,250 lbs vs. 3,425 lbs. Almost 200 lbs lighter with the same power and torque means the polar moment of inertia is much easier to overcome in the MZ4 C.

3. MZ4 C suspension is not the same as the E46 M3. The front struts are designs carried over from the E36 M3, which results in slightly less front wheel/tire clearance compared to the E46 M3 (stock for stock).

4. MZ4 C rear ///M variable Limited Slip Differential is "tuned" to send more power to the outside wheel quicker than the ones on the E46 M3, making the MZ4 C's tendency to rotate much quicker.

All factors conspire against non-staggered set-up for the MZ4 C in my opinion. And even with just a 10mm less stagger than stock, my MZ4 C tend to have a little too much squirming in the rear (stock suspension still) in really tight corners. Going squared would mean I would have to be very judicious with my throttle application AND be up on my car control skills much more than I'd like to be.
Interesting. I have never driven an E46 M3 around a track but I do find the Z4MC to be quite "squirmy" (as you put it) in tighter corners. Makes sense, now that I'm reading your post.

I may just have to go with a 265F and 285R set up.

What are your thoughts on that? Other than the fact that on the street tram-lining will make me want to take a bus...
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      08-14-2009, 02:17 PM   #15
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I recommend replacing the suspension if you really want to track your car.

I did and now my car handles far better. I use a staggered set-up.
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      08-14-2009, 02:32 PM   #16
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Quote:
Originally Posted by Z4MCJJ View Post
I recommend replacing the suspension if you really want to track your car.

I did and now my car handles far better. I use a staggered set-up.
I plan to but it's always best to learn your car in stock form before springing for a suspension setup. I had a TCK kit on my 330Ci and it was phenomenal. It handed wonderfully and I have no doubt the Z4M would too. But if you're really in to tracking a car, and you get a new one, best advise is to learn to drive it fast stock and then add modifications one at a time. (Suspension is first on my list... after wheels/tires and pads)
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      08-14-2009, 05:22 PM   #17
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Quote:
Originally Posted by JCz04Bimmer View Post
I may just have to go with a 265F and 285R set up.

What are your thoughts on that? Other than the fact that on the street tram-lining will make me want to take a bus...
I'm of the school of thought that wider isn't always better when it comes to tires. The available grip is mainly determined by the frictional material (tire compound) and the size of the contact patch. The size of the contact patch is determined mainly by the mass placed upon the tire and the tire pressure and has little to do with how WIDE the tires are.

The main benefit to wider tires in performance applications, is that there's a bigger surface area to cool-off and therefore the tendency for them to over-heat decreases. There's a couple of argument here, that if you're not on the edge of overheating your tires, you're not driving fast enough. I'm again of the school of thought that if you're overheating your tires, you're not driving SMOOTH enough and therefore you're not driving fast enough.

The other draw-back, is that wider tires are heavier. So if your driving style and your car's weight isn't enough for you to constantly be fighting the tires from overheating, going wider isn't going to help much. On a car like say, the E92 M3, you can put 275+ all around and I will probably still overheat the tires due to the weight and available power. But on a car like, say, a Lotus Exige S, putting anything larger than 255mm would probably mean you're unnecessarily degrading the performance of the car. But that's just my opinion, of course. I don't have actual scientific data to back that up.

However, if you subscribe to "Grassroot Motorsport" magazine, I believe 2 months ago they did an article comparing different width tires on an autocross course on a Mazda Miata, and found that wider tires, up to a certain point, start to degrade their lap time. And about 4 months ago they did an article trying to get a Subaru WRX Wagon to handle 1G or higher with street tires, and when they put on new, wider tires their lateral load readings actually went DOWN.

I can only speak to my personal driving style and experience, and I find that 245F/265R seems to give me more than enough heat dissipation to stave off overwhelming my Toyo R1-Rs, but 225F/255R couldn't save the OEM Contis from nearly melting (when I pulled into the pit, I can put a finger on the tire and it would leave an indentation and the rubber was so malleable that you can almost see my palm print on it).

Then again my 245F/265R combo wasn't enough tires to allow me to keep up with my instructor friend at the California Speedway event. He was driving an E46 M3 shod with 275s all around an otherwise stock car. But that doesn't mean squat since he does have 10+ more years at this than I do.
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      08-14-2009, 06:30 PM   #18
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I agree with The Hack.

Yes. Please learn your car stock....but if you want it to really track well then upgrade the suspension.
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      08-14-2009, 11:46 PM   #19
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Quote:
Originally Posted by The HACK View Post
There's a NIGHT AND DAY difference between the two chassis. What works for E46 M3 does not work for the MZ4 C.
one of the most informative posts i have read on a car forum in a long time. thanks, hack!

of course, all of these points (except for the tighter space in the front) are great reasons to have the mcoupe over the m3.

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      08-15-2009, 11:54 PM   #20
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Quote:
Originally Posted by JCz04Bimmer View Post
Interesting. I have never driven an E46 M3 around a track but I do find the Z4MC to be quite "squirmy" (as you put it) in tighter corners. Makes sense, now that I'm reading your post.

I may just have to go with a 265F and 285R set up.

What are your thoughts on that? Other than the fact that on the street tram-lining will make me want to take a bus...

265/285 won't fit with stock suspension. I doubt they will even fit with aftermarket wheels.

On the rear a 275 barely fits. Anything larger will rub the chassis on the inside. They will burn thru the fender liners on the inside and after that start eating the chassis. This is with moderate camber and some toe IN. If you move the tires out with a lower offset it will rub the fender. The only way is to raise the car to ugly high SUV height so it doesn't rub.

A 245 is about the largest you can go before it starts to rub the stock spring perch on the front. A wider tires is not only wider its' also taller. With aftermarket coilovers that have narrower springs you make be able to squeeze 255s.

I agree with Hack. Don't put wider tires on the car unless you have maximized the grip of a smaller size and you still need a wider size. Alignment, proper tire pressure, and sticky compound will give you a better handling car than putting oversized tires on the car that wont' fit right and make you run suboptimal alignment.
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      08-16-2009, 01:56 AM   #21
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Great read thanks to the Hack.

I'm up in the air on wheels for the track for my Z4M. I've tracked my modified E46 quite a bit with 245/275 on it and modified suspension. My Z4M has full TCK setup with camber maxed out on 235/265 on the street, it definitely feels a bit more skirmish than E46. I'd prefer a bit more grip but don' want to go overboard, right now I'm thinking 245/40/18 and 275/35/18 NT01s might be the ticket. Thoughts or experiance with this size / setup?

I've found quality 18" wheels even more challenging to find as well, most used E46 setups are square or the wrong offset, the TR Motorsports MT1s from Tirerack are a great option but the 10" rears are constantly on back order.
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      08-16-2009, 12:14 PM   #22
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Great info on all fronts. Thanks.
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