Are 18in wheels safe
02-07-2006, 02:27 PM
#1
Burning Brakes
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Are 18in wheels safe
I recently posted a thread about changing my suspension and the topic of 18 in wheels came up. hawk stated PNA has warned against using them unless you have a turbo. Potential danger of fracturing the front studs or fracturing the rear suspension. I have 18 in wheels and love the feel and have no rubbing issues. I installed 18 in wheels on my SL500 which was also originally equipped with 16 inch wheels and loved them too. Are there a lot of 18 in users out there? Any asociated problems? Not sure why this would be so much different than using spacers to get the wheels flush with the fenders. 
02-07-2006, 02:37 PM
#2
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Good question Don, I’m interested in hearing the same info. It seems as if the "18 inchers" have taken over the market... I’m interested in the 18" BBS (one day)...
BTW, your wheels a very special... Falke ?...
Marc.
BTW, your wheels a very special... Falke ?...
Marc.
Last edited by MARC A. 964 C4; 02-08-2006 at 01:38 AM.
02-07-2006, 03:25 PM
#4
Adrian, please correct me if I mis-speak, but, if I recall correctly, Porsche did not recommend the 18" wheels on a non-turbo 964 due to the strength of the supporting components on the suspension. Aside from the rubbing issues, I don't even know if Porsche tested the 18" wheels on a NA 964. Without the performance information of the increased loading onto the suspension, it may be risky.
02-07-2006, 03:44 PM
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Burning Brakes
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I can't say anything about the use of 18's on the track, but it seems pretty crazy to associate suspension and stud fractures with the addition of one inch on the radius of a rim. The way I see it, if the car was designed to withstand lateral gravity force loads, pot holes, curbing and soforth, as you might find, or encounter on a typical highway or auto course, how are 18 inch wheels v/s 16 or even 17's going to cause all these problems? If these accusations are true, then it doesn't really say much for the quality or engineering efforts that should be, none-the-less, expected from an economy car.
I think whoever is making this crap up up is either trying to keep a (Singular) incedent from occuring that might send panic amung Porsche owners. Or maybe it's all just a bunch of hooplah.
With that said, I've been running eighteens on my car for over a year now with no issues. As a matter of fact, the only problem I have is trying to keep my right foot from going to the floor all the time.
Duncan
I think whoever is making this crap up up is either trying to keep a (Singular) incedent from occuring that might send panic amung Porsche owners. Or maybe it's all just a bunch of hooplah.
With that said, I've been running eighteens on my car for over a year now with no issues. As a matter of fact, the only problem I have is trying to keep my right foot from going to the floor all the time.
Duncan
02-07-2006, 03:49 PM
#6
Burning Brakes
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Chris, looks like they were recommended for the turbo s and turbo 3.6S. Also looks like 17 in wheels are okay for any 964 but Porsche also approves of 18 in N rated tires as well.
02-07-2006, 03:50 PM
#7
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IIRC, the other issue I seem to remember regarding 18" wheels was increased vibration causing cracking of the rear side windows.
No, I can't post a source (as I can't remember it) but someone else may have come across the same thing.
Marc
No, I can't post a source (as I can't remember it) but someone else may have come across the same thing.
Marc
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02-07-2006, 04:09 PM
#11
Duncan, I don't think it's the extra inch that could cause the problem. I think it would stem from the increase weight (load) on the suspension components. Granted, lots of the high end 18" wheels can be fairly light weight, but, generally speaking, bigger wheel = more mass = more load on the suspension components.
02-07-2006, 04:12 PM
#12
Three Wheelin'
This issue comes up so often - there must be stacks of hstory if you do a search.
I'm with you, Duncan, 100%!!
The 3.6 Turbo was, in fact, fitted with the Speedline 18" wheels as standard but all other N/A 964s were only "approved" with 17" with an associated change to the steering stops to eliminate wheel arch rub.
That said, I believe Porsche NA were careful to issue a Technical Bulletin effectively outlawing the fitment of 18" wheels after a few episodes of axle failure during the running of Cup cars with racing slicks on 18" wheels. The amount of common ground between a Cup car running racing slicks and a N/A car on the road is very small. I have been running 18" 8.5J/10J wheels on my car for more than 2 years now with NO issues at all. Sure, the ride is fairly harsh - what would you expect - but it feels good, it looks good and it suits me.
The fact that there are 18" N-rated tyres doesn't prove a thing since they are approved for fitment to the Boxster and 996. Some 993s were approved for 18" wheels also. I run 225/40 and 265/35 Yokohamas on mine.
I'm sure Adrian may chime in with the official word - and he'll tell you that HE has 19" wheels fitted to his 964!!!
Best regards
Dave
I'm with you, Duncan, 100%!!
The 3.6 Turbo was, in fact, fitted with the Speedline 18" wheels as standard but all other N/A 964s were only "approved" with 17" with an associated change to the steering stops to eliminate wheel arch rub.
That said, I believe Porsche NA were careful to issue a Technical Bulletin effectively outlawing the fitment of 18" wheels after a few episodes of axle failure during the running of Cup cars with racing slicks on 18" wheels. The amount of common ground between a Cup car running racing slicks and a N/A car on the road is very small. I have been running 18" 8.5J/10J wheels on my car for more than 2 years now with NO issues at all. Sure, the ride is fairly harsh - what would you expect - but it feels good, it looks good and it suits me.
The fact that there are 18" N-rated tyres doesn't prove a thing since they are approved for fitment to the Boxster and 996. Some 993s were approved for 18" wheels also. I run 225/40 and 265/35 Yokohamas on mine.
I'm sure Adrian may chime in with the official word - and he'll tell you that HE has 19" wheels fitted to his 964!!!
Best regards
Dave
