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18" wheels: What's the deal? Porsche says don't, but it seems lots of people do?
I love the look of 18" wheels on 944s, but I've read the Porsche warning about running anything larger than 17". Even still, there seems to be a lot of people who have 18" wheels, and not a lot (I cant find any) evidence (posts) about any sort of failures like Porsche warns about. So what's the story? Is it safe to run 18" wheels?
There's always a cause and effect anytime you change something the Porsche engineers originally designed. Detrimental...I doubt it. For my toy I like the look of the 18's. Really depends what your driving intentions are.
I'm running 18"'s. If it's for street it's. It an issue. On track there are some suspension parts that should be beefed up. Also for track you won't be running the most efficient gearing as it was truly designed for 15s with that horsepower. Again for street I've had no issues and consulted with indie shop specializing in 994s.
I love the look of 18" wheels on 944s, but I've read the Porsche warning about running anything larger than 17". Even still, there seems to be a lot of people who have 18" wheels, and not a lot (I cant find any) evidence (posts) about any sort of failures like Porsche warns about. So what's the story? Is it safe to run 18" wheels?
It's like this, car manufactures design a car to work well with specific components, and should anyone want to go outside these then there will be consequences and this could be fatal. EG if something broke and you had a accident you may be killed etc....this is why they declare in this case they DO NOT recommend fitting 18" hoops on this classis transaxle chassis that was designed in the 1970's.....
However car enthusiasts worldwide modify and change components up to and beyond these boundaries and a lot of the time it's to create "Looks" and or in my case "Performance".
Fitting 18's on your 944 will give it a unique look as illustrated above, it will however increase the 0-60 time , make the car slower and adversely affect the handling due to the extra weight, wide width, lower tyre profile and altered scrub radius etc..etc..the ride quality also will be very harsh compared to a 15" wheel & tyre.
It's a risk which only you can decide if you want to take, if the "Look" is the ultimate goal over performance and your happy to try it and accept the issues go for it !
Depending on what size wheels you have on the car now? a back to back test and subsequent test drives will certainly illustrate the 2 different diameters.
You may like the heavier less give harder feel, but I could guarantee if you ran the 18's for 2 weeks then fitted 15's the difference feels like the car is so much more agile and quicker because it is......
I would recommend upgrading the caster blocks to the more solid 968 style, but even that is probably more for improved handling rather than safety. I would not be concerned at all running 18" wheels on a street-driven 944 with the suspension in good condition.
Personally, I have 17" Cup IIs on my 944 and they're fine, but I keep an eye out for 16" Cup I wheels to replace them eventually. The car really does appreciate a smaller, lighter wheel, especially for street use where the taller sidewall is a bit more forgiving over uneven surfaces. 15" is a bit too small for my taste, though!
Porsche did put 18 wheels on 944 chasis and raced it so it should be fine.
"They should be Fine" coming from anyone is not the best piece of advice ever made!
No Production 944 Came with 18" Wheels ??
The only transaxle was the 968 Turbo S / RS, which was and is a very low production car (Less than 21!!!)
To quote "Race cars do it" or have them is as far out from a street / road car as anything, this mentally that if a Racing car has something for a street car, means it's fine is also POOR advice.
As I said you want to fit components on your car for "Looky Likely" you need to accept the consequences, some people will not go anywhere near this level of risk, others really don't give a "$%^ and just because MR X and MR Y have things fitted to their car and they think they are MINT, not to mention the old adage "Race cars have them" doesn't mean Jack squat or make it right!
Based on numerous 951's running 18s and based on factory 944S3 chasis with 3.0 turbo engine that had them factory fitted (pictured above), it is perfectly fine to run 18s. It's also safer as 18's are not as wobbly as smaller tires and improove stability, cornering. This is also why all sport cars of today are delivered with at least 18 size rims.
Is this better piece of advice?
As per documentation, they are indeed only factory homologated for 968 Turbo S.
I agree with 924srr27l, these cars do perform better on the street with the factory 15 & 16 wheels. If I were going to fit 18 for any reason I would at least use the later 87+ spindles and hubs with the larger wheel bearings and the 968 stronger castor blocks.
Voith, I cannot see how 18's are any safer or how they improve stability and cornering, that would depend on the car and not generally accross the board. If a cars suspension is designed around those 18in wheels, maybe so. Our cars seem to work better with some corner force transmitted to the tire sidewall and causing it to flex. You are not reducing that corner force by fitting 18's, you are simply redirecting it to the suspension bushes and causing them to flex more, as most street cars run soft bushes.
Based on numerous 951's running 18s and based on factory 944S3 chasis with 3.0 turbo engine that had them factory fitted (pictured above), it is perfectly fine to run 18s. It's also safer as 18's are not as wobbly as smaller tires and improove stability, cornering. This is also why all sport cars of today are delivered with at least 18 size rims.
Is this better piece of advice?
That is absolutely Brilliantly 100% the answer i thought you or other may say!
Modern car's have them etc... ! (Bigger Wheels)
Modern car's have been DESIGNED to use Bigger Diameter wheels,
To put this thread's question into a Modern perspective, are the members on the Cayman Forum who own a GT4 looking and considering fitting 23" Wheels?
(If they were available) ??
3" Bigger than designed is what we looking at here with the 944 chassis from 15 to an 18"
Even if a set of 23" Wheels looked "KOOL" on a GT4 Cayman but Porsche didn't recommend them, and and even if there were Cayman RACE cars fitted with them, it still doesn't answer and acknowledge the question :
18" Wheels whats the deal, Porsche don't recommend it etc..
The deal is in the Driving, NOT the way the car looks!
Based on what some people use on Numerous 951's is NOT for most or all people, so this adversity is not the norm or recommended hence why Porsche declare such information.
As far as 18's are SAFER ! for street driving than 15's because they are not Wobbly or use narrower Tyres is not correct at all! this is another debate and subject which many people just cannot or Will not ever get their head around..
The 968 Turbo RS is such a limited car it can hardly be called or quoted as a Factory fitted 944 with 18's. and what changes were made to accommodate the 18" Wheels, weren't they Magnesium anyway?
The absolute best performing factory made street legal version of 944 (968TS) has them. That is because they are performing better, not worse.
968 Turbo S is a street legal car with 18 wheels borrowed from the 964 (not magnesium) it was sold to general public for £70.000 and it's only rare because of it's price. (£70k in 90s was quite a chunk of cash)
Makg: stability of car greatly improves with less or harder sidewalls. That is why all the modern cars have big wheels. When you loose control of the car it is usually because of the uncontrolled sprung to non sprung movement. The less this movement is split between tire/wheel and sprung/non-sprung parts of the car the easier it is to regain control of it. Hence it's safer. It has its negative sides too, adding to unsprung weight reduces suspension responsiveness which means more air time which is not good.
So under the line, if you put all the 968 turbo S equivalent parts under the car, you can ride on 18's with factory 'blessing'. And for 944 TurboS and 89- turbo owners that shouldn't be too hard.
The absolute best performing factory made street legal version of 944 (968TS) has them.
The "best" for what exactly ? and who said it's the best apart from you? and for what the track ? the road/street?
it's only rare because of it's price
It's rare because they didn't make 300,000 of them only 20!
stability of car greatly improves with less or harder sidewalls. That is why all the modern cars have big wheels.
Your Kidding !! i mean I do understand why and how so many Car enthusiasts are so (Pulled in) Guided and misguided with all the Racing derived marketing, Touring car large wheels and as you mention the trend for NEW car's to have Big wheels, but this is all because of Cosmetic Looks and Sales pitches, not because large sidewall tyres are unstable !
You can put 40psi in a 215/60/15 and it'll be a very stable stiff tyre.
When you loose control of the car it is usually because of the uncontrolled sprung to non sprung movement. The less this movement is split between tire/wheel and sprung/non-sprung parts of the car the easier it is to regain control of it. Hence it's safer.
For Street use, shopping or Racing on the street it's all about Compliance and keeping the Tyre on the ground because there are in some parts of the world many Road discrepancies, Lumps bumps, cambers different tarmac etc..et..
Large Diameter Wheels, & Small profile Tyres are a Nightmare on some Public roads ! It's nothing to do with them just being stiffer and harsh but the above road conditions can make the driving and handling awful because they are too big and wide, you have to (Try) and understand the principles and get out your Head Big is not better, Wider is also no always better.
I know it must be difficult because a Wide *** lowered machine looks KOOL but it's really not the direction for Super fast street driving unless your loal roads are all super smooth and flat?
if you put all the 968 turbo S equivalent parts under the car, you can ride on 18's with factory 'blessing'
What are these parts then ?
Why didn't Porsche choose 18" Wheels for the 968 Replacement ?
the 986 Boxster, they fitted 16's instead.
03-06-2017, 09:58 PM
18" wheels: What's the deal? Porsche says don't, but it seems lots of people do?
