C4ptainCox

It seems like every week there is a new thread posted that reads along the lines of "...how big of tires will fit without rubbing?" or "How much fender rolling is necessary to fit 18x11 Carrera III wheels in the back of my 928?" While I may be in the minority here, these are not the questions I lay awake at night pondering.

First things first, I have a US '81 manual with the chrome D90s off of a 944 with BFG G-Force Sport Comp 2's, 225/50r16 on the fronts and 245/45r16 on the rears. These are great summer tires that still retain good wet weather performance, but they're scary when it gets cold. On top of that, they're really too much tire for the car in the summertime. The problem is I can't just get another tire for these wheels because, as many of you already know, the only things available are summer performance tires in those sizes, and to put the final nail in the coffin the chrome on the D90's is separating and flaking off.
So not only do I want different tires, but different wheels...

If for some reason you're still bored enough to be reading, here is my idea:
I want to buy two sets of front wheels of the cup 1's, cup 2's, or 996 carrrera 2's. These wheels all measure in at 17x7 with et55. This would allow me to run 225/45r17 tire size all around which is the same tread width and almost the same diameter as what originally shipped with my car.

Pros:
* A quick search from Discount Tire reveals that there are 252 options in this size.
* Less unsprung and rotational mass.
* Better all season performance.
* Manufacturers mileage warranties from an non-staggered setup.
* Probably relatively inexpensive if I can find fronts on their own.
* A likely insignificant improvement in fuel economy.
* Less understeer.

Cons:
* Narrower tires won't look as cool from the back...
* Probably will need rear spacers to get the wheels to fit correctly in the rear wheel wells.
* Still not the optimum et65 spacing.

I still plan to avoid ice and snow like the plague but those are both relatively rare here anyways. So as far as what I'm looking for in the tire, I'm searching for an all season tire that breaks away predictably at the limits of its grip, something akin to the Michelin primacy HP that comes stock with Toyota 86's and BRZ's (although technically I think they classify that as a summer touring tire).

So tell me what you think. Is this a terrible idea? Is there a better way to accomplish my goals? Feel free to make tire and wheel recommendations too!


Am I crazy? ...Probably.

SwayBar

IMOO, I think 17's are way too small for the fender wells, and aesthetics suffer greatly as a result. The rims looks miniscule.

Snark Shark

I believe you can put 225's on 8 inch wide wheels. Just to give you another option since I think D90's are cool. Although they will look skinny from the rear.

C4ptainCox

If I could get four fronts of carrera III's then there are plenty of 225/40r18 tires available. I don't mind how the cayman s wheels look either. But both cases would result in adding back in most of the rotational mass that would be saved with the 17's.

I think it would bother me to have the front sidewalls round while the rears looked slightly stretched. I do like the D90's and they still look great from a distance, but that will change rapidly as the chrome continues to deteriorate...

hb253

You can get 18-inch Panamera 5-spokes and then have a wide variety of all season tires to choose from. The front et59 offset is pretty good too.

Hugo

SwayBar

Why are you concerned about 'rotational mass'? I'll bet you will never, ever notice a difference due to it, real, or imagined.

Just put on what you think is the best looking wheel, whatever that may be.

Hold On

I have three sets of wheels and tires I have run on my 83. 16,19 and 18. Each has pros and cons. The set that I am currently running are 18 in Panamera wheels. They are a far better ride than the 19`s and look better than the 16`s . I`m sticking to them.

GregBBRD

Owning a 36 year old car isn't exactly "normal"

Owning a 36 year old Porsche is pretty nuts.

Owning a 36 year old 928 Porsche definitely puts you past crazy.

Trying to find the perfect wheel and tire combination for 36 year old Porsche suspension geometry iwith 36 year old deteriorated rubber bushings is insanity.

Welcome to the group.....

hacker-pschorr

How old are these tires? BFG doesn't even show that tire available in that rear size, so either that's a typo or they don't offer them anymore.
I have the same tire on my S4 and recently out in low 40's in the rain they were fine. How low are the temps you plan on driving in? Much driving below 40 it may be time to consider two sets, one for summer and another for winter.
Unless you will be happy with an all season year round.

I'm not even sure what this means.

Where have you all looked? There are some decent tires on the market not sold through places like Tire Rack.

For example, Cooper makes the ZEON RS3-A, an all season tire in these sizes:
225/50R16
245/50R16

Yes a 50 series in the back will throw off the speedo a tiny bit. Small price to pay for a tire you might be happier with year round.

Shawn Stanford

No, you're not crazy: I went from a set of Carrera 18s back to the stock 16s (with spacers) because I prefer the look.

V2Rocket

inexpensive, long lasting, fun to drive, W-rated (168mph) good gripping A/S tires...and they come in 225/45/17

http://www.falkentire.com/tires/car-...x-ze950/s-tire

hacker-pschorr

That's gonna be quite the trick to fit those on 16" wheels.

V2Rocket

stretched tires yo

..
..

C4ptainCox

I recently had midterms during which I completely forgot that this thread existed. Sorry about the extremely late replies...


I really like this idea. I wasn't aware of this option. Plus I like the look of those five spokes on the 928 and they seem to be reasonably priced.


You're completely right. I'm too worried about weight in my GT car.


Yeah, I think I'm sold on 18's. Thanks for the input.


It's all true. Thanks for putting things into perspective.


You're right, I remembered incorrectly. I checked the car and the rear is 245/50r16. They're about a year old, not a lot of miles. I'll still put them on in the summer until they're worn out.

I'm really not trying to knock the BFG's, I think they're a great tire. They handle dry and warm-wet weather very, very well. With that said, in sub 40 degree temperatures they seem to break away much too quickly. I've had the small lips from leaving driveways break the rear end loose under very little throttle. Almost got me into trouble once.
In contrast to that, I've found the occasional power slide in warm wet weather to be pretty predictable and rewarding with these tires.

I'm sorry, that was a pretty vague statement. What I mean is that in dry warm weather, these grip so effectively that the limits seem to be well beyond what is achievable with my car. At least on the street. I find it entertaining to be able to flirt with the limits of a vehicle with spirited driving, hence "too much tire" in my opinion. I realize that many would probably disagree with me.

I'll admit I'm mostly looking for tires through Discount Tire. I've liked working with them and their rebates make them one of the cheapest options for me. Full disclosure, they did break the shifter on my VW Scirocco at one point, but they compensated me for it and now I pull my cars into their bays.
I think I'm pretty set on 18's now, but if I decide to go back to 16's those Coopers look like a very good option.


Those look nice. And it appears they are available in 225/40r18 which may be the size I end up with.



So the current plan is to pick up four of the front five spoke panamera wheels which will be 18x8 et59 probably with 225/40r18 tires, which is basically the same overall diameter as factory. I don't know the weight of these wheels, but I'm not going to worry about it.

Thanks everyone for your replies! I really appreciate it. Your knowledge is invaluable.
I'll update with details of what I end up with and eventually pictures too!

jeff spahn

I want to replace all those rubber bits. Anyone make a comprehensive list of what we need?