[banderson]

Quick question. if I have the stock 17" cup wheels on my 1992 what size wheel spacers would I need to achieve the "flush" look of the outside of the rim being basically even with the wheel well. Also does ride height effect this much? because the next time I get my car aligned (hopefully soon) I want to have them lower my car a little. I am mainly trying to improve appearance but am interested in what you all suggest performance wise and so on. thanks

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[PorscheG96]

Wow, beautiful 968! Is that Cobalt Blue?



Lowering the car won't affect the offset of your wheels and, if anything, will make the problem worse because the gap between fenders and tires will be reduced and accentuate the offset problem. In my opinion, you shouldn't run spacers greater than 8mm without changing to longer studs and even then you should check the wheel torques more often. 8mm will go a LONG way toward improving the offsets but you may want even more - I know others have done this.

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[banderson]

@ PorscheG96 yes that is the Metallic Cobalt Blue! And I was mainly thinking about lowering the car after the spacers were on, because I agree it would look worse to go lower with the current set up. But 8mm is a good starting number thanks for the input

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[flash]

i would measure and count the threads. you need at LEAST 1.5 times the diameter in length of clean threads. i did this once, and i think i came up with 7mm as the maximum spacer thickness before having to use longer studs, using OEM wheels.

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[banderson]

hmm so I am probably going to need need studs as well then to be on the safe side. It seems like that would be a pain? Flash whats your opinion on the spacer I would need? and is there a certain brand that would have the spacers and studs all together in a package?

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[flash]

lol - my opinion is not to use spacers, ever. they are not allowed in most race groups, and for good reason. pca is the only one i know of that looks the other way like they do.



frankly, if i had to use spacers, and couldn't just buy rims that were the right offset, i would weld the spacer to the rim, and then change the studs



i'll see if i can remeasure tomorrow, and get a real number for the stud length. my problem is that i don't have an OEM rim to measure the material thickness. i know they don't leave you a lot to work with though.

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[banderson]

Your answer doesn't surprise me considering no one really suggest spacers. I'm sure down the road I will be in the position when I can get the rims I want therefore i have no desire to weld anything on my car lol. Is putting new studs on these car much of a hassle? I'm assuming you are going to measure to see what size spacer I could get away with using the original studs.

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[flash]

ok - i got a chance to measure things. porsche did us NO favors here.



using aluminum lug nuts, there is NO room for spacers whatsoever. with steel lug nuts, you can use a 7mm spacer.



the exposed part of the studs are 31mm long

the thickness of the wheel, at the base of the cone, is 10mm



the rule is:

with steel lug nuts, you need a minimum thread engagement equal to the diameter of the lug nut. we have 14mm studs, therefore need 14mm of engagement. that leaves 7mm



with aluminum lug nuts, we have exactly the minimum amount of thread engagement (not likely a coincidence)



i don't care who has done it and "not had any problems". the engineering rules are what they are. spacers are not safe at all using the OEM lug nuts. 7mm is the maximum even using steel lug nuts. after that, you need longer studs.

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[banderson]

well it look like I will be going 14mm all around and get all new studs. Ill have to take before and after pics. thanks for checking that flash! I learned a lot from this actually lol

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[flash]

no worries - happy to help. also good to know that i haven't completely lost my memory, and that i came up with the same answer this time as last time.

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[Krister]

I run 7mm spacers.

I need them to run free from the GT3 brake calipers.

But I would like to have longer studs, are they hard to replace?

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[Krister]

Hasn't anybody replaced their studs?

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[bombfactory]

Flash, assuming the wheels remain the same, does, say, a 15mm spacer affect suspension rate and geometry? Can it make a measurable difference or is it insignificant?

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[flash]

due to the nature of the added weight of the second set of lugs, the suspension will feel sluggish by comparison.



as for geometry, it doesn't technically change the geometry, but it does change how the tire sits on the ground, relative to the hub, which can affect ride height and the leverage relative to the spring rate. this generally results in a feeling of softness and more of a tendency to undulate.



insignificant? no. but, it's not the end of the world either.

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[ds968]

On my six speed I have 20 mm spacers on the front wheels ( a 5mm spacer and a15 mm one ) and just one 15 mm spacer on the rear wheels. The OE studs were replaced by longer, bolt- through steel ones which I ordered at the same time with the spacers . IIRC it was from Vertex auto. I was somewhere concerned about the added 12 lbs from those steel bolts ( the spacers on the other hand are light as a feather ) applied right to the rotating mass, which would be the equivalent of approx 48 lbs added to tne car, but decided the sacrifice was worth it in exchange for aesthetics . Now with the SC , that 12 lbs is not such a huge concern , lol. So I'm going to put the same spacers on my Tip car as well..

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[ds968]

Just ordered some - jeeezus, the prices increased a lot since I last bought those - for the 15 mm size they're now $ 87 a piece .

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