7 and 8 x 16 tire options

farleyd · farleyd's Garage

Hi to all, i made a search but didnt find quite what i wanted. So...

My front 7 x 16s has Bridgestone 225/50/16, which is weird i guess. Two questions:
1) What would be the matching tire size for the rear 8 x 16s????
2) Should i rather fit the 225/50/16 on the 8s on the back? Then what would be the appropriate size for the front 7s?

I have an 1979 SC.

Thanks!

Mike Feinstein · Mike Feinstein's Garage

You could go with 245-45-16's in back on your 8's. If you move your 225's to the back, you'll need 205-55-16's on your 7's up front.

farleyd · farleyd's Garage

Thanks Mike, exactly what i wanted to know.

Arent 225 on 7s and 245 on 8s a little too much???

marcesq · marcesq's Garage

Quote:

Originally posted by farleyd
Thanks Mike, exactly what i wanted to know.

Arent 225 on 7s and 245 on 8s a little too much???

Nope . . . . but the limit has been reached on the 7s

pjv911 · pjv911's Garage

I have carrera flares on a 69` and stock front fenders . I managed to fit 9x17 with 255/45/17 in the rear easily and 8x17 with 235/45/17 in the front also with no problems. I find that if you have 23.5mm neg offset wheels you can go bigger without issues. My fender lips are all rolled but it wasnt even nessesary.
BTW the car is almost finished. These are pics from 2 months ago.

Kurt Williams

farleyd · farleyd's Garage

Will 225/50/16 on 7s up front cause rubbing? I have an SC. Thanks!

Todd Simpson · 12-11-2003, 01:14 PM

Quote:

Will 225/50/16 on 7s up front cause rubbing? I have an SC. Thanks!

Yes. With negative camber and rolled fender lips they will fit on *most* cars.

PS-Kurt-The car looks great...you need some cool seats though, don't you? :-)

pjv911 · pjv911's Garage

Cash has been a problem this past month. Spending on the car will pick up again in a few weeks.

Kurt Williams

Eric Coffey · 12-11-2003, 03:11 PM

IMO 225's on 7x16's and 245's on 8x16's are too big. All things being equal (tire compound, aspect ratio, etc.), you would be better off in the fitment and tire geometry/handling departments if you stuck with 205's on the 7's and 225's on the 8's.

pjv911 · pjv911's Garage

Way off eric. 205`S on 7" rims are way too thin. Porsche themselves put 225`s on the 7" rim(the early 930 cars and late 80`s carrera`s) . 245`S could even be considered ok on the 7`s if the clearance is available. 205`s belong on 6" wheels and no bigger. You had a 1988 carrera didnt you ? That should have come with 16x7 in the rear with 225/50/16 from the factory.

Kurt Williams

farleyd · farleyd's Garage

Eric, what was your set-up Fuch/tires speaking on your sold Targa? Thanks!

farleyd · farleyd's Garage

pjv911, back from Anderson´s book, recommandation from Bruce and stock Porsche configs are:
7 x 16s > 205/55/16 when fronts
7 x 16s > 225/50/16 when rears
8 x 16s > 225/50/16
9 x 16s > 245/45/16

Look what my 7s with 225/50/16 look like, they are on the bulgy side in my opinion. Too round i guess. Your thoughts guys?

goat · goat's Garage

On the back of mine I have 7's with 225/50/16
They are on the bulgy side. The tire sidewall really sticks out.
My replacements are a set of 8's, just purchased, which I have decided to run with with the same tire option.

Eric Coffey · 12-11-2003, 04:09 PM

Quote:

Originally posted by pjv911
Way off eric. 205`S on 7" rims are way too thin. Porsche themselves put 225`s on the 7" rim(the early 930 cars and late 80`s carrera`s) . 245`S could even be considered ok on the 7`s if the clearance is available. 205`s belong on 6" wheels and no bigger. You had a 1988 carrera didnt you ? That should have come with 16x7 in the rear with 225/50/16 from the factory.

Kurt Williams

Sorry Kurt, but you might want to do a little homework beofre telling someone thet are "way off". The factory used 205's on 7" (front) rims on the 930's, with 245's on 9's. 205's on 7's are NOT "way too thin". What do you base that on? The statement: "245's could even be considered ok on the 7's if clearance is available" is even further off base. Just because they will physically fit, does NOT mean they are correct, or optimal. 245's on 7's will give you way too much "ballooning", and exaggerate sidewall flex, seriously degrading handling.

Yes, the factory also used 225's on 7's, but ONLY on the rear. I still think that is the wrong choice for that rim, but who am I to argue with the factory. My main point though was that (sorry should have clarified) I think 225's on 7's are too big if used up front, when you go with 8's/9's in the rear. The only way I would use a 225 up front would be on a 951 8x16, with 9x16's in the rear on 245's.

farleyd-

The Targa originally had 7x16's in front with 205's and 8x16's in the rear with 225's. The handling/grip was superb. I ended up selling them to fellow board member Gary Carlton, who then sold the car to Leland Pate (he changed tires I believe, but kept the same 205/225 sizes).

farleyd · farleyd's Garage

Ouch, i just discovered a not so funny thing. I just bought some Automotion 8 x 16 Fuchs repro, only to discover that they are polished and that my 7 x 16s are.... anodized! IS there a way to convert one to another????? Aaaaarghh!

pjv911 · pjv911's Garage

I agree with the 7" in the front part only because of clearance. And yes now that I think about it you are correct about the 930 tire sizes. My mind has been kinda weak these past few days due to lack of sleep. Heres a picture of my other car which has original the 69`-73` flares with 225/50/16 yoko`s . I think the bulging is just right on the 7`s. I have 205/55/16`s on the front with 6" rims . Rear quarters needed to be rolled as well as the oil cooler lines needing to be relocated. Some tire brands are different dimentions even though they run the same size listings.

Kurt Williams

Victor · 12-11-2003, 04:25 PM

You really should open a tire/wheel shop! I use 225 on 8" because the $ jump to 245 is not worth it.

goat · goat's Garage

Kurt..
Really nice Fuch's.
The tire & wheel combo on your rear does not look bulged at all. mine with 7's & 225/50s bulge alot more I guess it comes down to tire brand and maker.
I do love those wheels though.

pjv911 · pjv911's Garage

Hey you guy`s should write a letter to nissan ,toyota , porsche , etc and tell them that they should not be putting 225`s on the 7" rims because you feel its not right. Anyone got a picture of a 205 on a 16x7 rim ? I would look terrible and unsafe. Nevermind the curb damage you would get to the rim lip if to rubbed . I give up. And Eric it was just a poor choice of words in saying way off. Thats how I feel but I didnt intend to sound so bold in saying so. Either way its not my car or my decision. Ive been a import performance tech for over 15 years(including many many porsches) and in all my time I have never seen anyone use a 205 on a 16x7 rim while on the rear . It just dont fit correctly nor does it look appealing at all. Using a 205 in the front on a 7 is just the easy choice because of clearance. But if it were me I would use a 16x6 up front .

Todd Simpson · 12-11-2003, 04:54 PM

Quote:

who am I to argue with the factory

The factory ain't the last word on a lot of things. 9's and 245's look and work great on an SC, but were never offered as an option. Yet most of us have them or want them.

If you're tracking or autocrossing at all, try to get the 225's up front. If it's just a street car, I'd go with 6's and 205's for less steering effort. IMO, 7's and 205's are the least ideal as you get additional steering effort due to offset, without the additional grip of a 225.