Dean_Fuller

I thought the OP asked about Wheels and not tires. I agree with Larry the 205's in the front are too small but 225's fit great on both wheel and car. My son's wheels ( off a 1999 Boxster ) are front 7" 55 offset rear is 8.5" 50 offset. We mounted 225/40 17 in front and 255/45 17 in rear. Does a good job of filling the wells. You could always go bigger but for $300.00 it was a good deal and looks alot more updated than the phone dials. I know your car is newer but I think the geometry in similar.

Kolbjorn S

As per rule of thumb, ideal ratio tyre to wheel width for a 928 should be in the range 0.85 to 1.15. Thus, with a 7" front Boxster rim (7x17 ET55) maximum safe tire width is 205, giving a ratio of 1.15. With a 225 on the same rim, the ratio becomes 1.27, which is above what is regarded as recommended and what I interpret as the "safe" limit. If I understand correctly, it is related to the pressure (flex) excerted on the tire sidewall: ie. with a ratio greater than 1.15, the flex is greater and the (remote?) chances of a catastrophic failure under heavy load increases.

Having said this, putting 245 on 8" rims gives a ratio of 1.20.... (maximum width recommended for 8" is 235). But as we know, Porsche themselves put 245 on 8" rims.... so I presume this is where the limit goes.

bernard farquart

I am resurrecting this thread, because I have stumbled across a deal on a set of boxster wheels for a good price. (500 bucks, no rash, no dings)

They are 6" fronts, 7" rears. The markings on the wheels say 6 50 on the fronts, 7 40 on the rears.

My tire guy says "no problem" fitting 225 50 16 tires on them, which is stock tire size, on both rim sizes, why would this be a bad idea?

or, conversely, has anyone used these rims on a 928 with good results?

they look like the one pictured here.

edit: this is on an 84

pcar928fan

That is a pretty narrow front wheel for a 928. I think the only wheel that narrow (and I am not 100% sure about this) was the 15" diameter phone dial used on the '78/'79 automatic cars... All other 928 wheels were at least 7" wide on the front... Not sure about fitment...someone else will have to help you there.

Good luck.

dr bob

Keep shopping. Be sure to get --at least-- 7" fronts.

I added a set of 7.5" fronts/ 9" wide 17's to my S4. Brand new takeoffs, they came with 205 fronts. Turn-in was great, but total grip left a lot to be desired. I drove them 15k, and replaced with 225. Big difference. Enough that I may try 235's next time. To your situation, you won't have the option to safely go to 225's on the 6" front rims. You'll might miss out on a lot of the safety and handling that you have on your 7" originals. Tire technology has changed drastically since the car was built, making it possible to get original performance with a 205 current-technology performance tire, but no room to get better on the skinny rims.

My two cents.

Ninespub

Check out the "wheels & caps" site on ebay (no affiliation). You can get "new in the box" 18" or 19" 5-spoke carrera wheels for $499 plus $80 frieght and get an even newer look on your 928 than the old TT and not compromise the proper fittament or your safety. Just thought I'd let you know!

Paul Barrera '91 $$$$4

JPTL

Coming from somebody who ran 17" Boxster "S" wheels w/the stock 205's up front for a while, +1 on what Bob says.
IMO, the Boxster "S" wheel looks & fits much better than the standard early Boxster wheels.
But with the stock 205's that Boxsters came with, the looks vs. handling tradeoff that 205's up front pose simply isn't worth it.
After going to 225's, handling improved dramatically.
Bernard, I recall that going to 225's on a 7" wheel was a stretch. I'd get a second opinion on a proper fit of a 225 on a 6" wheel, if I were you.
Stick with your stock wheels/tires until you can get at least 225 up front, with the proper offset.

6mil928

I'm running a 225/50/16 on a 7" rim. In fact that's the stock size. I was told I could run up to 245/50/16 if I wanted to on my 7" PD's.

devilinblack

Those wheels are exactly what I bought a couple weeks ago and have on there now. The stock tire size for the 6" front wheels is 205 55. I put 225's on the front and they look rather clownish with the sidewall sticking so far out past the rim. My plan is to take the current tires off and put 205 55 snow tires on and keep them for my ski trips. BTW, mine were missing the center caps and have a few small blemishes and I paid $160 for them with 2 good tires. You should be able to get much better wheels for $500, IMHO.

Let me know if you want some close up photos of how the 225's fit on 6" wheels.

SeanR

Don't try 225's on a 6". There has been some discussion about 225's slipping off the 7"'s here in DFW. I don't believe it because I've run them for 3 years, track/street with no problem. I don't think they would work well on a 6" front. 205 is the most I'd go on a 6".

Then again, if you are not putting the car through any heavy stress turns, it might work. Or it might not.

bernard farquart

Thanks to all who responded, I think I will pass on this set, I wanted to update the look of the car, but not at the expense of traction.

Now I am considering getting a pair of 8" flats for the rear, and picking my best two 7" wheels for the front. This way I will actually improve, instead of degrade my cars performance.

Thanks again to all who chimed in!

Joe '87 S4

Anyone buy these? The feedback from the seller is close to perfect but the deal seems almost too good. Will these fit my '87?

http://cgi.ebay.com/ebaymotors/18-8-...to#ht_4064wt_0

no doubt

I don't know it to be fact, but I was under the impression that wheels are interchangeable (fitment wise) on all Porsche models from 1987 to 2008.

6mil928

Yes they'll all fit 5x130 the question is if you can drive the car afterwards. If the ET is wrong your screwed. The offset is what makes or breaks rim fitment.

Joe '87 S4

They're 18" x 8" 55 Offset Front, 18" x 10" 65 Offset Rear. The tires they have on them are 245/40 front, 265/35 rear. Where's Andrew's wheel calculator...I knew I should have downloaded it for future reference.