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Hub Centric Rings

qtrracer

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I believe "hub centric" isn't a centering device, but rather a load carrying device. By having the wheel hub-centered correctly, the load rides on the hub rather than on the studs. The studs/lug nuts are fasteners and when correctly used hold the wheel to the hub.

I've used plastic and aluminum hub rings and haven't had any trouble with either with one exception. After multiple wheel swaps with plastic rings, the little plastic clips tend to break-off and/or the centric part becomes enlarged defeating the purpose of the rings. Never had them melt despite may O/T events. The aluminum rings I've used are interference fit and don't use clips. Tend to last much longer with multiple wheel swaps. But, the aluminum ones are more pricy and not as easy to find in particular sizes.
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sigintel

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I believe "hub centric" isn't a centering device, but rather a load carrying device. By having the wheel hub-centered correctly, the load rides on the hub rather than on the studs. The studs/lug nuts are fasteners and when correctly used hold the wheel to the hub.

I've used plastic and aluminum hub rings and haven't had any trouble with either with one exception. After multiple wheel swaps with plastic rings, the little plastic clips tend to break-off and/or the centric part becomes enlarged defeating the purpose of the rings. Never had them melt despite may O/T events. The aluminum rings I've used are interference fit and don't use clips. Tend to last much longer with multiple wheel swaps. But, the aluminum ones are more pricy and not as easy to find in particular sizes.
Vertical load is transfered to rotor hat and hub by clamping force * coefficient of friction. Studs should always be under pure tension.
Failure mode design is to have wheel make hella freakn noise and vibration alerting driver to stop if clamping force insufficient.
All interfaces between wheel,rotor,hub,thrudrilled spacers, studs, lugs, etc should be clean and dry for assembly.
Use of grease based antiseize on spacers or adapters is disasterous obviously.
Hub center, centering rings, etc are for alignment and positioning of unloaded assembly during mounting.
Hub center provides failure mode load support only and hub should be discarded and replaced if hub center is loaded during driving due to clamp force insufficient.
-Engineer who reproduced on vehicle failure of tire and wheel systems for legal support.
 

qtrracer

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I think there is a bit of overstatement here. Hubcentric means that the wheel is centered on the hub rather than with the lugs (lug centric). The clamping force is transferred to the hub riding on the axle. But the fitment of the wheel over the axle hub center so there is a tight fit with no gap supports the weight of the car when hitting bumps or pot holes. The studs are only designed to resist lateral loads such as occurs in cornering. Without the weight being carried on the hub/axle, then the studs must support the car's weight during bumps which puts them into bending load. The joint cannot flex at all. If it does, the studs will bend and/or fail.

One wouldn't think that those little rings would do so much, but they do. Recommend running the rings and if plastic, checking that they haven't deteriorated from use.
 
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Norm Peterson

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I believe "hub centric" isn't a centering device, but rather a load carrying device. By having the wheel hub-centered correctly, the load rides on the hub rather than on the studs. The studs/lug nuts are fasteners and when correctly used hold the wheel to the hub.
I wouldn't count on plastic rings for carrying much load, certainly not long-term or under conditions involving higher than normal temperatures. But they are good enough to get the wheel centered while you're installing and torquing the lug nuts.

I suspect that wide wheels and wheels with considerable offset - as measured to the conical seats for the lug nuts rather than to the back side mating surface - are more needy of better initial centering than you can do "by hand".

Unless the hub-centricness borders on being an interference fit on both the wheel and on the hub, it's not going to carry any load under normal circumstances. As long as the lug nuts remain sufficiently tight, that's the job of clamp load and friction first, and lug nut conical shape with wheel stud stiffness probably ranks second (absent friction, they might deflect 0.0001" or so under a sustained vertical load).


One of the plastic rings I need to use with my track wheels cracked upon removing it from the hub side (picture a piston ring here). It still performs its locating-for-wheel-installation function just fine, and I don't even bother trying to super-glue the butt ends together any more.


Norm
 

ctandc72

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Hub rings are commonly made of plastic. I've run them on multiple vehicles, many of them run HARD - never had any issues.

I can tell you that it depends on the car / wheel setup. I've seen cars with a slight vibration at speed. They did road force balancing, checked for warped wheels, etc etc. Installed hub rings (wheels were high end aftermarket wheels) and the vibration went away.

As for tightening lugs / wheels....I've been doing my own maintenance for 30 years. I've never had an issue tightening one lug (usually the bottom lug) by hand (either fingers or socket by hand) while holding the wheel flush against the hub. Install / hand tight the other lugs, tighten with breaker bar / ratchet until wheel wants to spin. Drop car down until tires touches ground and suspension starts to compress / load - then torque wheels to spec.

Did the same routine on numerous dirt track and other race cars with never an issue.
 

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Grintch

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Hub rings are commonly made of plastic. I've run them on multiple vehicles, many of them run HARD - never had any issues.
I lost a wheel using plastic centering rings when experimenting with fitting larger slicks on the SRF. Part of the problem was they melted.

The plastic centering rings I got with my Forgestars on the Mustang melted at their first track day. I scraped them off, threw then away, and said no more plastic for me.
 

DickR

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I have about 25,000 street miles plus hundreds of autocross runs using PP size Forgestars on my 15 Mustang without centering rings. I carefully allow the lug nuts to center the wheels properly while progressively tightening/torquing the nuts.
 

sigintel

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I think there is a bit of overstatement here. Hubcentric means that the wheel is centered on the hub rather than with the lugs (lug centric). The clamping force is transferred to the hub riding on the axle. But the fitment of the wheel over the axle hub center so there is a tight fit with no gap supports the weight of the car when hitting bumps or pot holes. The studs are only designed to resist lateral loads such as occurs in cornering. Without the weight being carried on the hub/axle, then the studs must support the car's weight during bumps which puts them into bending load. The joint cannot flex at all. If it does, the studs will bend and/or fail.

One wouldn't think that those little rings would do so much, but they do. Recommend running the rings and if plastic, checking that they haven't deteriorated from use.
My apologies for my epic fail previous explanation.

Wheel and hub do not move in relation to each other.
Studs and lugs on correctly assembled and torqued wheel are in pure tension even if you hit a pothole and break the rim.

Hit a bump, ... or pot hole, ...or curb going 120, ...or brick wall.
You will rip the suspension off the car before the wheel transfers load via the hub center instead of the wheel/hub surface compressed (clamped) by over 100,000 lbs of compressive force (5studs x 20,000#).
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