[Cloud9...68]

The other factor I haven't mentioned, which has nothing to do with the impact of wheel selection on how the car performs, is that I hurt my back (herniated disk) a couple of months ago, lifting something heavy at an awkward angle. I had a similar injury about three years ago, so I'm somewhat susceptible to it, unless I'm pretty careful with how I lift things. It's healed now, but it was a long, frustrating process. So, since I'm going to be rotating my tires a lot going forward, I was hoping to find a wheel that's A LOT lighter than what I have now, to minimize the risk of hurting my back again. The ~ 5 lb/wheel delta between the lightest available wheel, and the lightest available Porsche-compatible wheel, is enough to make a difference. It's enough to get me thinking about custom-machined hubs that accept a more common bolt pattern. Or at least do some more research on those hub adapters.

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[flash]

i'm not sure i'd mess with hubs. there are a number of things that might be of issue there.



first and foremost, safety. i'd always be afraid of breaking one, particularly considering that the OEM hubs are already an issue. that's why the M030 hubs are beefier.



second, i'd be thinking about the cost relative to benefit. i doubt you will find a wheel that will hold up to track duty of a 3000# car at less than 17lbs. that's only a 2.5# difference. not the end of the world. worth looking around, but failing something being available at a reasonable price, i think there are other battles better fought.



keep in mind that i have always been the one harping about wheel weight. but even i made the decision to go a bit heavier, so as to have a wheel that would not fail. that being said, i also slightly dented one of them on a pothole in pennsylvania, and would not likely have done that with a cast wheel.

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[Inkedupfatboy]

I am not sure this is a solution, but what about machining new axles that have a more common bolt pattern at the hub? It might cost less to have two axles made than 4 wheels?

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[fleetwood]

here are a few avail from a UK site 17x9 w/ 5-130 bolt pattern.



http://www.performancealloys.com/alloy-s...0&PCDID=35





Re: the wolfrace ones, it says -- "All 2013 Track Ready wheels are available with both a large 'cover plate' centre cap and a small centre cap leaving the bolt holes exposed. Pro-Lite can be drilled to suit most four or five stud fitments, offset and centre bore can also be adjusted."

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[EEZATOY]

You can always email Wheel Enhansement to get the weights of their available wheels in the size you are after as I recall some of the Forgeline and Fikse weren't to heavy - when I was shopping for 17" wheels they always responded quickly the information (I ended up with Kinesis Super Cups (used) in 8" & 9" - IIRC they ran about 20# without tires)

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[Cloud9...68]

[quote name='Inkedupfatboy' timestamp='1385054003' post='152668']

I am not sure this is a solution, but what about machining new axles that have a more common bolt pattern at the hub? It might cost less to have two axles made than 4 wheels?

[/quote]

I don't follow. The wheels bolt to hubs which connect to the spindles via the wheel bearings, and each hub is independent. What you're describing sounds like something that would apply to a car with two solid axles.

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[flash]

one of the reasons that wheels for our car are heavier than what you might find out there for others, is our offset. they advertises wheel weights for the shortest of offsets. we have quite a bit of hub area, so they are heavier. if you were able to get real weights, with our offset, i think you would find that even the lightest models are not that much lighter.

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[Cloud9...68]

I was wondering about that, and am planning to make measurements to enter into the wheel clearance calculator. What is it about our cars' hub/spindle/caliper design that forces us to larger offsets?

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[flash]

shorter hubs and axles. they chose to have the distance made up at the wheel, rather than the axle or hub. for example, if we had longer rear axles, the rear wheels could have less offset.

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[Inkedupfatboy]

[quote name='Cloud9...68' timestamp='1385059290' post='152676']

I don't follow. The wheels bolt to hubs which connect to the spindles via the wheel bearings, and each hub is independent. What you're describing sounds like something that would apply to a car with two solid axles.

[/quote]





Maybe - I don't know what is there as I have never taken it apart - maybe just make new hubs...I am just trying to think outside the box.

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[Bulti]

But why would Porsche choose to use shorter axles and larger offsets? Does that have any advantages?

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[flash]

probably has to do with interchangeability. they love to share parts and tooling. it's that or cost.

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[Cloud9...68]

As I think about it, the idea of using hub adapters makes more and more sense. They do make them in sizes that would allow the use of more popular, much lighter, and stronger forged wheels than are available for Porsches. And the fact that they would effectively make the hubs stick out farther would allow the use of smaller offset wheels. This would negate much of their weight penalty, which is all at the hub, anyway, and therefore not as important as the weight at the outer periphery, as Flash has pointed out.



I am concerned about whether adapters would be safe to use in a track application, so I'm looking into that, and have sent an email to a manufacturer of adapters. I don't see why that would be an issue, though; if anything, doubling the number of studs would seem to improve safety, rather than compromise it.



But on the flip side, the fact that my current Enkei NT03's obviously use a 5x130 mm bolt pattern would, I assume, limit their marketability to just the Porsche community, so they may not be as easy to sell as I had originally thought.



There's a lot more to this idea of swapping out my wheels than I had thought! But I'm definitely learning a lot.

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[flash]

most sanctioning bodies won't even allow spacers. i don't know of any that allow adaptors. this is because they are not safe. granted, you won't go through that process for a DE, as those guys let all sorts of stuff slide, but if you truly are worried about safety, i would not use adaptors.



the mantra here was "save money". i think following that, and merely choosing the lightest readily available and replaceable wheel, is the most logical decision. even if you could get them approved, and even if they could be shown to be safe, adaptors add more cost. so does a super lightweight wheel. you can snag a set of 9" 993 cups for under a grand. i don't think that any setup with a wheel that is lighter after factoring in adaptors, plus the cost of the adaptors, will be less expensive.

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[Eric_Oz_S2]

I wouldn't use adaptors. I do use (small) spacers with longer studs.



Really, there is enough choice of wheels out there to run Porsche offset/PCD. I know you want to run 17", but you have a much better choice of tyre and wheels with 18's. There are a lot of light 18's like Oz, Team Dynamics 1.3, Enkei's. Why not run Hoosier R6 or Hankook twin grooves? If you're going to change wheels on the track you may as well use decent tyres. They are very forgiving and have awesome grip. Just a thought.

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[flash]

the tire weight is one of the 2 issues he is trying to resolve. the 17" tire is much lighter, and also gives him a smaller outside diameter, which will make the car faster. even the lightest 18s out there with the lightest tires out there are still heavier than the average set of 17s, and mostly at the outside, which seriously hurts.

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[Cloud9...68]

As I said earlier, my immediate primary goal is to cut the operating cost of using my car for track day sessions, which will allow me to have more seat time, which is the single most important factor in improving my driving. I bought a staggered 18" set-up based on the advice of several very experienced and successful racers and builders, but I now regret that decision, because 18" tires are much more expensive than 17", and the fact that they're staggered means I can't rotate them front to back, which will result in my throwing away tires before they're fully worn out, further increasing the effective operating cost.



As long as I'm planning to go to the trouble to changing out my wheels, it would be nice to get the lightest, strongest wheels I can find for a reasonable price, both to help the car go a little faster, and to make it easier on my back when I do the frequent rotations the square set-up will allow. The fact that the car has an oddball bolt pattern severely restricts my choice of wheels, so I view hub adapters as a potential way to increase my wheel selection. Flash, I looked through the rules of multiple classes in NASA, and couldn't find any mention of hub adapters. They do mention spacers, but only in the context of staying within the prescribed track width limits. Maybe PCA bans them, or I just missed it, but I did searches with all the relevant key words, and couldn't find anything. I'm just not understanding how hub adapters negatively impact safety, since they're just a solid ring of billet aluminum which bolt to the hubs via the existing studs, and then provide studs for the wheels to bolt to. So, you get twice the number of studs. But I'll continue researching this subject, as the last thing I want to do is compromise the safety of the car.



As far as Porsche-specific wheels, yes, if I could find a set of 17 x 9's for around a grand, that could very well be enough to stop all thinking about this nonsense of super-light forged wheels in a different bolt pattern. I assumed that anything with the Porsche name would be outrageously expensive, but apparently not. However, at that price, they'd have to be used, right? And I believe all Porsche-specific wheels are cast, rather than forged. And I just checked the weights again, and they all look like they're north of 20 pounds, which is quite hefty compared to several non-Porsche wheels. But as Flash said, one has to pick ones battles, and compromise where it makes sense.

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[Eric_Oz_S2]

I don't understand why the staggered setup affects tyre life. Of course you can't swap front to rear, but you can flip them - in fact you should always flip track tires as they wear to increase life and deal with outer shoulders wearing first. Yes, if you have directional tyres then you shouldn't run them backwards if you are driving in the rain. If you are really concerned about cost, why not run 16's - are your brakes too large to fit them?

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[Inkedupfatboy]

Yea, I think he said his brakes were too large for the 16's...



I am really surprised at the apparent lack of racing wheels considering how much Porsche races...Why not call Brumo's or someone and ask what they use?

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[Cloud9...68]

Eric,



The problem I'm running into with my staggered set-up is that my front tires tend to wear out a lot faster than my rears, at least at the very technical track where I've done most of my driving. So I'm faced with either throwing away very expensive large 18" rear tires before they're fully worn out, or replacing my fronts more frequently than my rears, and therefore running with different "age" tires on the car at the same time, which strikes me as maybe not the best idea (unless that is a myth, like the inability to swap "directional" tires side-to-side). And yes, I don't think 16" wheels will fit over my Turbo S calipers. Overall, it just seems like a square 17" set-up represents a sweet spot in terms of cost and wheel/tire availability (at least if it weren't for Porsche's use of a bolt pattern that nobody else uses <img src="/forum/images/smilies/968/mad.gif" class="smilie" alt="" />).



In your post #35, you mention several non-Porsche wheels, but do you know for a fact that any of them come in a 5x130 bolt pattern? The only non-Porsche wheel I'm aware of so far that does is the Enkei NT03 that I have now. If only the affordable, 16 lb RPF1 did...

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