Hub centric

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60jerry

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I've been looking at the Mopar Action magazine article. I understand the concept but when the tapered seat lugnuts are torqued on the wheel, what would a ring accomplish. Seems to me that the ring could do nothing since the lugs and tapered lugnuts hold the wheel solid on the hub or axle andnin only one possible position. What the heck am I missing here? If the ring is made of some really hard metal, perhaps torquing the lugnuts might push (bend?) the lug studs sideways or something but I question that. They're pretty tightly set in the rotor or axle flange.

Jerry
 
Well, I suppose if the metal around the lug holes is seriously beat up, rusted or distorted (and I have seen some bad wheels), you might be able to mount it in an unbalanced position. But generally, yeah, what he said.
 
Simple, the bore of the wheel is used to locate itself hypothetically concentric to the spindle hub i.e. wheel bearing axis. Lugcentric uses the lug openings to locate the wheel on the same premise.

Guess which is easier to control in manufacturing with an acceptable tolerance and make for a safe and acceptable assembly with a wheel, spindle, wheel bearings, hub, rotor or drum, and possible a drive axle and you have 4, 5, 6, 8, 10, 12+ lug studs or lug bolt holes?

So it's not paranoia, it design for manufacturing to achieve a easier to control, manufacturing wise, outcome.

This is all ignoring thermal, shock, any other feature control like flatness, parallelism, and variation of tolerance amongst parts, material indifference, etc. In other words, I'm leaving a lot off the table on the design and manufacturing aspects.

Now, being hubcentric allows to loosen the hole size and locations of the lug holes in the wheels and the misalignment you refer to is made up by minor deflection of the studs. The conical seat again is an easier feature to control to torque against and not have a tight tolerance hole and lug shank and control their positions too. Hubcentric spacers are used by aftermarket rims manufactures to adapt to multiple hub sizes.
 
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With a conical lug nut that mates into a conical seat, hub centric can be thrown out the window. Now, on the other hand, if you have mag wheels that attach with a shank style lug nut, then hub centric becomes critical. Since the wheel has a minute amount of space between the lug nut holes and the shanks of each lug nut, without a hub to center on, there can be endless possibilities of where to position that wheel. So you could say that each style, hub centric and lug centric are both dependent on which type of lug nut is used.
 
RustyRatRod said:
mag wheels that attach with a shank style lug nut, then hub centric becomes critical. Since the wheel has a minute amount of space between the lug nut holes and the shanks of each lug nut,
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Agree.
I bought a new PT Cruiser and installed a set of aftermarket wheels and tires. Had the most annoying shake at speeds over 50 mph. That's when I found out about hub centric rings.Installed a set from American Racing wheels to cure the shake.
 
RustyRatRod said:
With a conical lug nut that mates into a conical seat, hub centric can be thrown out the window. Now, on the other hand, if you have mag wheels that attach with a shank style lug nut, then hub centric becomes critical. Since the wheel has a minute amount of space between the lug nut holes and the shanks of each lug nut, without a hub to center on, there can be endless possibilities of where to position that wheel. So you could say that each style, hub centric and lug centric are both dependent on which type of lug nut is used.
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Thanks to all for setting my mind at ease. I went through thinking about this years ago and my conclusion was the same then. Cone shaped lug nuts and lug holes centers fine if the wheel was manufactured properly. RRR, some years ago I used a set of aluminum slots and I thought then about the slop in the fitment when the nuts were run in to the point of almost stopping all wheel movement and the slop remained. I'd love to have aluminum slots on my '63 wagon (4 1/2" now) and I would try for a set of rings. I'd be in some trouble because I would be reguarly wanting to switch back and forth. I think that all-in-all I prefer steelies and little hubcaps. Right now it's Ford Maverick 14X6 steelies with blank Mercury poverty hubcaps. It'd be really cool to get a set of BBP 14inch mopar steelies. Being marginally brave I think I would cut them apart and reverse the centers for a deeper look and use my poverty hubcaps that were originally on my Dart's 13inch wheels.

I'm happy to hear this straight information from you guys who have described the facts very well.

Jerry in Denver
 
See post #4. You can get a hub centric wheel easily within .001 or less. Try doing the math on 5 holes, 5 studs and the holes they are installed in, not even close. Tires take up the slack, how fast do you want to go?
 
I just went through this exact situation, I bought used aftermarket wheels that were used on 5/8 studs, to use on my 1/2 studs. To do this I ordered shanked open end lug nuts, shank diameter of .687. The problem is the shanks had a bit of play within the hole, I did not feel comfortable with the fit. My axle registers are 2.3", and the new wheels have an opening of 3.25". I had my local machine shop make me some custom rings to properly center the wheel, the fitment is excellent. Now the lug nuts only purpose is clamping. I will post pics after work.
 
....and to be clear, I'm not knockin hub centric wheels like aluminum slots. I have a set I'm going to run on Vixen. As long as the center correctly on the hub, they can have a little play in the direction or the rotating wheel either way and they're still fine. It's the lateral play in relation to the hub they cannot have. In other words, hub centric wheels are usually very application specific, because in this case I don't know if there's another application that has the same size hub register as the A body Mopar. These slots I have are dedicated FOR the small bolt pattern A body Mopar with the smaller hub register. They are not unilug, so they are very specific.
 
For decades, "uni-lug" wheels centered the 5 lugs.....in slots.

...and it worked.

saved-by-the-bell-wow.gif
 
RustyRatRod said:
....and to be clear, I'm not knockin hub centric wheels like aluminum slots. I have a set I'm going to run on Vixen. As long as the center correctly on the hub, they can have a little play in the direction or the rotating wheel either way and they're still fine. It's the lateral play in relation to the hub they cannot have. In other words, hub centric wheels are usually very application specific, because in this case I don't know if there's another application that has the same size hub register as the A body Mopar. These slots I have are dedicated FOR the small bolt pattern A body Mopar with the smaller hub register. They are not unilug, so they are very specific.
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What you describe sound like they are hubcentric. They were probably made in a time when wheels were made by application to fit and are likely higher quality than you can get today.

Rings were brought in so a wheel could fit the same offset and bolt pattern among brands that would have different hub sizes. That said, I've had mine lost by the tire store jockeys and didn't notice the difference until I did a brake job and noticed they were missing.
 
dano said:
What you describe sound like they are hubcentric. They were probably made in a time when wheels were made by application to fit and are likely higher quality than you can get today.

Rings were brought in so a wheel could fit the same offset and bolt pattern among brands that would have different hub sizes. That said, I've had mine lost by the tire store jockeys and didn't notice the difference until I did a brake job and noticed they were missing.
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Yes, that's correct. They are hub centric.
 
dano said:
Didn't they have a hard steel oval washer to set the lug pattern?
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Some did and some had the actual holes in the wheels that were oval.
 
You can actually install uni-lug wheels without any washer.

I'd not advise tightening them down though, as the nut will dig in to the finish.

However, it allows you to see how the physics works.

By the time the third nut is on, it's centered.

They can only go on one way- centered.

The washer was mainly cosmetic, to cover the remainder of the exposed slot.

Because the washer was elongated, it tended to bend.

I ran my uni-lug Cragars with regular round washers.

MUCH stronger.

Brilliant design, really. Although I totally get why they can impart an uneasy feeling.
 
Here are the photos of the hub centric rings I just had custom made.

20220706_175147.jpg
20220706_175224.jpg
20220706_175306.jpg
 
Lol, what could possibly go wrong with a pair of Cragar SS that used these Vari-fit adapters from the '70s?
Pictures off the net......
upload_2022-7-6_19-38-43.jpeg
upload_2022-7-6_19-39-35.png
 
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