The Stovebolt Site Forums The Shop Area Driveline Stud VS hub piloted wheels

Quite often, part of the "resto-mods" we do on our trucks includes swapping wheels. On 1/2 through 1-ton trucks, most of them originally have tapered lug nuts that center the wheel bolt holes on the lug studs, but most of them also have a close-fitting center hole that mates with a flange on the front hub or rear axle. Sometimes an aftermarket wheel will have a bigger center hole, so all the stress of holding up the vehicle is carried by the lug studs. How about some comments on how the group feels about matching up the wheel center hole size with the hubs/axles? Critical, "nice to do", "makes no difference", etc. I've always been just a little uncomfortable about trusting the studs to carry vehicle weight as well as hold the wheels on.
Jerry

As long as the bolt holes are tapered and you use tapered lug nuts, my opinion is that it makes absolutely no difference how big the center hole is.

My F250 has "hub-centric" wheels and flat lug nuts with captive washer. The real purpose of the close fitting center hole in that instance is to center the wheel on the hub. With "lug-centric" wheels, the tapered lugs do the centering. In both cases, the clamping force of the lugs is what holds the wheel on, and hold the vehicle up, although with "hub-centric" wheels, if you run around with loose lug nuts you might go a few miles farther before the wheel falls off.

I have no technical data either way as to which is better. Logic says the bigger the load the more stress applied to the wheel/hub mounting point.

To me it makes sense for larger vehicles to have a tight hub fit as to support the load better. The OEM companies have a way bigger R&D budget than any of us, they probably set things up in the cheapest and most effective way they found.

That being said I would say the importance of matching hub size would depend upon loads carried. 1/2T used as a daily driver rarely loaded....eh who cares, 1T+ working everyday should probably get darn close.

My opinion for what it's worth.

So long as you’re following what was originally intended, wheels with tapered lug nut seats get tapered lug nuts, or otherwise for other wheel mounting systems I wouldn’t worry.
The system was figured out when the vehicle was new and if you have problems with wheels falling off you either have it implemented wrong or severely overloaded.

The heavy truck world has moved to hub centered wheels by and large, but many cars and some trucks still use stud centered wheels. I view them as both OK and wouldn’t bother trying to make one system into the other for no good reason.

“Budd” wheels, stud centered, for heavy trucks have been around for well more than half a century (a whole one yet?) and still in use. Mike’s fire truck has them. The studs are quite large, obviously designed for the job at hand.

I have seen issues with aftermarket aluminum rims on hotrods coming loose due to the combination of not being supported by the hub, and likely from expansion and contraction of aluminum from heating/cooling cycles, and improper torque specs.

I'm in the process of converting my daily driver (1,000+ miles a week) To a slightly lower profile tire/wheel setup. The wheels I'm using have a center hole about 3/4" bigger than the OEM wheels. Both wheels use the same lug spacing and tapered lug nuts. I'm in the process of machining a ring to press-fit over the rear axle flange to allow the wheel to center on the hub, as well as the lug studs. It's sort of a "belt and suspenders" approach to holding up a pair of pants, but it can't hurt. The tire size change is from 245/70-17 tires to 235/70-16's. There's a bit over an inch of height difference, which translates to 3"-4" difference in circumference.

The whole reason for the lower-profile tire is to try to change the road speed where the torque converter clutch unlocks- - - -right now the comfortable cruise speed is 75MPH and 2000 RPM. That's close to speeding ticket territory, even on the interstate, and the vehicle doesn't like 55 MPH 2-lane roads at all. A side effect beyond playing Smokey and the Bandit all the time just might be batter gas mileage. Right now I'm pretty sure I'm lugging the engine down at times and going into full-fuel power mode way too often.
Jerry

Just about every owner's manual says recheck wheel lug nut torque after 50 miles, but has anyone actually done that?

Jerry, no problem with your belt and suspenders approach with the rings, but I don't think it's really necessary.

A tapered nut, in a tapered hole, forces an "exact fit". Tolerances would never allow 6 or 8 tapers to all seat. Therefore not all are perfectly seated even if a tightening pattern is followed. There will be a few nuts that center the wheel to the centerline of rotation of axle. That will have it's own tolerances. There will be a few nuts partly in the taper and mostly just clamp........... but the system is suffice.

It is impossible to have the load carried by tapered nuts AND a tight fit hub. Tolerances will not allow that. The wheel center hole has to have clearance to the hub to allow the wheel to move/seek the taper of the nuts....or the studs have to have clearance in the wheel holes to allow a tight hub fit.

As you know, it has been said, that hub centered is better for load strength but it may allow wheel to turn and apply a shear load to untapered studs........... but the system is suffice.

You can play around all you want, you can't beat the tolerance Gods.
Agree with Grigg.
I also say, you are fixing a problem that does not exist. Either system is strong. The number of studs and the size has been designed/engineered to probably a 2.5X safety factor. Not to worry. What is this daily driver?

It ain't a stovebolt, so I ain't saying. The PC Patrol gets too many opportunities to rap my knuckles already! The centering ring will help during a tire change, if nothing else. I'm also discarding a set of aftermarket alloy wheels in favor of OEM-style steel wheels. Those who don't agree with my approach- - - -please note the sprig of mistletoe attached to my untucked shirt tail!
Jerry

No warning of mistletoe?

Come on Jerry, is it a Ford? A Mopar? Jap? Tell us, the mistletoe will cover your xxx.

04 Dodge RAM 1500- - - -200K miles on the chassis- - - -100K on the engine.
Jerry

That's it, you are banned until it's sold. 200K on chassis and 100K on motor? That's a lot of coasting ain't it?

Hope nobody finds out I have a 2011 F150 4X4, a 1957 Willys 4X4 Truck, a 2001 Trailblazer and 1960 GMC 4X4.

"Georgia Overdrive!"

Why is this thread in the Driveline Forum?! How are we supposed to keep the archive in a searchable form with such a blatant violation of policy, why, anyone with 2-3 brain calls to rub together should know what kind of chaos this misplacement of topic would cause...

Carl
trying to earn avatar status without doing actual work

Fork lift: wheels squeaks sliding on center hub and ten flat flare nuts---no problems
Ranger: aluminum with oversize center hole and tapered lug nuts---400k miles no problems
Sprint and Super Modified circle track cars: six drive pins (no threads) and knock off center nut---no problems
Many of the old knock offs had a plate to even out the stress so Jerry's idea has merit.
How would I vote---no idea

Update- - - -16" wheels drag on the brake calipers- - - - -got some 1/2" thick spacers on order. With the 14MM wheel studs and plenty of length, the lug nuts will still have lots of thread engagement. The centering rings make a little more sense now, to me, at least!
Jerry

I guess you're right on the centering rings, but spacers are never a good idea, IMO.

These are simple 1/2" thick flat rings that the OEM lug bolts go through, not the bolt-on ones with their own studs- - - -I wouldn't use that kind of thing on a lawn mower! The wheels just need a bit more clearance to keep from rubbing the calipers. I might even be able to machine them down to 3/8" thick once I check on the clearance.
Jerry

OK It's your truck. I definitely agree on the bolt-on adapter spacers - those are an accident waiting to happen. If you do thin the spacers, you could turn them into your centering rings by leaving a bit more thickness to match your wheel centers.

50-something years of building dirt track race cars makes me tend to over-build everything. There's nothing on the street that can compare to a few laps around a 1/4 mile dirt oval.
Jerry

Can't argue with that.