Hub centered rims and NON-hub centered rims

[TRAMPLINEMAN]

Motörhead,

I'm about 99% sure that the motorsport-tech link you posted is where I got them from.

 

[TRAMPLINEMAN]

Seafish,

I agree the rings are not needed. But, they did make installing easier and they were not expensive.

 

[Motorhead]

Seafish, You may get away with using the lug centric wheels - the whole engineering point of the hub centric wheel and the tight tolerance is that the weight of the load transfers from the wheel to the hub, not the lug nuts / studs. The lug function is the hold the wheel onto the hub assembly, not carry the weight per se.

You can find examples where folks use lug centric wheels on HD trucks, however the hub diameter of Dodge and Chevy is 6.5" or 165.1 mm. Ford switched in 99 to a 170mm hub, that is why the older Ford, Chevy Dodge 8 lug wheels will not fit a Super Duty, hub is too small.

Good luck with your decision, but I will keep the hub centric wheels. I currently have 285-70-17 Nitto Terra Grapplers on stock Dodge Aluminum wheels. I tow heavy at times, 13K+ with a gooseneck trailer loaded with hay. The entire suspension system needs to be able to handle the stresses involved. Static pin weight with the 13K load is ~ 2900 lbs. Add the stresses of driving, with the bumps and suspension movement naturally encountered and the instantaneous loads are a peak function of a sinusoidal mathematical function, or simply put 2900 x 1.4 = 4060 lbs pin weight add this to the nominal rear axle weight of 3200 x 1.4 = 4480 + 4060 = 8560 which divided by 2 for each wheel is 4270 lbs in a worse case situation for instantaneous loading.

Point is there is engineering margins built into the entire suspension system [25 to 35%] to handle worse case loading factors - with lug centric wheels, the lugs where not designed to handle this weight and could result in damage or an accident if heavily loaded.



Good Luck --

Luke

ACTUALLY.... the hubs on MY Dodge and YOUR 2006 is 121.3mm with a 123mm wheel center I.D. STOCK. 1mm = .0394". The CLEARANCE then between the O.D.of the hub and the I.D. of the wheel is .0334" because you take the total clearance of .06698" and divide it by 2 to get .0334". So the I.D. of the wheel is not riding on the hub. If you are saying the lug studs can flex 34 thousandths, no wait a second, they might have to be able to flex almost 67 thousandths repeatedly on a STOCK wheel just so the inner part of the wheel can hit or rest against the HUB..... Hmmm... Better have your facts straight. The STOCK wheels you are over loading are CAST wheels. Explain to us why Rickson HEAVY DUTY wheels ARE NOT HUB CENTRIC and yet they are rated to a higher per wheel load that your stock, CAST wheels. That's my $0.02 worth!

 

[cerberusiam]

I agree the rings are not needed. But, they did make installing easier and they were not expensive.

Yes, they make installing and aligning them a lot easier but not needed, no way. On a light car it is probably not an issue but on a truck that is carrying 3 times the weigth of these cars on 8 small studs is just asking for problems.

The 2 posted articles are radically diferent in what they are talking about and the author of the first has evidently has not ever gotten beyond owning a feather weigth vehicle. Loading lug-centric wheels on anything less thean the 1" studs of the MD trucks is just crazy. The 1/2 and 9/16 studs will NOT last if axle weights are near or above max.

One can get by if one is dligent about checking TQ frequently but it is still just a problem in the making. Once one has broken the studs and had to deal with the results it drives home the potential for disaster. Run them if you like but it is no different than runnign 6 ply tires in an application that requires 10 plys, it is only a matter of time.

 

[seafish]

Seafish, You may get away with using the lug centric wheels - the whole engineering point of the hub centric wheel and the tight tolerance is that the weight of the load transfers from the wheel to the hub, not the lug nuts / studs. The lug function is the hold the wheel onto the hub assembly, not carry the weight per se.

You can find examples where folks use lug centric wheels on HD trucks, however the hub diameter of Dodge and Chevy is 6.5" or 165.1 mm. Ford switched in 99 to a 170mm hub, that is why the older Ford, Chevy Dodge 8 lug wheels will not fit a Super Duty, hub is too small.

Good luck with your decision, but I will keep the hub centric wheels. I currently have 285-70-17 Nitto Terra Grapplers on stock Dodge Aluminum wheels. I tow heavy at times, 13K+ with a gooseneck trailer loaded with hay. The entire suspension system needs to be able to handle the stresses involved. Static pin weight with the 13K load is ~ 2900 lbs. Add the stresses of driving, with the bumps and suspension movement naturally encountered and the instantaneous loads are a peak function of a sinusoidal mathematical function, or simply put 2900 x 1.4 = 4060 lbs pin weight add this to the nominal rear axle weight of 3200 x 1.4 = 4480 + 4060 = 8560 which divided by 2 for each wheel is 4270 lbs in a worse case situation for instantaneous loading.

Point is there is engineering margins built into the entire suspension system [25 to 35%] to handle worse case loading factors - with lug centric wheels, the lugs where not designed to handle this weight and could result in damage or an accident if heavily loaded.



Good Luck --

Luke

LFalconer,my understanding is that it is PRIMARILY the "clamping load" of the lug nuts that distributes wheel load to the axle. I would even go so far as to suggest that on a PROPERLY installed and PROPERLY torqued wheel installation, the clamping load replaces or even negates any shear load directly placed on the lug nut. If that is the case, while obviously there is nothing to be lost and something to be gained (priamrily ease of install) by always running hubcentric wheels, I do not believe that having a lugcentric wheel negatively effects load capacity, and here is the caveat...AS LONG AS the wheel is in a true AND well balanced condition and it is CORRECTLY installed and torqued.

That being said, since "real world" conditons DO effect wheel trueness (think potholes) AND correct install (think tire jockey or grease monkey), then hubcentric wheels ARE likely safer in real world conditions, but I do not think that they in any way add to load carrying capacity or taht properly installed lugcentric wheels neagitvely effect built-in safety margins. In short, easier to install correctly, thus inherently safer, YES...(in fact if I could find a reasonably priced hubcentric ring to use on my truck, I would do so), but ACTUALLY stronger then a properly sized and installed lugcentric wheel in true condition, NO.

 

[Motorhead]

Yes, they make installing and aligning them a lot easier but not needed, no way. On a light car it is probably not an issue but on a truck that is carrying 3 times the weigth of these cars on 8 small studs is just asking for problems.

The 2 posted articles are radically diferent in what they are talking about and the author of the first has evidently has not ever gotten beyond owning a feather weigth vehicle. Loading lug-centric wheels on anything less thean the 1" studs of the MD trucks is just crazy. The 1/2 and 9/16 studs will NOT last if axle weights are near or above max.

One can get by if one is dligent about checking TQ frequently but it is still just a problem in the making. Once one has broken the studs and had to deal with the results it drives home the potential for disaster. Run them if you like but it is no different than runnign 6 ply tires in an application that requires 10 plies, it is only a matter of time.

So WHY would TWO companies, like Rickson and Centerline forged wheel, build their wheels NOT hub centric and risk the liabilities that their products might cause a LUG bolt shearing
failuer under over load issues? I am not trying to argue this with everyone...I'm JUST trying to understand if I really need these rings added or not.

 

[seafish]

Motorhead, thanks for the link, but I could not find the link for actual custom sizes...also it looks like the larger ones they have are over $50 each, even in plastic...let us know what you find if you call them. I would suggest that while you do not need them, you might want them.

 

[seafish]

Cerberusiam, I realize that each article presents an opposing point of view, that is why I posted BOTH of them. While I am not an engineer, here is yet another link with several engineers chiming in--

http://www.garagejournal.com/forum/showthread.php?t=48161

The important part to understand, at least for me, is that engnineered CLAMPING FORCE is PRIMARILY what transfers load from the wheel to the axles....hubcentric and lugcentric refers (as the name implies) to wheel CENTERING strategies, NOT axle loading strategies...lug nuts operate in shear loading ONLY when improperly installed, and then they are doomed to fail no matter what.

 

[Motorhead]

Motorhead, thanks for the link, but I could not find the link for actual custom sizes...also it looks like the larger ones they have are over $50 each, even in plastic...let us know what you find if you call them. I would suggest that while you do not need them, you might want them.

seafish. Go to the link and open it to the hubcentric ring section. http://www.motorsport-tech.com/4DCGI/errors/h_err_ymm.html Input your truck year and model. It says Select center bore of new wheel. It says down below, If your vehicle's center bore is NOT in the list please enter it here (in millimeters). I put my NEW wheel I.D. of 130.81 and then they have you put the quantity (4) and it gives me a price of $25.00 each. I think that if a very fair price as they probably have to make them up.

THANKS for your input on this with backup statements found on the web.

 

[NIsaacs]

Loading lug-centric wheels on anything less thean the 1" studs of the MD trucks is just crazy. The 1/2 and 9/16 studs will NOT last if axle weights are near or above max.

Lug centric wheels have been around almost since the invention of the wheel. They are still being used today in numerous applications, they work. 7k trailer axles use them, thats 3500 lbs per corner. The only lug centric wheels that I have had any problem with were the old style double sided coined dually wheel on a tandem axle trailer. They never were any good, Ford, Dodge and IHC used them in their 1ton sized cab chassies, Chevy used the hub centric on their duallies, they worked great. They both work and both have their place.

Nick

 

[Motorhead]

Thanks Nick... Chris

 

[cerberusiam]

The important part to understand, at least for me, is that engnineered CLAMPING FORCE is PRIMARILY what transfers load from the wheel to the axles....hubcentric and lugcentric refers (as the name implies) to wheel CENTERING strategies, NOT axle loading strategies...

Yes and No. Even in that article only one person got it right while the others were to busy playing with math to see the difference. :-laf

The one person that got it right said it quite clearly "you cannot separate the force load from studs to hub, the hub-centric (pilot hubs) carry part of the load". The physics of the application demands that be true. The lateral and torsional loads are not the problem, its the shock load of the ground contact point applied to only one lug that causes failures in the stud-centric systems. The aluminum alloy wheels are worse than steel because they are stiffer and transmit more load when it happens. Without the hub to take part of that load it exceeds the shear on the stud. Where that break point is becomes totally dependent on load, surface conditions, and somewhat speed.

Hub-centric and lug-centric is never about centering the wheel as far as the design goes, it always about where the load is carried. The divergence comes about when talking about adding non-OE wheels that are a generic design that fits more than one application. That is the difference of the context of the first 2 articles, load versus balancing. In a car application it almost always going to be about centering the wheel. That is all that is really needed.

The other important thing to note is the wheel rating really has nothing to do with loadable rating when it comes to the wheel\axle connection. If the rating of the clamping force based on hub face area, stud size, and TQ is 3500 lbs and the wheel is rated for 4000 lbs, the load rating in that application is still only 3500 lbs. The amount of surface area of the wheel on the hub will effect that rating also.

Trying to compare wheel ratings to OE wheels gets to be a big guessing game becasue a lot of OE wheels do not have stamped rating. Their rating is assumed to be 1/2 the axle rating because of the engineering design. That will NOT hold true for non-OE wheels.

The reality is that in most cases the lug-centric wheels used with the recommended lug nuts on an 8 hole wheel is adequate for the rated loads of the vehicle. Even if you never exceeded the load rating and had problems, how could you ever prove that? Operator error is by far going to be the root cause because it is almost impossible to prove otherwise so of course there are no big issues heard about this in forums.

Again it comes back to operator choice to run what they want. Trying to categorically prove a certain wheel design is going to fail in a certain situation is very hard and very expensive to do.

 

[Motorhead]

quote from cerberusiam..."Hub-centric and lug-centric is never about centering the wheel as far as the design goes, it always about where the load is carried."
SAY WHAT???? You are aying that a taper fit lug or a hub in spec with a wheel is NOT about centering a wheel?? I am sorry but that is dead wrong!

 

[cerberusiam]

quote from cerberusiam..."Hub-centric and lug-centric is never about centering the wheel as far as the design goes, it always about where the load is carried."
SAY WHAT???? You are aying that a taper fit lug or a hub in spec with a wheel is NOT about centering a wheel?? I am sorry but that is dead wrong!

See what I mean about context? If the verbage doesn't convey the context correctly things go sideways. Try this: "Hub-centric versus lug-centric is never about centering the wheel as far as the design goes". Just did not think about the portrayal of the concept long enough.

Centering (fitment) is NOT a design criteria, it is the RESULT of the design. Trying to determine the load capability and suitability based on fitment is going about it backwards.

Tapered lug nuts are not neccessarily an indication of lug-centric design or centering either, it is also a way to provide more area for the TQ to work on. The stock alloy wheels have taper lug nuts and a hub-centric design. Suppose the engineering thoughts behind that had anything to do with load carrying capability?

 

[seafish]

See what I mean about context?
Centering (fitment) is NOT a design criteria, it is the RESULT of the design. Trying to determine the load capability and suitability based on fitment is going about it backwards.

Cerbusiam, I realize that you know ALOT about how these trucks work, and I would not even disagree with much of what you are saying here becuase I know that you mean to keep people as knowledgable and safe as possible with their trucks running reliably!!! However, I have to respsectfully disagree with this statement IN CONTEXT because I am sure that fitment IS an actual design criteria and NOT simply the RESULT of wheel design... simply because it is obvious that fitment and load carrying capacity DO go hand in hand or else anybody could run whatever wheels they wanted that would bolt on andthen get into a lot of trouble really quickly!! Furthermore, I think that one of the reasons that manufacturers moved to hubcentric designs is the it is easier to insure proper wheel fitment with less care and knowledge, thus fitment is once again a design criteria.

While I can recognize that many, though NOT all, aftermarket wheel manufacturers strongly suggest using a hubcentric ring with their product, I am also convinced that this is for installation LIABILITY issues and not necessarily load engineering issues. There is NO queasiton in my mind that hubcenteric wheels are easier to install safely then lugcentric ones. However, Rickson has chosen to offer their wheels without the need for hubcentric rings and I am positive that we would be reading about plenty of Rickson lawsuits if their wheels were failing, which they would be because they are offered as a heavier duty upgrade to oem wheels so that poeple can tow MORE safely with their trucks (up to axle load capacity obviously), not the same or less.

All in all, I am pretty sure that we are agreeing about most everything EXCEPT the role of clamping force versus shear strength in determining wheel safety and design...I am pretty dam sure that clamping force exists the same in both hubcentric and lugcentric wheels of the same load rating and also I am pretty sure that it IS the clamping force that resists both shear AND impact breakage. Of course, I am NOT saying that lugcentric wheels are safer then hubcentric ones, only that properly designed, manufactured and installed lugcentric wheels are as safe with in their load limits as hubcentric wheels are within theirs.

 

[cerberusiam]

Yep, aside from what amounts to some philosophical differences we agree. While I don't *think* there is a problem running the lug centric wheels at rated loads in most suituations, I still have concerns based on general experience that a lug centric wheel is not the best solution for a heavily loaded axle. I cannot convince myself a 4.5" backspace wheel is a good idea on these trucks either.

Both are frequently done and the world has not ended so the odds are in favor. :-laf

 

[JJPage]

I cannot convince myself a 4.5" backspace wheel is a good idea on these trucks either.

You are right about this, not only does it place undue stress on all components involved, it allows road debris to be slung all over the side of your truck, and any other vehicle in the immediate vicinity, and...it's ugly! Jess

 

[d6c]

The listed hub diameters are actually the bolt circle diameters.....which is the reason they do not interchange. Not withstanding the center hole possible difference. BTW add me to the list of aftermarket wheels guys without spacer rings not having any problems. Spacer rings are a token effort at best....now you have two gaps and just how tight can you make things fit. Now my f450 uses a real hub pilot system...lug nuts are washered and flat...no cones, and even without the lug nuts installed you have a hard time getting a wheel off the rig.

Seafish, You may get away with using the lug centric wheels - the whole engineering point of the hub centric wheel and the tight tolerance is that the weight of the load transfers from the wheel to the hub, not the lug nuts / studs. The lug function is the hold the wheel onto the hub assembly, not carry the weight per se.

You can find examples where folks use lug centric wheels on HD trucks, however the hub diameter of Dodge and Chevy is 6.5" or 165.1 mm. Ford switched in 99 to a 170mm hub, that is why the older Ford, Chevy Dodge 8 lug wheels will not fit a Super Duty, hub is too small.

Good luck with your decision, but I will keep the hub centric wheels. I currently have 285-70-17 Nitto Terra Grapplers on stock Dodge Aluminum wheels. I tow heavy at times, 13K+ with a gooseneck trailer loaded with hay. The entire suspension system needs to be able to handle the stresses involved. Static pin weight with the 13K load is ~ 2900 lbs. Add the stresses of driving, with the bumps and suspension movement naturally encountered and the instantaneous loads are a peak function of a sinusoidal mathematical function, or simply put 2900 x 1.4 = 4060 lbs pin weight add this to the nominal rear axle weight of 3200 x 1.4 = 4480 + 4060 = 8560 which divided by 2 for each wheel is 4270 lbs in a worse case situation for instantaneous loading.

Point is there is engineering margins built into the entire suspension system [25 to 35%] to handle worse case loading factors - with lug centric wheels, the lugs where not designed to handle this weight and could result in damage or an accident if heavily loaded.



Good Luck --

Luke

 

[LFalconer]

The listed hub diameters are actually the bolt circle diameters.....which is the reason they do not interchange. Not withstanding the center hole possible difference. BTW add me to the list of aftermarket wheels guys without spacer rings not having any problems. Spacer rings are a token effort at best....now you have two gaps and just how tight can you make things fit. Now my f450 uses a real hub pilot system...lug nuts are washered and flat...no cones, and even without the lug nuts installed you have a hard time getting a wheel off the rig.

Wow, Didn't mean to ignite a flame on the thread - what d6c said is true on 450 and 550's my son has a 550 and it is a true pilot system. I also own a gooseneck flatbed and a gooseneck cattle trailer rated for ~ 15K lbs, both have hub centric wheels - with a small tolerance to ensure you can mount them. All assemblies have to have some tolerance to allow for mfg variations and temperature variations. Again - I am not stating that you cannot run a lug centric wheel, just expressing my views on the use of the wheels in a loaded application with the real work overloads -- Good luck with your decisions - we each ultimately take responsibility for the modifications to our trucks in loaded situations - in Virginia if there is a failure or accident in a loaded conditions likely VDOT will review the situation, or lawyers if there is a chance of neglect...

Luke

 

[brods]

We all have to decide what to believe, but we should also factor in the risks of being wrong. Factory is hubcentric for a reason.

If you do go with aftermarket wheels remember to remove the rotor retaining clips off the studs (if they are still there). If you go lugcentric be aware that there is a preferred method for mounting the wheel to the truck, don’t just throw it up there and tighten all the lugs. Iirc it involves putting a nut snug at the top, rotating the wheel 180 degrees and repeat. Once all the nuts are snug they are to be tightened down in three steps.

Broken studs are relatively rare but do happen. Here a few examples:
https://www.turbodieselregister.com/forums/showthread.php?225040-Check-your-wheel-studs
https://www.turbodieselregister.com/forums/showthread.php?178023-help-broken-lugs
https://www.turbodieselregister.com/forums/showthread.php?207554-Broken-wheel-studs