I’ve got an ‘88 and a set of C6 wheels. The rears are 19s and touch the sway bar. I’ve read of guys using spacers but I tried a set of small spacers (about 1/4 in) and the lug nuts won’t thread on. I’m assuming you guys with spacers swapped to longer studs? Anyone know what size spacers and which studs to order?

 

On the back-side of a wheel is cast the width and offset. What is the width and offset of the wheels for the rear? You might mention the same information for a front also.Years ago the GM longer studs were very inexpensive. These days they're quite expensive also.

 

Fronts are good to go as is.

 

If you're interested in 'placement' of wheel/tire in the wheelhouse your .250 mentioned won't work. That's the only reason for my question. Seldom have I ever seen mention of a .250 working. To put the 'outer rim edge' where your stock wheel is would require something just short of 17mm so if 'placement' is important you would need something near that dimension and of course wheel studs. I don't know how you might feel regarding the 'spacer/adapter' style product but it's likely less expensive and certainly requires less effort. Those would be an 'off the shelf' product in 19mm OR 3/4". Your wheels have a depression between wheel stud bores so install of adapter/spacer style is generally very straight forward. I'm NOT promoting the use of them but just felt a mention is required.

There's a GM stud that used to be very inexpensive, GM# 22551491 (it ain't that way now). Those would accommodate a pass-through spacer of the required thickness for wheel/tire placement. People buy the ARP product also. I've no experience with their product, I used the GM product in '04 I believe 15+ years ago. there's quite likely less expensive wheel studs out there also.

Others will likely have comments.

 

None of the following invalidates anything in the post above. Just some alternatives to consider. You need no more than 8" back spacing to clear the inside on the rear of your 88. Those C6 rears have 79mm offset and 8.61" backspacing as is, which is why you have interference even with 0.25" spacers. The 3/4" spacer mentioned above will get you 7.9" backspacing, and that will absolutely work and give you the outside edge at the stock location, as mentioned. OTOH, you have room to go further out if you prefer. A 1" spacer would effectively give you 54mm offset and 7.63 backspacing, with the outside edge still inside the fender. It's largely a matter of preference.

Wheel adapters are an option and many have used them successfully. While I've never heard of one breaking, they strike me as having far more ways to fail than a simple spacer. There is absolutely no reason not to use a 3/4" or 1" spacer if your studs are long enough. They cannot possibly fail, as they have no stress risers - they are in pure compression and hold the wheel to the hub face by friction force, just like the wheel without any spacer. I used ARP long studs and they are great. I never tried to install them with the hub still on the car - the car came to me with them installed, and the only time I swapped them out was when I replace the hub/bearings. So I can't comment on how difficult the job is, but I've seen others say it can be done one the car.

 

So to confirm, longer studs and a 1” spacer will do the job?
-thanks guys for the info!

 

Absolutely, yes.


That's a really ignorant and alarmist post and does nothing to help advance the knowledge base here. You're absolutely wrong. Here is an engineer's explanation of how spacers work, and why they are 100% safe: https://www.maximummotorsports.com/t...s_spacers.aspx. Please don't post stuff like that without understanding the issue.

 

https://www.summitracing.com/parts/a...YaAugvEALw_wcB

Looking at these from Arp.

 

I don't know of any appropriate length wheel studs that will work for the use of a 1" pass through. There's much to measure before buying!!! MUCH!!!! Don't order spacers before confirming an appropriate stud. The GM studs can be installed 'on the car' with simply grinding a chamfer on the stud head.

Measure the length of the stud used on the car now to the rotor, add 1" and then measure your wheel to see the required length additionally to use nuts with 4 threads exposed. That would get you likely a required/appropriate length stud length to shop for. 19mm or 3/4" I believe are no problem.

*** I personally feel 1" is excessive and FOOLISH!!!
.

 

Your constant referral and attributing the statements in that link to 'an Engineer' is maybe as alarmist and ignorant as the post you criticized!!

 

Thank you! People love bashing spacers/adapters on here, "My buddy ran em on his S10 32 years ago and HE DIED!!!". No... he didn't...

 

It's alarmist to post the facts about how something works? Maybe you should look up the word "alarmist" and then consider the following paraphrasing of the following dialog:

1. "Oh my god if you use spacers you'll lose control and die!"
2. "Actually,the friction from the clamping force is what hold the wheel to the hub, and nothing about that changes if you add a spacer between them. Therefore spacers are totally safe as long as your studs have enough thread."

If you believe that only #2 is alarmist, or both are equally alarmist, then go back and re-read the definition!

If you have a problem with the source I cited, feel free to bring it up. I'm inferring that you question the qualifications of the author? Well, the author is Jack Hidley and he is indeed a licensed engineer in California. He has a long history of automotive research, aftermarket parts design, and technical assistance; not to mention that he was lead engineer for NHT speakers for years (maybe decades?). He has credentials.

Why do you think 1" spacers are "excessive and foolish?" And why would you prefer a 3/4"-thick ring of metal that requires five tapered holes for studs and lug nuts plus five wheel studs pressed in, in an alternating pattern with tension between each pair; over a 1" ring that's held in simple compression between two other pieces of metal?

 

I didn't 'PROMOTE' the adapter - I said I felt 1" was EXCESSIVE & foolish!!! I don't/didn't see you pick an appropriate wheel stud for the OP!!! Do you got's one 'in the pocket' maybe?

A 'SPEAKER GUY'? sure - I give a 'rat's a$$' - it's an 'opinion piece' as are your comments and mine as well. I had pass-through done for me and I've no regrets. The fabricator has since passed so I wouldn't suggest a vendor either.

 

And I asked you why you think a 1" spacer is excessive and foolish? ATFQ.

I didn't think I needed to add anything to what you advised on picking a wheel stud.
No, not "a speaker guy." A professional engineer with formal training and decades of experience in automotive applications of engineering, among others. Did you miss that the first time I wrote it? He also has experience in track and competition with his own cars.

I'd quote other references on the same topic instead of the same one over and over, but I haven't found anything else on the topic. Maybe I wouldn't have to quote it all if so many people didn't fundamentally misunderstand spacers and wheel attachment! And no, it's not an opinion piece. It's a essentially a "white paper" on the facts about how wheels are actually held in place on a hub and how spacers work in that context. There is a right and wrong here: not everyone's beliefs here are valid. What are your credentials, and based upon what facts do you think a 1" is foolish and excessive?

Good to know that you're actually using spacers. So basically, you and I are on the same page and you're just up my *** because...reasons...as usual.

 

Reasons ...as usual? Maybe I care NOT what you say but that's sill an 'opinion piece'

This particular install for the OP you suggested 1" and he bought immediately into it!! If the OP is happy with his 8.5 @ 56 for the fronts why is it that you feel it necessary to modify the wheel/tire placement in the rears? That in itself justifies both the 'silly/foolish & excessive'!!! I don't know that there is or ain't a wheel stud that would accomplish the 1" install but I believe it's certainly more $$, a difficult find and maybe a more difficult install. Do I know? NO - but I didn't send the OP on the hunt.You hinted just buy the 1" spacer and all's well!!!

Next you'll tell me and pass on to others that there's no need to be concerned with hub & wheel concentricity when using spacers. My guy did mine with 13mm stud bores that were hub-concentric and the spacer also to the wheels. It was the only way he was interested in doing them!!

 

Well now I can't tell if you're even serious or just trolling. The reason for modifying the wheel/tire placement in the rear is that his wheel of choice is 10" wide with 79mm offset and about 2/3" too much backspacing to fit at all. So he clearly has to add some sort of spacer/adapter to get rid of at least 2/3" backspacing. You suggested 3/4" and I agreed that would fit fine, but suggested also that 1" is a good option. BTW, it puts the center of the contact closer to the original center than the spacing you suggested, so you're the one suggesting a "modified" wheel/tire placement," not me. But anyway, you're arguing over 1/4" one way or the other when both will clearly work.

There is. As you said, he has to find the length of the OE stud and find the ARP stud that has at least 1" additional length. They have several lengths to choose from, and some are even longer than he'll need.

I hinted at no such thing. I was very clear that longer studs would be required. Will that be an additional hassle the first time out? Yes. Will it be more money? I'm guessing not, since a spacer is way easier to make and should be cheaper than a good quality adapter. On the plus side, it will be lighter and less likely to fail than an adapter, and more universally adaptable to wheels that may not have deep enough pockets to accept the wheel studs when using a 3/4" adapter (which will have significant stud length exposed).

So you suggested 3/4" is all good and 1" is "foolish and excessive." You're on my *** about 1/4". Actually, I don't think you even know why you constantly feel the need to challenge me and call me out. I think you've decided you don't like me, and that you're going to contradict me even when I'm agreeing with what you wrote. This is a recurring theme with you in one thread after another.

 

It's not opinion - it's empirically tested fact. Again, that's an engineer with decades of racing experience and plenty of testing and research behind what he says. What are your credentials? Oh, and unlike you I'm pretty sure Jack even knows how to use an apostrophe for possessive nouns.

No, they don't. And if you read the article I cited, you'd understand why: the studs don't hold the wheels radially, they only clamp the wheel to the hub with tension. There are no bending loads on wheel studs, only tension forces! And if there were, then the adapters that you think are so much safer would add just as much extra leverage to the studs, because the leverage comes from the distance between the hub face and the center of the tire's contact patch. You have no understanding of the forces involved in fastening a wheel to a hub.

Why the hell would a spacer need to be hubcentric? It has nothing to do with locating a wheel radially on the hub. And are you saying that only hubcentric wheels are safe? Because a century of results certainly say otherwise. But sure, a wheel spacer that's thick enough can be made hubcentric. Literally from the same site that I already referenced, here is what that looks like: https://www.maximummotorsports.com/3...ang-P1404.aspx. You are certainly proving that you don't know what you're talking about.

Jack isn't a "sales boi" at all. He is an engineer who designs and tests parts - he doesn't sell them. He has literally tested the clamping force and friction of hubs and wheels - he isn't just imagining the information. Again, you just have no idea who or what you're talking about.

Bwaaahaaaaahaaaaahaaaahaaaaahaaaaahaaaah aaaaahaaaaahaaaahaaaaahaaaaahaaaahaaaaah aaaaahaaaahaaaaahaaaaahaaaa!

 

ORLY? As I already pointed out, hubcentric spacers are readily available. I mean, I actually linked you directly to them - did you even read my post? So if that's your only concern about spacers, then there's no concern at all. I would think that anyone who claims to know as much you do would know that hubcentric spacers are a thing. Also, not all adapters are hubcentric: just like with spacers, some are and some aren't. So there's no distinction at all here. You're blathering about nothing.

If a "wheel becomes slightly loose," then you failed at tech 101 because your lug nuts weren't properly tightened. No wheel is safe if the lugs aren't properly tightened, because then you don't have clamping force to keep it located on the hub. That's a stupid reason to insist that spacers are bad. Seriously, all those sanctioning bodies you mentioned that supposedly ban spacers aren't going to bother checking for spacers on your race car if you show up to tech with loose lug nuts!

But guess what? If you have a hubcentric wheel on a hub, or on a hubcentric adapter, or on a hubcentric spacer; and you leave the lug nuts loose, the studs can still shear off. The shear force won't come from centrifugal force (seriously, WTF are you talking about with that?), at least not if the car is actually rolling on the ground (as opposed to the drive wheels being up in the air and spinning unloaded). The shear forces will come from: 1) the weight (load) of the vehicle at that corner bearing vertically across the face of the hub, and 2) the rotational force of the hubs during braking or acceleration. Hubcentricity can help with #1 up to a point, but not with #2. Also, the more a lug nut backs off, the the more that cornering forces (lateral acceleration) at the contact patch will act to pull the wheel mounting surface away from the hub face and impose various loads on the studs/nuts/seats, and hubcentricity can't do anything to help that either. So the lesson here is to, you know, properly torque your lug nuts. If you are preoccupied with hubcentricity but don't bother to properly tighten your lug nuts, then you're letting paranoia divert your attention from what's really important: kind of like spending all your time at home disinfecting all the surfaces while you drink milk that was left out of the refrigerator overnight.

Really? How could you possibly attribute any failure to a spacer? A spacer is just a piece of metal in compression - it can't possibly come apart. It could only possibly fail if it was so soft that it actually compressed due to the clamping force and cause the lug nuts to come loose. But since they are made of steel or aluminum (i.e. the same thing wheels are made of), then that can't happen. Your whole argument is predicated on someone driving around with loose lug nuts. But if there's a failure due to that, then the cause of the failure was improper lug nut torque, not the spacer. OTOH, an adapter could fail if one of the secondary wheel studs pulls through or if the ring cracks due to the ten points of opposing tension imposed on it, along with the multitude of stress risers it must have.

​​​​​​That's actually an interesting point: the adapter has far less clamping surface than a spacer because it has to make room for a second set of studs and nuts. However, I think that's probably not much of an issue, because if the coefficient of friction stays constant with increasing clamping force, and if the clamping force (lug nut torque) stays constant, then the total static friction force will remain constant regardless of surface area - only the PSI on the surface will change. The only way this can be a problem is if the coefficient of friction reduces as clamping force increases, which I doubt (but I'm open to someone showing that it does).
​​
So to sum up, you think spacers will cause people to die because they aren't hubcentric, and hubcentricity is critical because there's an increased risk of wheel separation if you drive with loose lug nuts. But that's silly because:

• Spacers can also be hubcentric, and not all adapters are hubcentric.
• Hubcentricty only helps with one of several failure modes if your lug nuts are loose.
• Don't drive on loose lug nuts, dumbass.
• There are literally tens of millions of cars (maybe hundreds of millions) throughout history that have not had hubcentric wheels and never lost a wheel.

So if the OP wants to drive around with loose lug nuts, he just needs to make sure he buys hubcentric spacers so he won't die. Satisfied?

 

He doesn't show up in DCA. So not sure he's licensed in CA.
The Jack Hidley that worked for NHT seems to have graduated Cal Poly with a degree in Electronics Engineering. Not sure that qualifies him on the physics of wheel spacers.

 

I've lost interest in participating. Good luck with your cars, Peace out.