Mark R.

I did a bunch of searching by could not find this specific info...

Is anyone running 9" wide front wheels with a 60mm offset..?
If so, what has been your experience (& with what size tires)?

On my other car, I currently have 8" wide with 59mm offsets.
They track well and everything clears (with 235/40-ZR18 tires).

So the centerline of these wheels would remain in the same place.
But the wheel width would grow by 0.5 inch inward and outward.

Thanks in advance for any feedback...

mark kibort

a perfect fit with 275s up front on a 9.5" back spaced 8.5" is known.
that's a 85mm offset , 60mm offset , means that the wheel is pushed out .5".... you would be lucky to make a 245 fit up front, but I bet its close.

SMTCapeCod

I've got 245s very comfortably on the Cup II 17x8 ET70. It's conservative, there is more room available but the wheel width is limiting, depending on preferences.

I wanted to test fit my 993 wheels 16x9 ET70 an my Euro, but given tire selection probably won't bother. Could be interesting to put em at 4 corners if I did auto-x regularly. Don't recall constraints but the may not clear later brakes.

Red Flash

This is a topic I am also interested in digging into.

Mark K., I don't exactly understand your comment about pushed out 0.5". 0.5" from what?

My favored combination would be 245s on 9" rims all around.

mark kibort

perfect fit, is the 85mm offset.... that's a 8" backspacing on a 9.5" rim.
a 70 will work, but that puts the tire 10mm further out.( about .5") no prob for a 255 tire. a 9" rim will want a 7.5" backspace to keep that outer edge the same.

996 rims don't work, tried that already.. rim is way out side the fender.

hacker-pschorr

Tires can vary greatly from different manufacturers. I've seen up to a full 1" different in width between tires of the same rated size.

A few years ago a friend of mine went from Goodyears to Yokohamas on his Corvette. Same "size" tire but the Yoko's did not fit, they rubbed the fender and the Goodyears did not.

AO

You clearly understand the dynamics at work. WHile I don't have direct experience with the dimensions you are inquiring about, I think it will be VERY close and will largely come down to which tire you choose to run.

Since your offset would remain roughly the same, yet your outward dimension would increase 0.5" (12.7mm), that's akin to running your current 8" wheel with a 47mm offset. The general rule of thumb is to go no less than 50mm.

You could try a 13mm spacer on your current wheel to see if it would fit. THen see if it rubs. Unfortunately the front requires time and distance to settle, otherwise I would suggest using a stack of fender washers as a cheap temp spacer. I did that on the rear of my car and it worked great, but I would never do it on the front.

As Hacker mentioned, the tires can have a huge impact on overall actual width, but the cars themselves can vary a few mm one way or the other.

My guess is if you can get them to fit, they will rub on full turn. Highway driving will probably be fine.

Gary Knox

I have 9" fronts with et 69.05 and 255/35 X18 tires on my '94 (custom built OE Porsche Sport Design two piece wheels). No rubbing on the outside (fender lip factory rolled), but when steering wheel is turned to full lock, there is a slight bit of rubbing on the front inside of the wheel taking the larger diameter turn at the wheel well liner.

I also have a set of 17" X 8" et 70 cup II wheels for the front of the car. There is no rubbing anywhere with these wheels.

FredR

Mark hit the nail on the head- with that offset the widest you will fit will be a 245 -you will be losing some NSR but not as bad as many other wheels.

I find the dialogue about different tires being different dimensionally interesting- I have used Michelin PS2, Michelin Cup, Pirelli and currently Continental and found no difference whosoever in the way they fit but they are all top quality tires. I rather suspect the differences may come with the "bargain basement" cheaper tires but I can only comment on what I have experienced. I suspect that some of the cheaper tires use more rubber to compensate for lesser structural designs [more weight/unsprung mass?]. There is a lot of engineering in performance tires- I dare say cheap ones weigh more. I once tried a cheaper make becuase htere was nothing available at the time- used them once and gave them away to Musang driver [poor sod!]- I found my stock GTS wheels with a wider than stock 235 section Michelin PS2 easily outperformed those crap ones on my big wheels!

The ideal front wheel as I am concerned is a 68mm offset with a 9.5 inch rim. With the fenders rolled it takes a 265 x35 section perfectly but you need an additional spacer each side of the steering rack to limit the lock at bit and avoid rub on the sway bar [I use the Devek bar and I understand that is a little more lock limiting than the std roll bar. Gary's comment in this regard [with a 255 front section] was interesting. I might have thought the extra 5mm clearance would spare him from any rubbing issue but clearly not.

With a 295 rear section and the roll bar set to full hard I find the handling is pretty neutral with a slight tendency to oversteer, soften the bar and its *** is all over the place quite easy such is the fierceness of the front grip. With 2 degrees front camber and Carl's lower front strut brace and a custom stainless steel top brace the car can pull about 1.2g lateral acceleration and at that point my chicken switch kicks in - the front tires are not even complaining! The downside of the camber is you lose some straight line braking [I think] but with those tires, Hawk plus pads and GTS brakes it still stops very rapidly from high speeds.

When looking for bigger front wheels an often overlooked variable is the need to clear the front calipers- offset alone does not guarantee this and you need to ensure the wheel design has an appropriate spoke curvature profile. I have to be very careful when mounting my front wheels not to get my fingers trapped between the spokes and calipers- there is not a lot of clearance on my wheels.

Trust the above helpful

Regards

Fred

hacker-pschorr

I had a Bridgestone, BF Goodrich, and a Dunlop all 275/40-17 to test fit on my replica Cobra. The width varied by 1/2" between the three.

If you check the "gird" of any tire size, you can see the section width is not the same across all the brands.

Then you add in things like lip protectors, which were a problem with the Continentals I once had on my 79 vs the Michelins on there now.

You won't notice anything unless you are on the bleeding edge of what will fit without rubbing. Two of my cars are at this limit and I have to be very careful what I fit on them.

AO

Hard to find... I believe Kenesis made one. Not sure who else.

FBIII

When looking for bigger front wheels an often overlooked variable is the need to clear the front calipers- offset alone does not guarantee this and you need to ensure the wheel design has an appropriate spoke curvature profile. I have to be very careful when mounting my front wheels not to get my fingers trapped between the spokes and calipers- there is not a lot of clearance on my wheels.

+1
I'm going to use some 10 x 18 et 65 Porsche wheels on the front of my Euro and I had to shave some aluminum from the calipers to clear the spokes.

FredR

Hacker,

Fully agree- on my setup the side wall is the critical element -the junkers I tried rubbed on the Devek bar at full lock even with the additional spacer in the rack- the "good ones" do not- but it is close. The Conti's do have better rim protection than Pirelli- one of my Cayenne wheels can attest to that [sad to say- a bit of light curb rash].

Rgds

fred

FredR

Andrew,

In this market you are into custom 3 piece forged wheels at whatever the going rate is these days [it used to be around $5k or so].

Not a cheap option but a complete gamechanger in terms of handling. Stock 928 front wheels are simply way too under tyred for the capability of the 928- your granny could understeer a stock S4 no problem.

Rgds

Fred

The Forgotten On

I figured that out the hard way. I would be way more worried about the front letting go than the rear. Putting more tire in the front is the best performance improvement you can make per $ spent.

245's seem to be the limit without fender rolling and they make the car handle so much better and it just feels safer as the grip limit is much higher when using a nice set of tires.

I run et59 8 inch (Panamera) rims with 245's on my 81. It rubs a little when you go over bumps hard but later years should have no problem with rubbing, Especially if you fit 235's on them like others have.

Good luck with whatever choice you make as now it will be an informed one after all of the comments on this thread.