Center Bore

[wparsons]

^^ You clearly either missed or ignored the link to the miata site where actual engineers chimed in with real world numbers and clearly stated that with lug centric wheels/lugs centering rings do nothing but hold the wheel centered while you tighten the lugs.

Also keep in mind that the only time there is a purely vertical force on the lugs is if you're running 0 camber with 0 offset wheels while at rest. The dynamic forces are all over the place and all rely on the lugs to hold the wheel in place.

[Anaxilus]

Originally Posted by switchlanez

Again, this entire debate boils down to this: Would you rather have 20 tiny studs holding your car up or 20 studs AND 2 massive axles?

False choice, the 20 tiny studs are in fact what always puts the weight on the both axles. If the weight of the vehicle is actually on that plastic ring after installation, something is more than likely wrong. See above.

[switchlanez]

I never said hubrings are necessary; only that they're better especially when $25 can save cars/lives.

I used to believe hubrings were purely for mounting and not loading purposes. As recently as earlier this week, when I advised my friend that he didn't need hubrings for his Enkeis so long as he mount them perfectly centered. Til this thread prompted me to look into it.

[switchlanez]

I read through that Miata thread. Saw opinions stating 20 studs support the weight alone and people stating the studs combined with hubrings will help some. My hubrings have a conical tapering so they fit completely snug with NO play *before* I torqued down my conical lugs. Hard to believe no load gets transferred through fully seated hubrings with 0 gap fitment.

I still say 20 studs/conical lugs + hubrings > 20 studs/conical lugs alone.

[switchlanez]

@aCab, @Anaxilus, @wparsons, lug-centric front wheels must be torqued completely off the ground to properly mount them to the FR-S/BRZ. So how do you do it?

[aCab]

Torque down does not equal torqued to spec.

[Anaxilus]

Originally Posted by switchlanez

I read through that. Saw opinions stating 20 studs support the weight alone and people stating the studs combined with hubrings will help some. My hubrings have a conical tapering so they fit completely snug with NO play *before* I torqued down my conical lugs. Hard to believe no load gets transferred through fully seated hubrings with 0 gap fitment.

I still say 20 studs/conical lugs + hubrings > 20 studs/conical lugs alone.

It's pretty clear that clamping force from the conical lugs is what puts the load on the actual hub and wheel mounting surfaces. If the hub center has to support any load after installation of a lugcentric wheel, something is mechanically wrong somewhere. The lugs mechanically position and glue the wheel to the hub, not the hub center. Deny it all you want, you'd be incorrect. But if the ring makes you feel better, go for it.

Originally Posted by switchlanez

@aCab, @Anaxilus, @wparsons, lug-centric front wheels must be torqued completely off the ground to properly mount them to the FR-S/BRZ. So how do you do it?

I admit I once found the task completely impossible for mere mortals, so I've since learned that sprinkling ground unicorn dust on my wheels does just the trick.

[switchlanez]

Originally Posted by aCab

Torque down does not equal torqued to spec.

Hand tightening lug-centric wheels before dropping the weight of the car does not sound reassuring. Especially when it requires both hands to apply forces that pull the wheel off-center as you hand torque the lugs instead of using both hands to hold the wheel centered as it's torqued.

Originally Posted by Anaxilus

It's pretty clear that clamping force from the conical lugs is what puts the load on the actual hub and wheel mounting surfaces. If the hub center has to support any load after installation of a lugcentric wheel, something is mechanically wrong somewhere. The lugs mechanically position and glue the wheel to the hub, not the hub center. Deny it all you want, you'd be incorrect.

I never denied clamping force plays a part. If it didn't, we'd have a serious problem. I also don't claim the hub center supports 100% of the load. I just don't see how no normal force (load) can get transferred when there's 0 gap at the hub rings. Especially when the clamping force applied by the lugs seats the wheel against the chamfer of the hub ring.

Originally Posted by Anaxilus

It's pretty clear...

But if the ring makes you feel better, go for it.

Does physics make me feel better than "pretty clear" speculated claims? Yes.

[Anaxilus]

Originally Posted by switchlanez

Does physics make me feel better than "pretty clear" speculated claims? Yes.

So when physics and engineering disagrees w/ you, it's just a speculated claim? Apparently ignoring real physics and engineering to rely on lucky charms makes you feel better too.

[switchlanez]

Originally Posted by Anaxilus

So when physics and engineering disagrees w/ you, it's just a speculated claim?

1) Please point out where he factors in shear strength of the studs. I might be overlooking where he included that. All his calculations focus on friction (tension) and that would be a huge oversight. Studs being 1.5 times weaker in shear than in tension (aka frictional clamping force) would make them the weakest link as demonstrated by the real life example I posted earlier; your guy seems to neglect shear force and focuses entirely on clamping force.

2) He assumes the thread's coefficient of friction mu and collar friction mu c to both be 0.15 with no reference to how that value was determined. An interesting coincidence: The textbook from my basic Physics for Engineering class used an assumed value of u=0.15 for the sample and homework problems in the chapter that introduced us to friction. Seems he used the same number here (aka pulled that number out of his ass). Actually quite hilarious and nostalgic (for me).

Originally Posted by Anaxilus

Apparently ignoring real physics and engineering to rely on lucky charms makes you feel better too.

Lack of calculations for shear and speculated coefficients of friction reduce his calculation to speculation making it invalid enough to ignore. Believing in how components are clamped against each other and transfer load (via hubrings) involves no luck nor odds.

[Cjymiller]

When I made the first reply to this thread, it was one notch from being bumped to page 2 of wheels and tires and forgotten forever. I had NO idea it would spark such passionate debate. Think about this. Hours have been spent in this thread putting forth perspective and reason.

Amazing.

[MikeR]

My dilemma. TRD wheels 54.1 center bore against 56.1.


http://vid1164.photobucket.com/album...307_084325.mp4


would hubcentric rings be my solution? Thanks for any info provided.

[cjd]

Originally Posted by MikeR

My dilemma. TRD wheels 54.1 center bore against 56.1.


http://vid1164.photobucket.com/album...307_084325.mp4


would hubcentric rings be my solution? Thanks for any info provided.

A hubcentric ring reduces the diameter of the wheel centerbore... You need to go the opposite way, no? That would require machining the wheel (you should't even be able to get it to sit flush)

C

[MikeR]

after more inspection, you are correct. It doesn't sit flush. Spoke to a shop about making an adaptor who quoted me 25 each a quarter of an inch thick. May try that as I would like to keep the wheels but may have to sell them which is a bummer. Just bought tires for them also.