tommi nylund

Hello.

I know this might be a title discussed many times before, but didn't find anything helpful by search...

So, what offset I would need to use 10" x 18" wheels at front of the stock S4, possibly without modifications? 11" ET45 rear wheel didn't fit, I tried.

Rubber would be 265/35 or 255/35 maybe?

Thank you!

Gary Knox

tommi,

I have 9" et 70 wheels on the front of my '94 with 255/35 Michelin PS2 tires. No rubbing, the slip angle seems to be good, as there is no slipping on a wet surface during sharp turns. I don't really know whether a 10" would fit, but I'd think you'd need at least an offset of ~80mm or even more. THAT's hard to find.

My fronts are a custom made set of the 996/Boxster Sport Design 2 piece wheels (by BBS). I used the spider from a pair of 7.5" wide fronts (et 50), and the 9" wide barrel from the boxster rear. This combination results in an added 1/2 inches of rim on the inside of the centerline, with no increase from the 7.5" spider on the outside. That's how you get the et 70 (actually, I think it's 69.5!)They look and function wonderfully - in my opinion. I have the 10" et 65 Sport Deisgn wheels on the rear with 295/30 tires.

Gary Knox

Brett928S2

Hi

On a STANDARD S4 , its not going to work, 10s are too wide....

Rolling the arches may make it possible but I doubt it....and its going to "tramline" very very badly...

Mine are 18/7.5 with a 5 mm spacer from a GT3 on 225/40/18 rubber and thats as big as I can go although mine is an S2.

All the best Brett

mark kibort

10s work perfect. No tramiling or any ill effects . in fact, I also have 10s with two sets of rims, now with two different offsets. they work fin, but you NEED to have a 8.5" backspacing. Like the 8" backspacing for a 9.5" rim, which was the standard for the last 10 years for 9.5s on stock chassis. I run 275s, which ONLY require a roll of the lip, absolutely no fender damage or stretching, just a roll. a 255 up front will require no mods.

8.5" backspacing on the 10" rim. no issues. never! perfect. and, certainly no driving issues at all.

Ive done this on S2s, S3s and S4s

rear 11" rims have to be 8" backspacing to fit as well, although 7.5" might work with some rolling as well. very very slight. again, just the lip on the inside.

mk

VT928

Tommi,

I run a 17*9.5 inch rim with 60mm offset and 255/40 tires on the front of my 1980 Euro S. They do not rub and requred no modification to the front fenders. I did have to add a second rack bumper to each side of the rack to keep the tires frpm rubbbing on the inside of the fender at full lock. My car is at the low limit of the factory ride height and I think that I will go to 265's the next time I replace front rubber. I am sure that they will fit easily. The impact the larger rubber on turn in and braking is very significant and all good. It is my opinion that the 928 is significantly under tired on the front when a 225 tire is used.

Paul !980 Euro S Red/Blk Lea

tommi nylund

Thank you for the replies! Especially Mark, because I remember you have used quite wide front wheels, but didn't know the offsets....so it's something like ET70 for 10" wide front wheels? So you have successfully rolled front fender lips without cracking?

I agree with you Paul, completely. 225's at front look absolutely too narrow for 928, specially if have something like 11" wide at rear. And I was also thinking about the weight distribution and I came into same conclusion that 255-275 would be much much better choice for front wheels when thinking about cornering & braking. But then they need at least 9.5" wide wheels...

I found out that there are 10" wide ET65 996 hollow spokes available which would be perfect replacement for me, but they have too little backspacing? And I don't think they can be machined to fit. Is that correct? The 11" ET45 wheels I have at rear cannot be machined any more than just 2-3mm's, it just looks too thin under the wheel nut cones....I think...

stuartph

Tommi

The 10" ET 65's fit with no problems, they are not the best but they work fine

hacker-pschorr

Rick Carter has 10" et65's on the front with 265 tires.

Jim Page (local Green Bay 928 guru) has 305's on the front of his S4. No body mods other than rolled fender lip. He's also using an OB upper control arm to pull in the camber a bit.

I'm not sure the rim size, I'm guessing 10" - custom Fikse wheels

That is correct.

Few yeas ago I started measuring the thickness of the mating surface of any wheel I came across. Everything from Ferrari, Porsche, VW's, Audi's, SAAB etc... If I saw a wheel off the car i would measure it.

Every wheel had less than 1/2" (12.7mm) of "meat" between the hub face and lug nut.

mark kibort

No problem. Yep, been through a lot of chassis and fenders and have learned what works and what can work , with some work.

Rolling up front is done with a baseball bat. usually with the wide wheels and tires. you have to start slowely and slowly pin back that lip. no cracking, even with real street cars with nice paint. mine turned out fantastic, even doing so hard that I got that lip pinned back as far as possible and a slight stretch of the fender radius. it took that to get the 305s up front., but to work on a street car, you could do it withouth the major fender mod I made. (pulling out the structure) (because the tire wont go so high up the fender when you are on the street vs racing, PLUS, my car is a lot lower, in the 110mm range, so that is also an issue as well. camber is only 1.6 degrees which also helps, but with 1 degree, it might be a problem. with a 275 or 255 up front, you will have all sorts of room.

I would say, 8" backspacing on a 9.5" rim is near 85mm offset . with a 10" rim you can get much more backspacing but then you risk the chance of the tire hitting the chassis or swaybar under full lock. 10" rims with 8.5" backspacing seems to be the absolute sweet spot. dont know the offset, but Im sure you can find how to figure that out.

Mk

tommi nylund

Thanks guys for an excellent information!

It is good to know that I can roll the front fenders as well if needed...with patience and care.

8.5" backspacing for 10" wheel will result ET76.1 if not mistaken. And it cannot be achieved with any other than special order wheels, I think? (or by modifying wheel, brake disc and/or wheel hub assembly)

10" wheel with ET65 will however result 8.06" backspace...but if wheels with those dimensions fit Rick Carter's car, they must fit mine car also! So I have to start hunting for a pair of those wheels....

So the OB upper control arm will give more negative camber? How much can you have without excessive tire wear? Mark wrote he has 1.6deg (which can be dialed in with S4 upper arms?), but is it too much to get for street car?

I think I will be getting the sway bars from 928 Specialists, so hitting front sway I think is not a problem...maybe. And no, my car will never be 110mm low when driving streets!

Wow, 305's up front!?! They must give the car a phenomenal front end grip?!

mark kibort

Actually, I have a set of 10" wheels up front with 8" backspacing too! however, I have to see if they are gong to work with the 315 or 305s. they work with the 275s, but the fenders are pulled out. however with a 255, they would work. the plan is to run only 305 or 305 up front.

actually, the grip is not that different. more firmly planted, the push is removed, but the lap times are not that different, maybe 1 second, but thats mainly due to hoosier vs toyo of the two tires, run on the same day, same track. I do like the 305, as it does raise up the ride height slightly.

mk

Lizard928

I just ran my 18x11 for all 4 corners (roughly a 79.8mm offset) w/ slicks yesterday.

I would not recommend that for the street though, reduced turning radius, slight amount of rubbing on the front too.

You really need to run a coil over setup in the front (with 2.25 or 2.5" ID racing springs), to be able to clear the high offset wheel.
You will also need to add spacers to the rack to prevent the tire from hitting your frame rail, or swaybar as the turning radius will be reduced.

F451

Running this exact setup on my '88 S4 front end, no fender rolling, no problems.

FredR

Tommi,

Before getting too carried away with numbers suggest you heed Mark's wise warning about going too wide on a street car [if that is your intent]. For street based cars a 265 section up front will give you phenomenal grip if you have the right tires and the optimal set up, indeed a 255 will be more than adequate for most- the difference between stock and these wheels in this range is mega.

For a 265 section a 9.5 inch rim works fine for me with ET68 and they will also fit on a 9 inch rim quite OK. Not all cars are exactly the same dimensionally [although they are close]. The front arches probably need rolling [preferably with a proper rolling tool although I would really like to watch Mark in action with his baseball bat- just not on my car though!] and the rack will need an additional spacer each end but other than that they fit fine. I needed the spacers to avoid contact with my Devek roll bar [the first point of contact]. I believe more recent offerings have better inner rim clearance- a limitation of the Devek bar which otherwise is an excellent piece of kit.

You can fit wider front sections with [more problems?] but just remember that you will have a hard time getting the rear end to keep up with the front unless you have meg rubber on the rear. Having said that you chaps in Finland like driving around with your rear end hanging out I believe- presumably you are not contemplating the "1000 Lakes". I know you have some very long summer days in Finland but how many of them do you have in a year where you can drive and get the rubber warm enough to grip correctly?

With a front camber of 2 degrees I see no noticeable heel wear on the front tires but then I do not do high mileages and extreme heat/age finish my tires long before they are anywhere near worn out.

Indeed, my stock GTS front wheels fitted with a 235 front section give excellent traction and I only really notice the difference on the few occasions I actually manage to get on a track day

Regards

Fred R

hacker-pschorr

Thought some of you might find this interesting.
The ZR-1 Corvette (the 2nd generation from 1990-1995) had 275's up front, 315's in the rear.
Its little brother, the LT-1, wore 255's.


The currnet ZR1 has 285's in the front, 335's in the rear.