As I've been contemplating switching out my current staggered 18" wheels for a square 17 x 9 set-up, I've been doing a lot of research. Since this is primarily a track car, my priorities for wheels are roughly as follows:
1. Weight
2. Weight
3. Weight
4. Don't want anything that looks TOO ricey
5. Weight
I found a site that seems to be reasonably up to date which lists wheel weights, and have found a few in the 14.8 - 16 pound range. But then I remembered something the installer at Discount Tire told me when I bought my last set of tires - that the 968 has a very unusual bolt pattern, shared by only a few other Porsches, and basically nothing else. Sure enough, the 968's bolt pattern is 5 x 130 mm, meaning an imaginary circle formed between the centers of the wheel studs has a diameter of 130 mm, and it is an EXTREMELY rare pattern.
So, does this mean that only a tiny fraction of the wheels made can fit the 968? The lightest wheels definitely don't show to be available in a 5 x 130 mm bolt pattern. However, neither does the Enkei NT-03 M that I currently have, and they obviously fit on my car.
So, is this as ominous to a track junkie like me as it sounds? Are more wheels available in our bolt pattern than it appears, maybe because the wheel manufacturers don't want to list every possible combination of bolt pattern and offset? Is there an adapter that can somehow convert our bolt pattern to something more common that doesn't add too much weight? The few wheels that do show up in a search on Tire Rack in a 5 x 130 pattern weight a ton - more than my current wheels, which almost completely defeats the purpose of changing.
It strikes me as very odd that I've never read about this before, and yes, I did a search, here, as well as on other sites, and on Google. Thanks.
What would the cost be to have something custom made - Foose does one offs for all his cars...Or does someone make a billet wheel then drill bolt pattern to requested spec?
I checked tire rack a while back and there were LOTS to choose from.
Remember, tire rack and Summit both have warehouses here in Reno, and you can save a bit coming over to pick things up if you are in the SF/Sac areas.
Speedy,
Yes, I know, many other Porsches use the 5 x 130 bolt pattern.
MCL968,
When I do a search on Tire Rack under the 968, only three wheels come up, and they're all real heavyweights. So I tried searching under the 911 and 928, and all that comes up are 18" wheels, for the years that even show anything (for the 911, strangely, many years show no wheels available).
The wheels that appeal to me most of the Enkei RPF1 (16.0 lb in the 17 x 9" size), and the Volk Racing CE28N (a feather-light 14.8 lb, but quite a bit more expensive than the Enkei). I don't see a 5 x 130 mm bolt pattern listed for either of these wheels.
5 x 130 is not a common pattern for wheel manufacturers. it isn't ford or chevy. they know that porsche guys are a picky bunch. it's also a small market. so, not that many dip into it.
you can have them made custom. for example, i believe HRE still does it.
[quote name='Cloud9...68' timestamp='1384987338' post='152606']
Speedy,
Yes, I know, many other Porsches use the 5 x 130 bolt pattern.
MCL968,
When I do a search on Tire Rack under the 968, only three wheels come up, and they're all real heavyweights. So I tried searching under the 911 and 928, and all that comes up are 18" wheels, for the years that even show anything (for the 911, strangely, many years show no wheels available).
The wheels that appeal to me most of the Enkei RPF1 (16.0 lb in the 17 x 9" size), and the Volk Racing CE28N (a feather-light 14.8 lb, but quite a bit more expensive than the Enkei). I don't see a 5 x 130 mm bolt pattern listed for either of these wheels.
[/quote]
I understand, there are few offerings in the 17" size. I tried a couple of other places, and I even googled "porsche 17" wheels", which produced a few more options. Thus far I am still running the stock 16's. I hope to find some 17's I like before summer, assuming I get this gas smell to go away!
I checked HRE's site and it appears that they only make custom wheels (jeez, that sounds expensive) in 18" and up. The mind is seriously beginning to frown here...
hmmm - that's new. they used to make custom 17s too. i think i would call.
Also, I just found that there are such things as hub adapters, to convert one bolt pattern to another. It adds weight, of course, and effectively increases the offset by the thickness of the adapter, which looks to be pretty substantial, which will complicate the wheel selection/clearance issues even more. Sometimes I wish I had bought a Miata... I'll give HRE a call, although the cost of anything with the word "custom" in it is sure to make one reach for the smelling salts.
lol - yeah - they will be over a grand each
"As I've been contemplating switching out my current staggered 18" wheels for a square 17 x 9 set-up, I've been doing a lot of research. Since this is primarily a track car, my priorities for wheels are roughly as follows:..."
Cloud,
Food for thought:
There are lots of wheels available for the 968. If you're looking for new check out Wheel Enhancement, Lots of used wheels in "Panorama" and "Excellence" web sites and the local PCA group. If buying used make sure the the wheels have been thoroughly inspected by a qualified shop. Keep in mind that wheels used for track days take a beating from more frequent mounts and demounts so cosmetics are can be a secondary consideration. You might also consider using the 968 16" wheel and used 225/50R16 on all four corners. Bridgestone now makes the RE11 in a 245/45R16 but I don't know about front clearance. There was also a 16X9 wheel used on the 88/89 944 turbos that was forged and very light but very hard to find. A 225 on an 8 inch wheel is nearly ideal from a wheel width to tire cross section
ratio, i.e. the wheel width is 90% of the tire cross section.
Good Luck,
p.s. - my wheels were custom made by them. as i remember the cost on those was about $1300 each. probably not in anybody's budget, considering that they are still 20# front and 22# rear, and 18s.
however, as i remember the C70 wheel they make in a 17 could be done in the right offset, and was less than 17#. cost is still likely to be about a grand each, so maybe still not in the picture.
gotta pic your battles. i think i would run the 993 cups and call it a day. maybe add spacers, as much as i hate them (of course lengthening the studs), but just to push the rim out a bit and give a better stance. they are light, relatively easy to find, and not terribly expensive. the tire is going to make a lot more difference than the rim anyway, when it comes to weight. outer mass matter more than inner mass.
Thanks to everyone for their inputs. Keeping in mind that my primary goal with going to a square 17" set-up is to allow more seat time by saving money on tires, $1K+ per wheel is pretty much a non-starter. But my other goal besides saving money is to serve as an impartial test bed to evaluate the pros and cons of factors such as wheel diameter (and its impact on rotational mass and effective final drive ratio), tire sidewall height, tire width, tire brand and category, etc. Since I'm not racing competitively, I'm happy to share what I find with the community, hopefully benefiting people and bringing some meaningful data to the discussion. Finally, since I know everything is a trade-off, and I'm going to be giving up some grip by going with slightly narrower wheels overall, I want to offset this by going with as light a wheel as I can find. Plus, it's just plain cool to see people in more expensive and faster cars marvel at how fast my 20-year-old 968 can lap the track. It's very disappointing that the fact that Porsche insists on using a bolt pattern that nobody else does, my choice of wheels is severely limited, particularly in the 17" diameter.
Tom,
I've looked at Wheel Enhancement. The vast majority of their wheels as 18" and above, and they don't list the weights. It seems that whenever I've seen the weights of Porsche wheels listed, they've been disappointingly heavy. My current wheels are 19.5 lb in front, and 21 lb in back, which are actually fairly light for 18-inchers. I guess I feel that if I'm going to go to all the trouble of changing out my wheels, I want to make it worth my while by going with something significantly lighter than what I have now. Doesn't look very promising at the moment, thought, but I'll keep looking. If anybody has a credible source of the weights of 17" wheels that fit on Porsche, please reply with it. As far as 16" wheels, I'm not sure they'll clear my massive 944 Turbo S calipers, so I think 17" is my best option. Plus there are still relatively low profile 17" tires made - I want to stay at an aspect ratio of 40 or below.
Flash,
Yes, I understand that the outer diameter is more important than the inner, although since most of the weight of a wheel is concentrated at the rim, I would think the weight of the wheel is still pretty important, at least more so than that of the lugs, adapters, or spacers, right?
Edit: I found a list of Porsche wheel weights. Ugh. Most are 20+ pounds, with the 993 cup the lightest at 19.5 lb in the 17 x 9". REALLY makes me pine for the 14.8 lb Volk Racing CE 28N's. If only...
I am curious as to why manufacturers don't list the weights of the wheels more often.
[quote name='Eric_Oz_S2' timestamp='1385032381' post='152644']
Have you tried Oz?
http://www.wheelbasealloys.com/alloy-whe...k/17-inch#
Only 17x8, but there may be other models in wider fitments. Oz wheels are very light and top quality.
[/quote]
I've looked at Oz a little bit, but have found that the widest they come in the 17" diameter is 8.5", they don't appear to come in the 5 x 130 mm bolt pattern, and while they're fairly light, they're not a whole lot lighter than the 18" Enkei NT03's I have now. But, as Inked alludes to, it's very frustrating how much searching you have to do to find all the important information about wheels. Why the wheel manufacturers and distributors don't list the diameter, width, offset, weight, and available bolt patterns on every wheel is completely beyond me. <img src="/forum/images/smilies/968/mad.gif" class="smilie" alt="" />
[quote name='Inkedupfatboy' timestamp='1385039812' post='152647']
I am curious as to why manufacturers don't list the weights of the wheels more often.
[/quote]
Agreed! [color="#006621"]
www.944racing.de/wheelweights.php[/color] has a fairly good list of OEM Porsche wheel weights.
most of the weight is in the tire, not the rim. on a wheel, half of the weight is at the hub and spokes, not at the rim. that's why wheel weight is less significant that tire weight. while losing mass is losing mass, the relative effect of wheel weight loss is far less than tire weight loss. that's why i wouldn't get too hung up on it. sure, get the lightest things your budget will allow, but focus on where the money is best spent, and how maintainable that expense is. if the wheel is hard to come by, it probably isn't the best choice unless you have unlimited funds. similarly, if they are expensive, it will probably mean less seat time, which is also likely not the best choice.