It's almost that simple
...
I did a little poking around to see if there was a better explanation. I like to know why vs hearing "do this or you'll hit a busload of nuns" or "do it because the OEM does it."
The short answer is
buy whatever wheel you want, and if you're concerned about centricity, buy a hub centering ring even if they're "lug centric" wheels. And the extension to that is,
don't worry about centricity if you're buying a modern, quality wheel...which is pretty much everything on the wall at your favorite shop.
Sources were an older thread here with a couple posts by DJ and KLS, comments from an engineer at Enkei, the Pirate 4x4 knowledge database, and a local tire shop I know and trust (about a six year history, same guys).
First thing to understand is that
the lugs and nuts are not shear loaded. They simply clamp the wheel to the hub, so the bearings take the load. In other words, anybody saying you need hub centric to take the load off the studs doesn't know what they're talking about...particularly on our trucks, where the FWD-style hub has only a centering cone. The lugs were not designed to be loaded in shear. Heaven help you, if the weight of your truck is riding on that centering cone! You'll hit a busload of nuns for sure.
Next is that
any modern, quality wheel is finished on a lathe, with the center bore as the locating dimension...not the lug holes
, which are cut later. The tire shop uses a centering cone to attach that wheel to the balancing equipment (hopefully a Hunter machine with road force balancing
), vs the lug nuts which would take forever. Ever notice they don't mess with lug nuts on the balancer? That's why...a variety of centering cones means there's one to fit every wheel, and
whether your wheel requires studs with a tapered or flat clamping surface, it's being balanced hub-centric on the machine. In other words...your new rims are 99.9% guaranteed to be both hub centric (tho not necessarily to your hub) as well as lug centric. The tolerance allowed for screwing up the location of the tapered lug holes is a fraction of a millimeter (0.3mm, IIRC) or it's considered out of round and a defect. I suspect, if you were to measure (with a machinist's centering tool and other devices) the non-tapered holes on a stock Toyota alloy rim, you'd find it was within that tolerance, and that my wheels have the same tolerances but with a different center bore.
The exception seems to be wheels that are
only lug-centric...I didn't ask about 'em because all the quality wheels I can think of are either started or finished on a lathe (or both, for some welded steel rims). If you have rims which are
only lug-centric, they require a lug-centric adapter, and it is apparently a colossal PITA for everyone involved
. Get quality rims and you don't have to worry about this.
Interesting note, I have two sets of rims, both require a tapered nut. On the front, where I no longer have a centering ring, they are completely lug centric during installation. On the rear, they are hub centric to the Dana 60 bodies but still require a tapered nut. Also worthy of note, they're a helluva lot easier to deal with on the rear axle because they center on the hub
. Finally, I'm willing to bet that once installed, the front wheel and tire is concentric with respect to the vehicle hub...otherwise I'd certainly notice, with a tire this large!
So how do you take any random wheel requiring tapered nuts and make it hub-centric (ie make life easier for yourself and the tire shop)?
Ask the seller or manufacturer
about getting a centering ring for their rim
to your vehicle...it'll be just like the centering ring Toyota uses, only to fit the new rims.
Why?
Instant reduction of the PITA factor associated with lug centering. It is a huge pain in the *** to take a 115# wheel/tire combo and juggle it around while you get six deep-set nuts seated, and then there's all the playing around turning the tire to make sure nothing's being pulled around while the wheel is being seated against the hub. Of course, I'm really anal about it...the tire shop is just gonna blast it on, and their way works just as well, if a little sloppier and more likely to break a stud. If you have a centering ring, you slide the wheel on, and it sits there while you kick back with a brew and take your dear sweet time installing the nuts.
Where does that leave you, buying wheels?
Get whatever you want. If you want to make life easier for yourself, get a set of
polycarb centering rings. FWIW if you get aluminum, your hubs are steel and you'll have a helluva time getting that ring off once it's corroded to the hub. Don't worry about the plastic because all it does is center the wheel, not hold it up...friction does that, by way of the clamping force provided by lug and stud.
Always, always, always! put the wheel on the axle and
tighten the lug nuts while it's still in the air. If you drop it down loose with a lug-centric rim, it'll shift and you'll read 83ft# torque on the wrench, but it won't be properly fastened at each lug. You're also risking shearing a lug. If you drop it down loose on a hub-centric rim, you're likely to break off the centering cone. So always get it centered and tight in the air, and it'll work no matter what rim design or lug nut shoulder you're using.
That's about all I could find, hopefully it helps. I didn't bother to link any of the sources for centering rings, ask your tire shop...they oughtta be able to get them through the manufacturer if you want them.
Bottom line...your new, quality rims are hub centric. Whether you like it or not, whether you have the right centering cone/ring or not, they're hub centric
. If they have tapered seats for the lug nuts, you shouldn't need the centering ring. If they have flat seats, you must use the centering ring. Centering rings/cones are available all over the place.
...Come to think of it, my American Racing wheels came with centering cones even though I didn't request them, and the wheels have tapered seats. I stopped using the cones to seat the front wheels when I converted to manual hubs...so likely
both sets of wheels I have are both hub
and lug centric.
So have fun with your new rims and let your tire shop worry about centricity
.
Either lug nut style can work on your vehicle.
I also went back and edited the garbage out of my previous post and left a note regarding why my wheel/tire combo can be balanced so well.
-Sean
Do I buy Lug centric or Hub centric wheels??
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