Wheel Spacers vs. Backspacing

[michaelgroves]

Wheel Centric; Right or wrong I always thought that it had more to do with concentricity than load carrying. So long as all of the bits involved are designed to use conic wheel nuts I never saw any need for it. I still don't.

Yes, that's my understanding too. Studs have been fine for load carrying on any size vehicle for the past 100 years, I can't see that changing. I think the move to hub-centric is to allow more precise centring of the wheel, and therefore better balance etc. (Also makes wheels easier to fit, I suppose, especially if wheel-bolts are used rather than studs and nuts.)

I could well be wrong on that point, though.

 

[R_Lefebvre]

Wheel Centric; Right or wrong I always thought that it had more to do with concentricity than load carrying. So long as all of the bits involved are designed to use conic wheel nuts I never saw any need for it. I still don't.

I'm pretty sure that on modern cars, the hub centricity is not just for wheel mounting and centering, but is absolutely necessary for load bearing. Could be what has allowed cars to go to smaller studs, from 5 to 4 studs, etc... The studs on the Disco are quite a bit larger than on any cars I've seen. Which is to be expected because the truck is bigger, but the difference is more than just that. With a bolt, if you double the size, you get 3-4 times the strength.

It's been a while since I went over this in depth. I have 2 friends working for an OEM in suspension engineering, I could ask if anybody really cares.

Maybe I should have said 6061-T6 "was" used on aircraft, which is how it got it's name. Talking maybe 50 years ago.

 

[TeriAnn]

I'm pretty sure that on modern cars, the hub centricity is not just for wheel mounting and centering, but is absolutely necessary for load bearing.

Since there are a number of Land Rover folks in this discussion I thought I might mention that Land Rovers (Series, Defenders, Disco I & earlier Range Rovers. I don't know about the newer vehicles) have mounting stud centric hubs & wheels.

One problem I have is whenever I get my Discovery I steel wheels balanced, if the guy uses a hub fastener on the wheel he tells my my wheels are out of round. I try to remember to tell them to mount the wheels on studs for balancing.

 

[R_Lefebvre]

Very interesting point. I never even thought of that one. Most wheel balancing machines these days mount on the bore of the wheel, yet that may not be the best surface to use, particularly on steel wheels.

Do they even have tools to mount the wheels on the balancer by studs anymore? I've never seen one.

 

[hoser]

Adapter to balance wheels by the studs.

http://www.haweka-usa.com/

 

[michaelgroves]

Very interesting point. I never even thought of that one. Most wheel balancing machines these days mount on the bore of the wheel, yet that may not be the best surface to use, particularly on steel wheels.

I'm curious - why particularly on steel wheels?

 

[98dango]

oops

 

[98dango]

well im a bit late on this but.

I will never agine run wheel spacers. In 2 diffrent ocasions i have had them loosen up. I also had a spacer break in half while crawling. I will not run them nor recomend them.

How ever my best friend runs 2" spacers on his toyota for over 150k with no problems. He also spent over 300 bux for 2 spacers and checks them once a week.

as far as berrings we get to gether every 6 months and service our rigs. Big part of 80/90 atf berring packing and drinking. We get about the same amount of life from out berrings.

 

[R_Lefebvre]

I'm curious - why particularly on steel wheels?

Well, because steel wheels tend to be of lower cost manufacture, and if the wheel was not designed to be hubcentric, it's entirely possible they did not spend as much attention on the exact location of the center hole relative the bolt circle. With an aluminum wheel, the bore would likely be machined. Steel wheels, it's punched, and may not be accurate.

What's the deal with wheel spacer nuts loosening anyway? Is it particular to wheel spacers? I've certainly never had lugnuts loosen.

 

[michaelgroves]

What's the deal with wheel spacer nuts loosening anyway? Is it particular to wheel spacers? I've certainly never had lugnuts loosen.

Don't know - I can't think of any reason a spacer would be more likely to come loose than the wheel. I'd use thread locker in any case, but just because people say that spacers come loose.

 

[R_Lefebvre]

That's exactly what I was thinking. And this whole discussion got me wondering if *I* should get some spacers. Since I'm running pizza cutters, the truck looks pretty knobby kneed. It might look a little better if they were pushed out a bit, plus give me the extra stability I'm missing from now having wider tires on. It's just something I've not really considered before.

I have facility to just machine my own out of steel. Anybody have any idea what grade would be best? 1040 good enough, or probably better to go with 4130?

 

[ntsqd]

Two thoughts on why spacer nuts 'loosen' in use:
1) Most spacers are made from aluminum. Anyone who has run aftermarket aluminum wheels has probably experienced needing to re-torque the lug nuts at least once. The wheels Brinnell in the conic lug nut seats, which is why the better aftermarket & some stock aluminum wheels have steel conic inserts. Eventually they'll stop, but until then the "nuts come loose."
We lost a desert race, five wheel studs, put our co-dog in serious jeopardy of getting hit, caused me to go on a "Mission from God" 50 mile drive for more studs, and severely damaged a competitor's car (from his hitting us in the dust) because the pit crew who was supposed to re-torque the lug nuts didn't do it.

2) Cantilevered loading. Increases the Brinnelling effect, and can probably stretch the wheel studs. Simply using a lug nut to pull in new wheel studs can stretch them and is a generally frowned upon installation technique. I don't see a spacer being too much different in the way that it can load a stud.

If you're going to make spacers I'd use a HSLA steel like 1144 or 1045 over a high alloy (with a fatigue life) like 4130. And some FEA on the design!