Doing a Thin Wheel Spacer. Should I Consider Track Width?

[Saddlerocker]

Sounds like 1/4"-1" is the "need to modify" zone.
Under or over and good with stock studs.
Good to know. Thank you

 

[Shots]

You're welcome

 

[HSKR R/T]

6mm spacers should be okay, although they're right at the edge of what is considered safe.
10mm is too thick, and you won't have sufficient thread engagement. The thickest spacer you can fit on the DT and still achieve the minimum thread engagement is 7mm.

I went into detail on this on another thread. Here's a link to my post if you're interested → LINK

6mm may be fine as far as lug length goes but you will lose the hubcentric ring on the hub. Putting all the stress on the lugs themselves.

 

[Shots]

Correct, although how much effect it has beyond assuring the wheel is centered during installation, has been debated. I'm dubious about it's involvement in holding the wheel in place once everything is tight.
The principle force is applied against the face of the hub and the face of the wheel by the draw strength of the lugs/nuts. In order for the wheel to impart load onto the studs and/or hub lip it has to overcome the friction between the two. I've heard arguments for both sides saying the lip of the hub experiences little to no load because the face and lugs is where it's applied
I haven't gone into my software to explore this (it's not as easy as just plugging it in), but intuition seems to support this argument against the lip being much more than an install aid. Especially when I see aluminum hubcentric spacers that have a 1/4" of material sticking out. A thin little lip of aluminum doesn't instill a sense of structural integrity to me (I could deform/break that off with a hammer) so it sure seems to be an installation aid more than anything.
That said, all the force isn't on the lip, and it's not the same kind of force as hitting it with a hammer. I don't want say it's not doing anything because I don't know for sure, but if the lug nuts are tapered (or conical to be specific) the wheel should center around them (ie lug centric) and I suspect any clearance between the hub and wheel will be evenly distributed around that lip so it may not even be touching once the nuts are tight. Even if there is no clearance and the wheel and hub lip are in contact with each other, the wheel shouldn't be able to "shift" and impart load onto the lip because the studs and the two faces would be holding the wheel in place.
Again just shooting form the hip, talking through a hypothesis based on design aspects. Maybe one day I'll take the time to draw one up and to see if the physics simulation shows any load on the lip. I suspect it will be negligible if at all.

But you are correct, adding a thick spacer eliminates any effect the lip would have, including the installation aid if the spacer is too thick.

 

[HSKR R/T]

Correct, although how much effect it has beyond assuring the wheel is centered during installation, has been debated. I'm dubious about it's involvement in holding the wheel in place once everything is tight.
The principle force is applied against the face of the hub and the face of the wheel by the draw strength of the lugs/nuts. In order for the wheel to impart load onto the studs and/or hub lip it has to overcome the friction between the two. I've heard arguments for both sides saying the lip of the hub experiences little to no load because the face and lugs is where it's applied
I haven't gone into my software to explore this (it's not as easy as just plugging it in), but intuition seems to support this argument against the lip being much more than an install aid. Especially when I see aluminum hubcentric spacers that have a 1/4" of material sticking out. A thin little lip of aluminum doesn't instill a sense of structural integrity to me (I could deform/break that off with a hammer) so it sure seems to be an installation aid more than anything.
That said, all the force isn't on the lip, and it's not the same kind of force as hitting it with a hammer. I don't want say it's not doing anything because I don't know for sure, but if the lug nuts are tapered (or conical to be specific) the wheel should center around them (ie lug centric) and I suspect any clearance between the hub and wheel will be evenly distributed around that lip so it may not even be touching once the nuts are tight. Even if there is no clearance and the wheel and hub lip are in contact with each other, the wheel shouldn't be able to "shift" and impart load onto the lip because the studs and the two faces would be holding the wheel in place.
Again just shooting form the hip, talking through a hypothesis based on design aspects. Maybe one day I'll take the time to draw one up and to see if the physics simulation shows any load on the lip. I suspect it will be negligible if at all.

But you are correct, adding a thick spacer eliminates any effect the lip would have, including the installation aid if the spacer is too thick.

Going into theoretical hypothesis, adding a spacer, especially aluminum, without the lip could increase chance of a load in the lugs being enough to shear them as it would change the torque requirements to maintain that load bearing friction once the lug nuts are tightened. And granted, most dailt driving wouldn't be an issues as long as wheel gets centered. But any hard impact to the wheel/tire such at striking a curb, or offroading and hitting ruts/rocks could overcome the friction of the two faces being torqued together and bend/shear the lugs. Also meaning, in an accident, there is a better chance of wheel separating from vehicle than if you had the hubcentric lip.

 

[Saddlerocker]

Are OEM wheels not hub centric?
Feel free to tell me to go look it up, but I have factory Laramie Night Edition 22's and dont understand how the lip of a hubcentric spacer fits between the wheel/hub.

Isnt hub centric just meaning the spacer is made to fit snug around the hub? What is the purpose of the lip?

 

[Shots]

Yes OEM wheels are hub centric, however the hub lip is a bit under 1/2" with roughly 2mm of chamfer. The wheel bore will engage the unchamfered part, giving it about 0.394" (or 10mm) of contact. However, the wheel has a similar chamfer so the total usable engagement is roughly 8mm. If you install a 6mm spacer, you should technically catch the edge of the hub with 2mm (0.078") of overlap. That's minimal, but technically still engaged, which is why I wouldn't go any larger than 6mm.

Going into theoretical hypothesis, adding a spacer, especially aluminum, without the lip could increase chance of a load in the lugs being enough to shear them as it would change the torque requirements to maintain that load bearing friction once the lug nuts are tightened. And granted, most dailt driving wouldn't be an issues as long as wheel gets centered. But any hard impact to the wheel/tire such at striking a curb, or offroading and hitting ruts/rocks could overcome the friction of the two faces being torqued together and bend/shear the lugs. Also meaning, in an accident, there is a better chance of wheel separating from vehicle than if you had the hubcentric lip.

You're absolutely right, changing torque specs, various materials and/or eliminating the lip could absolutely have a trickle down affect. Like I said, I've heard compelling arguments for both sides. It would be interesting to see what the actual impact of minor changes would be, and where the threshold is. I just don't want to spend the hours drawing it up to "test" it.

 

[Shots]

Are OEM wheels not hub centric?
Feel free to tell me to go look it up, but I have factory Laramie Night Edition 22's and dont understand how the lip of a hubcentric spacer fits between the wheel/hub.

Isnt hub centric just meaning the spacer is made to fit snug around the hub? What is the purpose of the lip?

Part 2 of your question. It wouldn't fit between the wheel and hub, nor would there be a need for a lip if it's thinner than the hub's lip. A typical "hub centric spacer" is wider than the lip and reduces the inside diameter after it clears the hub. Then can have one of it's own so the wheel still mounts hub centrically onto it. Thus the spacer is hub centric on the truck, and the wheel is hub centric on the spacer. Examples seen here ↓↓↓


A hub centric ring is used to adapt an aftermarket wheel with an oversize bore to fit hub like the stock wheel. Doing so allows the mounting face of the new wheel to sit in the same place as the stock wheel, while the ring fills the gap between the wheel and hub. Thus making the oversized aftermarket wheel act like a wheel made to fit that hub. Examples seen here. ↓↓↓

 

[Saddlerocker]

Very much appreciate the info Shots.
I fully understand now, thank you.

 

[Bt10]

Thread end up on both.

Rings and lips for installation. When trying to use a thin spacer and OEM studs for attachment, the leverage on the studs is increased, but 6mm should be fine on that reason. However, the post above describing the lug centric friction between the faces is the answer.