help me pick rim size, offset, tires for 930

aftermath · aftermath's Garage

I have a 84 euro 930 with skinny ugly bbs wheels.
Help me pick a wide set of new wheels. Im not really looking for brand, Im looking for size, offset, width. Keep in mind I want to go as wide as I can without running into problems or needing modifications. As far as I know it has stock spacers on it now.

Or would people suggest setting ride height first, etc, then measuring for a 'perfect' fit.

If you have rim sizing, please provide tire info that would work with that rim.

This 930 car will be for the street with the odd autocross, my 911 already has 225/265! And it bugs me that the 930 has 245 on the back currently.

diabolos88 · 04-13-2006, 01:26 PM

1st what rim size you want to go with, 17 or 18?

as your probably already have on your car now, the 16s ddont offer any tire selection at all.
the 17s are almost the same, thin selection. There are some 315/35s on 17s but not too many.
the best selection right now is 18"s.
but the cost per tire is pretty high.

the widest tires you can put on a 930 are 275/40 front and 315/35 rear. The fronts will rub lock-to-lock, so you need to be careful or you can damage your A/C lines. Your also going to need to roll the lips, which is a good idea anyways when you think about it.

I think I would get your wheels first then lower the car once they're on.

what "ugly" wheels are on it now?

RarlyL8 · RarlyL8's Garage

You can get 335/30-18s out back easy on 12x18 wheels.

diabolos88 · 04-13-2006, 01:32 PM

really? no rubbing? hmmm

diabolos88 · 04-13-2006, 01:33 PM

RARLY8,
what about upfront width on 18s?

RarlyL8 · RarlyL8's Garage

255s easy, 275s with proper camber or fender roll.

For many years I ran 255/45-15s and 345/35-15s on my car. Required some real easy mods to make it work.

Right now I've got 255/35-18s on 9x18 front and 315/30-18s on 10.5x18 rear. The rears could grow a solid two inches and not touch a thing.

diabolos88 · 04-13-2006, 01:57 PM

got any pics? Im in process of picking new rims myself, was about to go the 17" route for fear of rubbing with the 18s.
But I much prefer 18s since there's are alot more tire selection.

slow&rusty · 04-13-2006, 04:27 PM

I just went down this road...

I bought 17x10.5 for the rear running a 275/40

Front I bought 17x8 running a 235/45

I went conservative to be honest and did not go the widest and fatest due to weight and knowing that I wanted to lower the car as well.

Hope that helps.

Yasin

RarlyL8 · RarlyL8's Garage

255/45-15 on 9x15 and 345/35-15s Yokos on 12x15 Fuchs

255/35-18 on 9x18 and 315/30-18 Pirellis on 10.5x18 Rooks

RarlyL8 · RarlyL8's Garage

315/30-18s are actually not as tall as 315/35-17s and less than 1" taller than 345/35-15s !!

RarlyL8 · RarlyL8's Garage

Here is a good picture to show the difference between a 345/35-15 Yoko and a 315/30-18 Pirelli P-Zero Rosso.

One often overlooked fact -- different tire manufacturers have different rulers. A 345/35-15 Pirelli P-Zero is a full 3/4" MORE NARROW than a 345/35-15 Yokohama AVS Intermediate. I found that out the hard way!!

diabolos88 · 04-13-2006, 08:17 PM

Rarly8,

where did you find those fat 345/45x15's?

aftermath · aftermath's Garage

ok, great, lets say 18 inch, Ive been finding out how hard is it to get rubber....rarlyl8 I seem to always see your posts and responses

aftermath · aftermath's Garage

I still have no offset info.....275 for the rear seems a bit too conservative, 345 well that seems a bit much if you dont get the right tire and offset bang on. Not that I wouldnt mind a 345 on the rear.

RarlyL8 · RarlyL8's Garage

Offset. My 18's are 9" front with 7" of backspacing and 1.5" spacers.
Rears are 10.5" with 7.5" backspacing and 2" spacers. Bill V should have all kinds of sizing info for a 930 on his spreadsheet.

You can easily alter the spacing on your car if you use long studs.
For example, my 12x15s used 1.5" spacers. When I swapped them out for the 18s I changed the spacer to 2" using the same studs. Makes it real easy. I beleive the stock setup for the 930 uses 2" spacers in the rear.

Ideal Tire/Rim Size. 255mm front on 9" and 315mm on 11" rear will fit nomatter what the rim dimeter or who the manufacturer is.

If I could have any size I want it would be 265/30-18s on 9.5" front and 345/25-18s on 12" rears. Too bad they don't make that size.

345s. I bought them from tire rack during their close out years ago. The ones pictured ended their life at a DE event last year. I still have one hermitically sealed set left.

Yes I post too much. Porsche is a drug.

Puka Puncha · 04-17-2006, 05:49 PM

RarlyL8....that is one sick ride

. Got meat?

aftermath · aftermath's Garage

Ive seen some charts from Bill, but when I saw his charts I dont recall any 930 info, just 911.
Ive just done a search for his posts, Can someone point me to the chart? I scanned through several posts after searching but I didnt find it.

gumba · 04-18-2006, 06:23 AM

Diabolos88, Michelin makes fat 15" tires. They're pretty pricey. 335/35/15 for $443 ea. through Coker Tires.
http://www.coker.com/store/customer/product.php?productid=18328&cat=274&page=1

diabolos88 · 04-18-2006, 11:31 AM

any fat 16"s?

derickc · 04-18-2006, 01:08 PM

Keep in mind that you want to keep the overall diameter relatively close or you will throw off the front/rear height and weight bias. You can get the overall height on tirerack.com under "specs"

I've got 235/45/17s up front and they barely fit (the 18s aren't as tall). I 've got 285/40/17s on the rear with no problems.

-dc