I just got my 17 x 7" 993 wheels. I was told they are a 55 mm back spacing, and I would need 20mm to make them fit
When I measure from the back side its 5 7/8 to rim edge.
I measure my 15" deep six wheel its 4 7/8 to rim edge.
20mm is about 1/2" right? It would appear I need 1" spacer.
Am I missing something? Once again, what size spacer have others used for this aplication?

thanks for your help.

1" = 2.54 cm = 0.7874" = (about) 3/4" ...

never touched those rims, so i can't say anything about how they will fit or not.

does your car have flares? rolled fenders? what size tires right now? how wide are the current rims?

a 3/4" spacer or 1" spacer requires longer studs!

the smallest bolt on adapter spacer you can fit is 1" + 1/4" flat spacer with holes for the nuts. (that's what i use in the front)
or a 1 1/2" bolt on adapter spacer, for which you don't need an additional flat spacer. (that's what i use in the rear)

Andy

thanks for your reply Andy.
No flares, rolled fender lips. Right now it has 15 x 6, with 1:95. Thats the way I bought it a month ago. So I am in the initial stages of upgrading appearance. Mechanically its set up fine for me. After wheels & tires bigger brakes.
I don't want a bolt on adaptor, I want to get longer studs.

ok, cool. then it's easy

just measure the difference in backspacing and get solid spacers and longer studs ...

unless, you want to move the tire a bit more inward (and you have the space to do so),
in that case, get a thinner spacer ...

Andy

I have 1.5" spacers all the way around. 7x17 front 993 wheels and 17x9 in the back

Paul, minor detail, you have flares in the rear, he does not

try this again

These are the bolt on kind no need of changing the studs

oh yea:



don't rely on hearsay, get the facts

the offset is cast/stamped on the rim

Paul, depending on the organization, the bolt-on spacers are sometimes frowned upon...never seen one fail, it's one of those things that'll always have people on 2 drasticly different sides of the topic.....

well i think he will still have to use the 1.5" spacers even if he has 7" rims for the back the lug nuts are deeper into my rear rim and I think that the distance from the back of the wheel to where the face that touches the rotor is the smae for both size rims. I could be wrong but I went outside and did a rough measurement.

The best way to see how much spacing you need is take your time and do a rough mount of the wheels. use some wood or something as a adjustable spacer. Also remember that all 914's are not created equal.

I'm not going to debate the spacers here but we can start a new thread.

retrotech, If you like I can put one of my front rims on the back of my car to see how it works with the 7" rim on the back. It'll have to be after work tomorrow though.

I spent a whole day figuring out what size spacers I needed for my rims. It took the time and did it only once.

All I have ever heard from the 911 camp is, no way bolt on spacers for track use. Personally I don't see anyway they would fail. You actually would have 2 sets of shorter studs. Is there any thing I am missing about bolt on spacers. I happen to have a pair of bolt on 1.5".
I see why with flares you would need the 1.5", but with stock fenders that seems too much.
My next problem is I want Falkens, but they only make 2.25x17. Looking under the car now in rear, with 1.95 I see less than an inch of space. It seems a 2.05 will be close.
I can't go buy one tire to see if it will fit.

retrotech,

Here is a little info that might help concerning backspacing. I have a set of Revolution RFX wheels, 15 x 6.5, with 5-1/8" backspacing with 205/60 tires. they clear the inner rear without problem, with no spacer. Your 5-7/8" backspacing is 6/8" or 3/4" greater than this.

I don't mean to burn you out on the list, but I am really confused here. I just mounted a 17x2.25/50 tire on the rear with 1/2" spacer. It seems to fit, but with only a small amount of day light clearance. It is a 55 mm back space, so 1/2" shouldn't be enough. Since I borrowed one tire, and don't have long enough studs I can't drive it, but its in there.
Now I don't know if I even like the look.
Give me some input. I seem to be convinced I want the Falken Azenis tires no matter what. And I thought I liked the 17" 993 wheels.
Opinions?

not sure if I like them on there or not...I like the "Hot Wheels" look of the Fuchs on your car......nice garage !!!!!

I too wanted the Falkens, but I think the 225's are too wide for the 7" wheels
(I know they'll fit, I'm running 225/45/17's on 7's on my Volvo)

spare set of wheels/tires for auto-x or when you really want to tear up the roads with the Falkens installed????

Be carful that you are measuring the clearence on the back of the wheel. Meaning the space between the tire and the "trunk wall" The outer fender can be rolled a little if need be.

The 993 wheels look funny b/c you only have one on the car. the fuchs are not a compliment to the 993's.

Just out of curiosity why do you say 2.25/50 not 225/50? I have 225's on my 7 inch rims but the tires have rim guards that add that width.

Look at my site (link below my name) for some picks if you need to decide on the look.

The idea behind test fitting the wheels is, as I understand it, to figure out what size spacers you need. Mount the wheel/tire on the car. make some wooden wedges that will pretend to be your spacer and they will be adjustable. when you mount the wheel check the clearence on the backside of the wheel/tire and the trailing arm. (I think I had to move my brake line a little so the wheel/tire spun freely. After you have the back spaced correctly then see what needs to be done at the outside of the wheel/tire and the quarter pannel. I think you are puting to much thought into the spacers. Figure out what you need and then find out what sizes you can get. keep us posted on the progress.

Thanks for the picture of your car. I think if I had flares I would like better. The 2.25, was a slip on the key board.
Maybe you are right about the fuchs/993 combo, but I could only borrow one tire for fit test.
The 1/2 spacer seems right. Fenders already rolled. Its such a tight fit, I think I might have problems in hard cornering.
I definately want to use Azenis, and in 17" the smallest is 225.
I may regroup with 16" Fuchs and do something different with the finish. Perhaps sand blast for a American Mag look.