[Lonestar968]

Thinking seriously about an upgrade to 9x18 fronts and 11x18 rears. I think Flash has the lowdown on the fronts, yes? But who (Matti?) has the mysterious 11x18's installed out back? [img]style_emoticons/<#EMO_DIR#>/dry.gif[/img]

What I'm after is offset numbers if you've got 'em. Thanx!

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[flash]

11s will require a rock stiff suspension and solid bushings - any lateral movement and you'll hit

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[PorscheDude]

I've seen 11's on a 951 turbo S.
Takes some work. I think the ET was around 70. Need a little inner fender massaging.
On the 968 you may need a fender roll and some neg camber.
I think it can be done, but your gonna have to nail the offset.

If you want I'll ask the guy what the final offset was.
BTW this a track car with LS swap.

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[Lonestar968]

Flash: On a street car, how much lateral movement is typically experienced? Heck for that matter, how much on a street/race or just plain track car??? How much flex in Delrin or similar bushings??? This is interesting stuff! [img]style_emoticons/<#EMO_DIR#>/smile.gif[/img]

Dude: I'd be interested in whatever numbers and info you can provide.

I really hope to see if somebody's already done the homework/mock-up/test-fit just to save a few bucks and some time. There are a lot of great (garage) racers out there who have probably tried this stunt before.

I understand the suspension geometry is a factor with interference as are the wheel openings and such. I'm not all "Joe wheel engineer" or "Jimmy race car driver" or anything like that, I just want to see if I can fit some fat ass tires under the car and still be able to drive it. You remember, like back in the day... something like what you probably had under your '66 Mustang or '69 Camaro!!! Remember how cool L60x15's looked back then?!! [img]style_emoticons/<#EMO_DIR#>/cool.gif[/img]

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[PorscheDude]

I'll see what I can find.
I did have 18x10 with 285/30's at one time. Plenty of clearance.
Unless you plan to run a 305 or 315, a 10" or 10.5" would suffice.
You might want to run 9" fronts with such wide rears.

Check Tony Garcia's 951 page. I think he had some custom cup wheel taken out to 11".

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[Lonestar968]

How wide a tire will fit on a 10" wheel at about a 54mm offset and not rub the inner lip?

I'd love to run 9" fronts (I believe Flash has them on his car, yes?), but what offset?

Do you know if there are any rear suspension differences between 968 and late 944/951? Perhaps alignment settings might be different or something? Or maybe the 944/951's had more room in the wheel well to begin with?

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[PorscheDude]

The suspension, fender arches and pan are the same between both.
I know the 951S had rolled fenders from the factory, not sure about the 968.
I think I've seen some guys running 10's in the front with 255's or 265's.

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[PorscheDude]

Check the link on the bottom left of this page
http://www.tonygarcia.org/

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[PorscheDude]

Pic of 17x11 cup wheel.
http://www.tonygarcia.org/944V8/4/DSC05613.JPG
looks like he is running these on all 4 cornors.

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[PorscheDude]

I just spok with Tony, to get 11" fronts he is using 1" wider fenders. That makes it "easy".
The rear fenders were rolled very aggressivly with 2 1/2• neg camber.
He was not sure of the rear offset, but seems to think they are still around -55mm

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[Lonestar968]

Wow, that sounds like way too much thought just for fat tires. Better sleep on it. I might just have to settle for the 10" wheels and call it a day.

With that said, how fat can I go on a 10" wheel in back without sidewall distortion?

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[PorscheDude]

285/30 they fit nice.
Here's 18x10 with 285/30 and 18x8 with 235/45
I'm not 100% sure on front tire size in this pic, but positive on the rear.

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[flash]

it is a lot of work to get an 11 under there - also, unless you have the power to turn them, you probably won't be happy with the result - the resistance increase is significant

i also have a 285/30 on my 10s - haven't had them shake loose yet

i do indeed have 9s on the front - on them is a 255/35

not sure i would do it again though without M030 hubs and spindles - i am really worried about the increased stresses on the suspension - more tire means more adhesion, which means more load on the components - i won't be pushing this car hard on the track until i change out the hubs and spindles - the only reason i am not totally freaked out is that i have seriously upgraded the suspension, including some VERY large sway bars - this flattened the car out, and transferred a lot of load to the inner wheels, and off of the weaker stock hubs and spindles

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[duke]

I have 11" rear wheels on my 951S -88, ET 65.
But with -3 deg camber I can actually use a 18mm spacer to maximize the track width.

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[Lonestar968]

Thanx for all of the great input everyone! And especially thanks for the heads-up on the spindle stress factors, Flash. I do want to track/DE my car once in a while so avoiding unnecessary repair expenses as an afterthought, or track specific ($$$) upgrades as a forethought, are points very well taken.

Seems like the bang-for-the-buck ratio doesn't warrant 11's. At least not yet (how the heck do the 944 guys do it???).

And it also seems like the general consensus is to stick with 10" wheels with 285x30 tires for the fattest yet manageable profile. That'll have to do. At least for now. I still want to add a tunable suspension one of these days and it seems logical to think lowering the car will only exacerbate the interference issue. Hmmm... I remember someone in another post talking about losing the torsion bar housings et al since they're already running coil-overs. Perhaps someone (uh hem...) will feel compelled to design a new, improved trailing arm that will allow wider wheels without interference or suspension compromises. Just throwin' it out there people. Just throwin' it out there.

Conversely, if the SC kit yields the necessary power/tq required to offset the additional drag/rolling resistance, maybe 11's aren't completely off the radar screen quite yet. And if "all" it takes is a set of M030 spindles to safely hang 9's out front, the dream is still alive!

Dream like you'll live forever... [img]style_emoticons/<#EMO_DIR#>/cool.gif[/img]

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[flash]

one thing to make absolutely certain of is that you stick with VERY light wheels - a rear 18x10 at more than 24lbs will cause you problems with the factory torsion bar rate - remember, the tires get very heavy in large sizes - that mass has to be controlled by the shock, which is also trying to slow down the spring

the problem with 11s is complicated

it is not technically the trailing arm, though that is a component of the issue - it's the 2 point design - if there were upper and lower unequal length arms, it would help

the problem is the amount of travel of the rear suspension, the camber angle, and the curvature of the quarterpanel - they add up to complications

i have REALLY large sway bars - this prevents to roll that causes camber change

i also have lower bracing, which helps prevent camber change up front, allowing me the room and not having to run large camber angles

i also have stiffer springs, which limit travel, taking some of the curvature out of the equation

it all adds up

as for designing a new rear suspension, i think i'm pretty happy with what i have going on, so that one is likely to be somebody else's baby - as it stands, i can't shake the rear loose on the street without a lot of effort or a big mistake - on the track, it's very controllable

my setup wasn't cheap, but it works well - staying away from gas struts and shocks was the key

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[firefish]

Flash, how fat are your sways? Like the Tarret or meaner?

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[flash]

meaner

31.75mm hollow front - delrin bushings - heim joint end links
22.25mm solid rear - grease fitted polyurethane bushings - currently OEM end links

these will NOT work unless you brace the bottom of the car AND run stiffer springs all around

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[333pg333]

255/9 and 285/10s should fit comfortably. I have these on 951s. I also had the front guards trimmed and fitted 10" Enkeis all round for the track. Hoosier 285 on the fronts, 295 rears. There is room in the back for larger, but like Flash says, you need to upgrade your componentry before doing this. In reality if you're just going to DE the car then you don't need crazy wide such as Tony G runs. If you are going with a Supercharger then perhaps you're upgrading suspension / hardware anyway? If so, what to?

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[333pg333]

Bob, just curious what suspension and springs you're running with those sways? They are large. Looking at the POV that sways are used as more of a fine tuning device, I assume you don't quite agree on this? I have run my Tarrets on full hard and loved the flat feeling, but it didn't reflect in my track times. Also of course there is always the line where you start to lose traction with too much loss of roll. I have to assume you drive on pretty nice surfaces most of the time.

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