rawky

I've been looking for a new set of wheels for my S4 for a few weeks now, and I'm turning away from any wheels with a front offset lower than e55, but would an offset like et52 sacrifice handling?

Dean_Fuller

all depends on the width of the wheels...I have 8.5 in the front with et55 and 10" in the rear with et47 and they are fine...50 in the front would of been better though.

rawky

Does that mean you can go below et55, as long as the tyre is wider? So would 7J be too thin?

AO

I wouldn't go with anything narrower than a 7.5" wheel. IMO an 8" wheel would be better.

As for offsets (a.k.a. ET), this is how much material has been removed from the center of the wheel toward the outboard side in mm. So a higher offset will bring the wheel inboard. A low offset will push the wheel outward. Too low of an offset can cause the tire to interfere with the fender. OUCH!

55ET seems to be about ideal on a 7.5 wheel, but you can go as low as 50ET, but some people experince tramlining. On a 7" wheel you might be able to go as low as 45ET, but it would be far from ideal.

Dean_Fuller

Just checked mine again...fronts are 8" wide with ET50 and rears are 10" wide with ET47....NOTE I did not use any factory spacers on the rears. No scrubbing inside or out.

rawky

How is yours for tramlining, etc?

Dean_Fuller

I don't TRACK my car and am happy with the set up. I feel no ill effects from the front. The difference in 50mm and 55mm is about 3/16"....fairly small IMHO. I have seen the same rear 10" wide wheel with ET65 but I believe that would require a spacer to clear inside. Thats why I went with a ET47 in the rear...no spacer and to me fits as well as any 10" wide wheel can on the rear. If your looking at a wider or narrower wheel then ET adjustments will need to be made.

dr bob

The effects of the different offsets can be subtle or they can be brutal. So much depends on tires and width, but more importantly on the driving conditions. The cars are designed to cruise at warp speed, and the suspension is designed for a specific offset that keeps more tire on the inside of the pivot point than outside. Think of that 'pivot point' as the center of the tire's turn, a line drwn through the centers of the ball joints. 65-67mm of negative offset in the front is the original design point. 55 still has the tire pretty closely centered over the pivot point, but now slightly outside. 50 is now outside that point. How is all this important? Consider that you are driving along, and one front tire is suddenly slowed by something. Might be a rock, a dip in the pavement, a chuckhole, a change in pavement surface, or at the extreme, a blowout. There's a tendency for that side of the car to slow down, so the car swerves to that side. Driver corrects with steering, all is well. Porsche moved the center of the wheel inward so that the pressure on that tire will do the steering correction for you, so you don't even notice the change. The effect is consistent as speed increases, and is transparent to the driver. Now move the wheel out some, and that self-correcting steering is gone. "Tramlining" is the steering reacting to several things, one of which is a change in road surface. A change in rolling resistance will cause the car to steer towards the side with the highest resistance. This is opposite of what was designed into the car. The effect gets greater as speed increases.

So ya gotta ask yourself, are ya feeling lucky? What do you really want the car to do when you have a change in rolling resistance on one front wheel? As you move the wheel out, the problem becomes much more acute. Someone mentions that 5mm is only 3/16" inch, what will it matter? Think about it as almost 6 times the offset that a 55mm offset wheel gives you, and in the wrong direction.

My only somewhat educated opinion is that 55mm is the absolute minimum that one should seriously consider for a street car. YMMV, of course.

stealth

I've had 17x7.5 et 47, 17x7 et 55, 16x7 et 65 and et 60, and 18x8 et 52 on various 928s. I agree that less than 55 front offset is undesirable and causes the tramlining effect, to differing degrees depending on tire tread and size...but I decided that I had to forgive the et 50 on these factory polished 40th anniversary 911 wheels. If/when I do track time again, I may decide (both for cosmetic and handling reasons) to get a better-fitting set. I think a lot of people are happy with the 18" aftermarket sets with the et 57 fronts that can be had for a decent price. The et 47 set was a bit sloppy on my old 86.

Cosmo Kramer

Mathematically, 52 et on an 8" wheel rides in the identical position on the inside as a 65 et on a 7" wheel. That means the extra 1" of width goes to the outside. To equally split the amount inside/outside on a wider wheel you have to go with identical offset as stock. As the post above states, the et 57 fronts from late model 911's seem to work well offset wise. I am putting et 50 8" wide turbo twists on the front of my 85 so hopefully the handling will be OK.

martin D

I had 18"x10" et65 Sport classic II's (with 265's) on the rear of my '87 with no problems, could have done with a 15 to 20mm spacer for them to fill out the arch a bit more though.

Cosmo Kramer

Bob: Can this be adjusted a bit of negative camber? Just a thought?

dr bob

No. The ball joint relationship with the wheel is the same no matter where you move the ball joint relative to the car. Sorry!

Dean_Fuller

Martin,
I will agree...however I would guess the inside lip is very close to the rear shock base.....but probably not as close as some front calipers I've seen to inside of wheels. My point was the ET47 on a 10" wheel just fills the wheels well nicely and is off 3/16" from stock.

Allthough... I agree the front ET50 on a 8" wheel is NOT ideal. Outside edge of my wheel is 1 1/16" farther away from face of hub than the stock 7" wheel.....but with the wider wheel the inside edge is only off 1/8" different than stock.

dr bob

Dean, there are obviously two priorities for you. One is actually finding a wheel-tire combo that will bolt on to the car with minimum interference with body and suspension. The second is how the car will drive.

FWIW, that ET47 front is off 20MM, more than 3/4" from stock, not 3/16" as you state. It is off about 3/8" from the zero-scrub point, in the wrong direction.