Got these coming

Penguin VII · September 19, 2017

Since we have so many engineers here can someone point me to any information as to how the wheel spacers don't have an issue with sheer force? I googled a few times but didn't find anything that explained the science behind it.

silveradosid · September 19, 2017

being hub centric means that they fit tight on the hub and that is what carries the load the wheel nuts just hold it in place if any of the nuts that hold the spacer on come loose then you will have sheer force

Penguin VII · September 19, 2017

being hub centric means that they fit tight on the hub and that is what carries the load the wheel nuts just hold it in place if any of the nuts that hold the spacer on come loose then you will have sheer force

Ah! I only ever see these from the front side. So I'm guessing there is a lip that is machined that fits around the hub?

Additionally, would this cause issues with the suspension? You're pushing that "centerline" out further. I assume this is roughly the same as buying a rim with a high offset? (one that pushes the wheel further out from the centerline)

Sierra706 · September 19, 2017

Ah! I only ever see these from the front side. So I'm guessing there is a lip that is machined that fits around the hub?

Additionally, would this cause issues with the suspension? You're pushing that "centerline" out further. I assume this is roughly the same as buying a rim with a high offset? (one that pushes the wheel further out from the centerline)

It does put more stress on components. Our trucks are designed to tow and carry loads, so if your driving around using your truck as a commuter vehicle you most likely will never create any issues. However if you push your vehicle to the limits regularly , the spacers will accelerate any problems.

A friend of mine put large spacers and offset wheels on his Mazda CX-5. Within months his wheel bearings were totally shot.

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slickman · September 19, 2017

It does put more stress on components. Our trucks are designed to tow and carry loads, so if your driving around using your truck as a commuter vehicle you most likely will never create any issues. However if you push your vehicle to the limits regularly , the spacers will accelerate any problems.

A friend of mine put large spacers and offset wheels on his Mazda CX-5. Within months his wheel bearings were totally shot.

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Not a very good comparison, apples and oranges.

slickman · September 19, 2017

Lets remember, putting spacers or large offset wheels are the same thing. Spacers get a bad name because so many install them wrong or get crazy with the offset. There are many on this forum (too many to count) who use spacers the correct way and never have issues, work truck or not.

Penguin VII · September 19, 2017

Well some good information here and things to think about. I personally don't tow much except for a small trailer for jetskis or skidoos from time to time. Not a lot of weight. Need to figure out the correct spacers once I get the flares.

bgweed · September 20, 2017

Since we have so many engineers here can someone point me to any information as to how the wheel spacers don't have an issue with sheer force? I googled a few times but didn't find anything that explained the science behind it.

I hope the below may help to provide more detail and clarification to what others have already said.

Offset and Forces (the moment problem)

Generally, the stock wheel offset tries attempts to place the centerline of the wheel in vertically alignment with the centerline of the wheel bearing(s). This offset gives room for things like the brake disc hat.

For example, a +25 wheel offset puts the centerline of the wheel 1" behind the face of the wheel. You can see in these pictures that such an offset would reasonably put the centerline of the wheel in vertical alignment with the bearing behind the hub face. Note also the large hub ring visible on the left image.

Going to the tire for a moment - the supporting force from the road is distributed along the tire, but can be approximated for this discussion as a single force at the centerline of the tire. When the centerline of the wheel is well aligned with the bearing, the downward weight of the vehicle directly opposes the supporting force from the road. This is good, because the types of bearings used in wheel bearings are very good at supporting radial loads like this. Because they are aligned, there is no "twist" or "bend" being applied to the bearing.

If you change the offset of your wheel or install a wheel spacer, you are moving the centerline of the wheel away from its original location. Now, unfortunately, the vertical road force does not align with the downward vehicle weight, so there is now a "bend" force (called a "moment" in engineering). Some bearing types / arrangements do not accept this type of loading very well, and you will see very accelerated wear and failure. Some bearing arrangements are more tolerant of moment loading.

In any case, the radial forces are the same strength, the road force has just been moved outboard.

Hub-centric vs Lug-centric (the shear problem)

Although the radial forces are the same, it may not act on the same components. Hub-centric spacers have matching grooves and lips so that the wheel is positively centered on the hub, and the force is transferred by the spacer and hub lip / ring sets to the suspension. If the spacer does NOT have a lip for the wheel, then the wheel may not be centered, and the vertical force is carried only by friction with the spacer or the lug bolts themselves. This is where shear becomes a problem, because the bolts are actually intended to clamp, not to support the vehicle weight and road forces (although their single-shear strength may be high enough to seem otherwise). Six lug bolts may work fine for carrying 1/4 of your trucks empty weight, but add in some hits from large bumps / objects, and you could have a problem. You may also notice some excessive vibration if the wheel is not exactly centered.

Other notes

1) If you run a lift and/or larger tire, you may be able to correct your scrub radius using spacers. Scrub radius changes based on wheel diameter. Basically, with spacers you may be able to correct some handling issues caused by your larger tires.

2) A concern with spacers that is not a concern with negative offset is the tightness of the spacer nuts. While lug nuts can be checked with the truck tire on and truck on the ground, the nuts holding the spacer onto the wheel hub cannot.

3) Some aftermarket wheels have large hub holes to accommodate the hub lips of many vehicles. This effectively means they are lug-centric, and all the issues associated with lug-centric spacers apply to the wheel.

Supreme Pizza · September 20, 2017

Might have already been covered, but make sure you follow the torque specs exactly. Too much torque will cause them to fail. The manufacturer will provide instructions and torque specs. Wheel spacers are illegal in some areas because people don't install them correctly. Make sure you know what your doing.

The last set I installed wanted 82 lbs of torque.

Install, torque, drive 10 miles, torque, drive 10 miles, torque, remove and re-install with blue Threadlocker, torque, drive 10 miles, re-torque before thread locker dries. Then don't touch them after that - no re-torquing beyond this point.

These are not instructions for you to follow. These are not the instructions provided by your wheel spacer manufacturer.

Spurshot · September 20, 2017

From the link:

...

That being said, they will add a moment to the wheel bearings.

Just a moment.

Engineering, line 2.

Penguin VII · September 21, 2017

I hope the below may help to provide more detail and clarification to what others have already said.

...

That is some great information! Thank you for taking the time to write that all out and include visual aids. Gives me a much better sense of whats going on here.

As a hopefully quick follow up I'm curious to know if there is any way to tell how much additional stress I'm putting on my wheel bearings with these spacers. I'd imagine that wheel offset has a part to play obviously, as does width of tire. Am I correct in assuming that if the tire is center aligned with the bearing that even if the offset is more extreme it will have less wear? (more or less)

If so I wonder if there is any way to know roughly how much quicker your bearings will fail with spacers vs without, all things considered.

Truth be told I think I'm becoming more interested in the engineering part of this discussion than just trying to figure out if I can use these spacers.

Supreme Pizza · September 21, 2017

One of my rigs sat kinda funky after a lift kit, and I didn't like the way looked at all. It was "positive camber". (See pic) After I installed the spacers, it was sitting at "zero camber" - Perfect... I assume it had something to do with the interdifferential harmonics of the cluster harness. It probably diluted the fluid between the incumbust pitman arms and the infusion booster. Assuming the harmonics of the custer branch was ..... "fruzy" for lack of a better word.

Slugworth · September 21, 2017

Great Info!!!

Supreme Pizza · September 21, 2017

All kidding aside though, they did help the stance of the vehicle tremendously. The tires sat flat, and it gave the width that the vehicle needed. Nice upgrade at a reasonable price.