Max width of tires on a Non M Z3?

[z3papa]

In your experience, have you found that 245 width tires on a 17x9 et30 wheel have the potential to clear up front without going too aggressive on camber?

Yes although I am running coil overs. My recollection is stock springs sit above the wheel height which should allow 245's to be an easy fit. To illustrate my point, the signature pic which I know is very poor, shows stock Style 32 rears 17x8.5 with an 41ET and 255's up front.

[kornfeld]

Which coilovers are you running, and do they leave more room for wider wheels, or less (as compared to the stock set up)?

[z3papa]

Which coilovers are you running, and do they leave more room for wider wheels, or less (as compared to the stock set up)?

I was running AST 4200's in that picture but now have a stock M roadster suspension on the car. Coilovers tend to run 2.25", 60mm or 2.5" diameter springs which are smaller in diameter than stock, but longer, whereas the stock position allows for a 25" tire diameter (17's and 18's wheels can fit if the tire is no taller than 25") without having any interference with the strut as the lower spring perch sits higher than that.

[BenFenner]

I spoke with a rep at Apex just to get their input on things. He sounded iffy about the 17x9 et30 fitting at all. Is that just them being conservative, given that they actually sell the wheels and probably don't want to have anyone stuck with the tires rubbing at all?

It is iffy, but it can work without any special treatment. I'm running them right now with 245 wide tires that are known to run wide. (Recall the 6-cylinder non-M has identical front suspension and fenders to the Ms.)

[kornfeld]

I was looking back at your thread that's linked in your signature, Ben, and are you still running Sumitomo HTR ZII tires? And according to this post:

http://www.bimmerforums.com/forum/sh...1#post27934131

You're running (or at least you were running at that point) this suspension...I think:

http://www.tcklineracing.com/webdocs...Details136.cfm

Is that all correct?

And the pictures I found in your thread all were of your car on roadstars (which I think are 17x7.5 et41 up front)...can you point me toward a picture of your car with the 17x9 et30 wheels up front? Or do I have the roadstar specs wrong?

[BenFenner]

kornfeld, I'm a year behind in updates on my build thread. I've been making a hard push to get it more current, but the pictures of the ARC-8 wheels haven't been put up yet. =(
I also don't have reliable access to my images right now, otherwise I'd commit to uploading some tonight for you. When I can, I will.

The suspension I have right now is the same as what your research uncovered with one exception. The link you posted is the non-M kit, and I have the equivalent kit for an M.


My current setup:

Front:
Concave ARC-8 in 17x9 ET30 fitment. Tires are Dunlop Direzza ZII in size 245/40/17.
The wheel is exactly flush with the fender as best I can tell from top to bottom (I have very little camber up front). The tire with its rim protector stands proud of the wheel and the fender some 10mm at rest. The tread is not as wide as the rim protector, so it is maybe 5mm proud of the wheel and fender at rest. During compression, the tire cambers in some and clears the metal fender just fine. It hits the inside plastic wheel well guard (as I explained earlier) only during highly loaded turning maneuvers with decent bumps in the road mid-turn.

Rear (much less relevant to you unless you know the difference between M and non-M brake rotor spacial placement which I don't off the top of my head).
Concave ARC-8 in 17x10.5 ET27 fitment. Tires are Sumitomo HTR-ZII in size 275/40/17.
These tires are stretched much more than I'd like on this tire. I wanted 295s, but could not find suitable options at the time.
I have rolled my rear fenders, and had at least 27mm of gap between tire and fender. I installed a 20mm spacer which helped a lot (netting an effective ET07 fitment) but I still have more gap than I'd like out back. I have a new set of wheels coming, so all of this is a bit moot for me now.

[kornfeld]

Awesome. This is obviously going to be not-entirely-applicable to my situation because I'll be in a non-M, but how do you feel that suspension kit compares to the stock suspension? I would like to lower the car a bit, but I also want to keep the car from becoming a jarring mess.

[BenFenner]

It's been so long since I've been in a stock suspension Z3 that I can't recall what they are like in stock form. One of my goals was to get out of my knife-edged SE-R and into a daily that would perform as well on the track but also not embarrass me or provide a jarring ride since the wife and I car-pool daily.
When I first got my coupe it had a full E36 kit on it (which have the wrong length rear shocks) which made it horrible to ride in. I've since replaced with the correct rear shocks, and just assume the rear springs are comparable.

Long story short, the coupe still crashes quite badly over most road imperfections even on the softest damper settings (front and rear suspension) that other cars just soak up. My SE-R has better manners than my coupe in this regard, which is sad. One day I will get around to fitting a suspension that performs well in most areas. I have the OEM stuff if I want to go back, but I don't because the improved ride height and feedback is apparently much more important to me than the comfort even still. From my experience, I wouldn't recommend this base TCK kit if you want to avoid a jarring ride.

It's odd, because my previous experience with a budget E30 suspension upgrade went so well it convinced me that BMW modders must demand a lot from their kits. It dropped the car a staggering amount but kept the ride as good or better than stock. I was expecting something like that from this kit, but I did not get it.

[kornfeld]

Cool. I definitely don't want to have a harsh car...I'm hoping there is an option available to lower the car for cosmetic reasons, but keep it pleasant as a non-track car. I'm reading up on suspension options in other threads, so I guess I should move that topic over to those places, such as these threads:

http://www.bimmerforums.com/forum/sh...recommendation!

http://www.bimmerfest.com/forums/sho...d.php?t=172154

[BenFenner]

I uploaded these just now for you.

https://i.imgur.com/xoBJ67M.jpg
https://i.imgur.com/HJ12NgB.jpg
https://i.imgur.com/VRGkNiO.jpg (money shot)
https://i.imgur.com/imAkU56.jpg
https://i.imgur.com/fdTG8EO.jpg
https://i.imgur.com/eKVNhC8.jpg

http://www.bimmerforums.com/forum/sh...recommendation

Good, you'll find more detail from me in there, and I'd love to contribute more to that thread if it can help you. (I believe the TSK base kits come with springs too weak for the drop. The higher spring rate is likely the main reason most people say the TCK racing kits ride much, much better. Either that, or the base Koni damper has really stiff high-speed compression which causes the jarring.)


Money shot:

[Tim95M3]

Just wanted to chime in here and say thanks for the good info guys. I have a 98 2.8 that i'm looking into coilover setups for, and I really wanted a set of concave ARC-8's, but apex told me there's no way to fit them up front.. Guess they were wrong. I have a TCK S/A kit on my E36 with 450/500 springs and I like the way it rides.. Just wondering if those spring rates would also be ok for the Zed? Any input is appreciated..

[Russellr.1]

9x19 rear
8.5x19 front

Fronts rub on big bumps. I am thinking 18's would be ideal.

[BenFenner]

I have a TCK S/A kit on my E36 with 450/500 springs and I like the way it rides.. Just wondering if those spring rates would also be ok for the Zed?

Try here:
http://www.bimmerforums.com/forum/sh...e-spring-rates
http://www.bimmerforums.com/forum/sh...normal-chassis
http://e30m3project.com/e30m3perform...e/eff_rate.htm *

And you might be interested in this tidbit from the second link:

Wow. Just saw the spring rates for the Dinan E36 M3 springs... 100# Front / 425# Rear...

[Z3speed4me]

Since my coupe was posted....

TCK S/A kit on my coupe with 450/500 (same as the last car)
About 3 threads from bottom
Handles better than stock, not even comparable; I have adjustment one half turn from full hard and still better than stock, granted my oem shocks had 90k on them
Tires are 235/45 front, 245 would probably fit ok, maybe rub on the outer fender liner, they fit fine but no idea how much more space I actually have. 275/40 rear (wish I could find wider that's not a race tire). 9" front ET 30, basically perfect; 10.5" rear et 27, with 12mm spacer, a 15 would be better.

I have yet to see any coilovers on these cars that will eat up road imperfections like "newer" cars will, I just run over stuff in my R that I'd hate to hit in my coupe. But they are still an improvement over the stock setup in every way.

[kornfeld]

Awesome, glad more people are jumping in here. Ben--those are the exact pictures I was hoping to see. Man do those wheel suit these cars.


I posted up a question in the suspension thread I linked to:

http://www.bimmerforums.com/forum/sh...ndation!/page2

And would love some input there as well.

- - - Updated - - -

Ben and Z3speed4me, do you have the front camber plates on your car along with your suspension kit?

[Tim95M3]

So I know the 17x10.5 ET 27 probably wouldn't fit the non-M rear axle... Or would it? Or the 17x10 ET 25.. Or the 17x9.5 ET 35. Basically I want to keep a staggered setup, and have as wide/aggressive as I can in the rear. Hard to figure out since most are M cars here..

[BenFenner]

Tim95M3, like you I wanted as aggressive as I could get all-around. However, I wanted to stick with the 17" wheel diameter. So, when it came time to find tires for the rear, it became obvious I was going to have to compromise. There are almost no options for 285, 295, or 305 tires. This means you're stuck with 275 or 315 as options. If you want to go to 315, then by all means, go for it. However, I could not justify a 315 tire, so I went with the 275 on my 10.5" wide rears. This is way more stretched than I wanted. Given the available tire sizes right now, I'd prefer to be in a 10" or maybe even a 9.5" wide wheel out back. I say this because you're likely to find the 17x9.5 ET35 wheel to be near the sweet spot for your non-M car, and a really attractive option.

Bottom line, look at tire options before settling on a rear wheel size.

[Tim95M3]

Thanks for the help. I definitely won't go any bigger than 17", I think anything bigger looks ridiculous on the Z. Ideally I was looking for a 245 or 255 and 275 rear stagger. I think I might end up going the 17x9 17x9.5 route. Too bad ARC's are on back-order right now.. :\

[BenFenner]

That sounds like a good plan to me. 245/275 with 9/9.5 seems like the way to go in your case considering the offsets. It'd be nice to go 255 up front but with the 9" ARC-8 offset of ET30 that is a tough call. It might also be nice to do 10" out back but you'd have to roll your rear fenders probably, and be millimeter accurate.

[Tim95M3]

Indeed. I'd love to fit a 10" rear but not sure on offsets.. I really want to keep away from rolling or any sort of body modification as this car is immaculate and I really don't want to hack it up. Just want a nice aggressive look with little hassle. Thanks again for your help.

[danomite]

So I know the 17x10.5 ET 27 probably wouldn't fit the non-M rear axle... Or would it? Or the 17x10 ET 25.. Or the 17x9.5 ET 35. Basically I want to keep a staggered setup, and have as wide/aggressive as I can in the rear. Hard to figure out since most are M cars here..

Tim: See my last post which includes my current APEX set-up. I'm non-M, and running 10.5 ET27 rears.

[BenFenner]

Tim: See my last post which includes my current APEX set-up. I'm non-M, and running 10.5 ET27 rears.

Ride height? And how do you think it would fit without rolling those rear fenders?

[Tim95M3]

Tim: See my last post which includes my current APEX set-up. I'm non-M, and running 10.5 ET27 rears.

Ride height? And how do you think it would fit without rolling those rear fenders?

Also curious about not rolling fenders with that fitment. Do you have any pics of the setup?

[danomite]

Don't know the exact ride height, but you can see it in my sig...it's low! As for fender-rollage....why wouldn't you want to roll your fenders, if running max width is your goal? Fender rolling should be a given...it's one of the simplest mods you can do to your car, and is key to achieving max width. This set-up probably wouldn't work with 0.5"-0.75" of flat metal facing inward perpendicular to the tire sidewall. Although, if you wanted to run some narrower tires and stretch a little, then it would probably be fine. Remember though, tire manufacturer's given widths are not all the same. The Hankooks tend to run wider than most other tire brands per given measurement.

I researched like crazy, took the measurements a bazillion times, and did the math over and over again to be absolutely sure that these would fit like a glove...and I nailed it!

I'll get some close-ups and in-line pics when my car gets back from its makeover.

[Sky1Z3]

Don't know the exact ride height, but you can see it in my sig...it's low! As for fender-rollage....why wouldn't you want to roll your fenders, if running max width is your goal? Fender rolling should be a given...it's one of the simplest mods you can do to your car, and is key to achieving max width. This set-up probably wouldn't work with 0.5"-0.75" of flat metal facing inward perpendicular to the tire sidewall. Although, if you wanted to run some narrower tires and stretch a little, then it would probably be fine. Remember though, tire manufacturer's given widths are not all the same. The Hankooks tend to run wider than most other tire brands per given measurement.

I researched like crazy, took the measurements a bazillion times, and did the math over and over again to be absolutely sure that these would fit like a glove...and I nailed it!

I'll get some close-ups and in-line pics when my car gets back from its makeover.

What rear camber are you running to fit those? im on 18x10ET43s with 285 and its perfectly flush. -2 deg rear camber. to fit 10.5 et 27 you have to be seriously cambered.