4thChild

My 2 cents. Just got em, love em. I think the cars rides better now. Could it just be in my head?

Fishey

There are so many factors that can change what is better between a 15-16-17-18 that its all speculation.

Ray S

I had a great time, but I'm not ready to play with you full on Club Racers................yet! (maybe someday) 19 places is awesome, too bad about your brakes.

You doing any more events this year? I think I'm done till '06.

See you around!

John D.

Jezuz H Christmas... I believe folks - who are new - deserve a bit of latitude. Yea, they search the Forums. Yea - they try to ask the "right question". And yea - it's forkin' intimidating enough to post a question in front of 250,000 readers per day.

Cut some folks some slack, OK? If not - I'll have to tell you about the wheel offsets I ran on my 951 (I've owned 2 - so there is a lot of room for screw-ups )

Back on subject......

John D.

Dave in Chicago

Ray - I may do the Oktoberfest weekend if I can scrounge together enough braking. I have rubber left on the RA-1's that's just itching to be ground down at Blackhawk. We'll see, I have a week or two to decide.

Otherwise, it's winter wrenching time for me...

Fishey

John to tell you the truth I never use search any more because if I make a mistake and search the wrong words then I have to wait a MINUTE AND A HALF before I can search again.. Its faster just to make a thread and be bashed for not searching.

kevincnc

Those wheels look great! That's what I want for my '89 turbo.

It seems to me that the lower profile tire would improve handling because of reduced side-flex. Maybe someone can explain why if that's not a valid assumption.

Where did you get them?

Thanks,

Kevin

m21sniper

"Not with most modern ultra-low profile tires. So many OEMs use them today that it's not the same. One big mistake many people do is run them at too high a pressure and then say it's the low profile tire when it's not."

That's not been the case with all the ghetto hoopties i've repoe'd(and we're talking well into the many hundreds), which typically have the ride quality of a horse drawn carriage. But eh, there is no such thing as an absolute rule.

"It will do ZERO to your suspension geometry unless you actaully do something to change your suspension geometry and then that is not caused by the wheel/tire combo."

That part's not true. If you change ride height, by definition, you change your suspension geometry. If the new tire/wheel combo is significantly taller overall(which is often the case in these wheel 'upgrades'), then you'll have to run the suspension higher for wheel well clearance, and as i said, that does affect geometry.

Choose wisely, there will be no need for adjustment. Choose poorly, and you can really monkey up the geometry.

tifosiman

Hey John,

I didn't do anything to deserve that "****-off" commentary from Mr. Raven. If you are hacked at me for replying to him in kind, then I apologize.

Geo

There is likely something else going on there. Could also be they are over inflated as many ultra-low profile tires are.

This is incorrect. I could dramatically increase or decrease my overall wheel/tire diameter, but if I do nothing else to the ride height, the geometry does not change one bit. Also, adding larger wheels properly does not increase the overall diameter. It's a pretty simple matter to choose the correct tire size to keep the overall diameter the same.

Only if you further adjust the ride height with different springs or adjust your coilovers (if you have them) and then that is not an issue of the wheel/tire combo unless you run 20" wheels or something like that and have to change springs or whatever to adjust the ride height even higher.

Keep in mind, if someone does this, why makes it any different from the person who lowers his/her car?

Travis - sflraver

I run 15x8 Fuchs on all 4 corners, NA spindles, light brakes and a few other front suspension widgets.

Bigger wheels are not just about lag going forward. They add a considerable amount of unsprung weight to the front (and back) end. The more unsprung weight you have the slower the suspension reacts because it has to get all that added weight moving. This in itself helps to cause a poor ride and would require larger sways, koni's & springs just to get back closer to a "normal" suspension reaction time.

But.. the thread title is looks vs. performance. Getting back on topic-ish... I would pick out a few wheels that I liked and then get weights on them. Go with the lightest of the bunch and that can be your compromise. Looks and performance. Its a Porsche after all... you should be able to have both, Right???

Geo

The tires themselves are still going to play a much larger role in the ride. I know this from direct experience.

Oddjob

For what its worth, here are some numbers to take a look at:

I dont have info on any factory 15" wheels, but I would guess they are in the 15 lb range.

Factory Stock 16" wheels (phone dials, Club Sports, Design 90s) are all around 18 - 22 lbs depending on width (7" - 9").

Factory Stock 17" wheels (964 Cup I, 993 Cup II) are between 20 - 26 lbs (7" - 9").

Factory 993 18" Twist wheels are between 20 - 30 lbs based on width (8" - 10") and whether they are the Turbo hollow spoke or the solid cast wheels.

Ive personally weighed 10 x 18" BBS 3 pc Race wheels and BBS RE wheels, and they are both 20 lbs and a few ounces.

Tires (I looked as Hoosier S04s since I have that info handy):

225/50/15 weighs 20 lbs
245/45/16 weighs 21 lbs
245/40/17 weighs 21 lbs
245/35/18 weighs 21 lbs
285/30/18 weighs 22 lbs

Hoosiers are about the lightest tires available. Different brands will not weigh the same as others, so make sure to compare apples to apples.

But with what I looked up, if you use a race/high quality 18" wheel with a 285/30 tire, it will only weigh about 1-2 lbs more than a 8 x 16" phone dial with a 245/45 tire.

Now how much difference will a couple pounds per wheel make - none. How much better grip will you get with a 285 on the back, quite a bit.

If you go with a heavy cast factory or cheap/replica 18" wheel, it will weigh up to 10 lbs, or more, per wheel than a factory cast/forged 16". Possibly 15 lbs more than a 15" wheel/tire. That will likely be noticeable, but depending on your use or the track, the trade off in grip versus acceleration may make one setup preferable to the other.

I have run 245/16s on 16" mag Turbo Cup phone dials (16 lbs per wheel) back to back with some 18" 3 pc Speedline 993 RS wheels (29 lbs per wheel) with 285/30 tires on my 944T at the track. The place I noticed the weight difference the most was moving the wheels around when off the car (sore back). When driving, there was probably a little less bite in acceleration with the heavier wheels, but the grip was noticeably better, so I could keep a little higher speed going through the corners. In the end, the car was faster (quicker laps), with less drama on the 18s than on the 16s.

Ive got some lightweight 18" wheels now, so my decision on what wheel/tire size to use is a no brainer.

Travis - sflraver

The couple of lbs of unsprung weight is not as noticeable in a track situation where you are not looking at uneven road surfaces (street) or hard quick turns(autox). I went on an unsprung weight diet on my autox car and in that application you can notice any reduction with a distinct jump in suspension response time.
I was able to shed over 12 lbs per wheel (front) and it did wanders for the cars handling. Before the "diet" I was running 15" phone dials with 60 series tires. Again, track events where the surface is even and you do not ask the car to respond as dramatically, unsprung weight plays a smaller role. In every day driving and autox you will notice it much more.

M758

Don't forget on teh 944 NA if you run 225/50 on 15" wheels rather than 16" you get the advantge of lowering gearing too. I rode in a 944 NA with light 18" wheels a time back. Grip seemed good, but accelration was poor since the diameter was actually larger than stock.

So for such a low hp machine you really want the lower gearing a 225/50 on 15" wheel can provide. The NA car has lots of grip, but no hp so what you need most is acceleration.

Once you move to 951 you have more hp and can get away with a larger tire. You have solid hp with these cars so you gaining a bit more grip is probably more important and a little bit more grip.

Also would seem that if you could get 245 or wider tire in 15" low profile that would be good for a 951. 225's really too small. Since you can't however you are forced in to 16" wheel. Then you lose the advanage of smaller diameter. So in a 951 16 vs 17 vs 18 is more an issues of wheel & tire weight and tire width as diameters tend to be similar.