► Official APEX VW SM-10 Flow Formed Wheel Thread

[APEXWheels]

Geirsen would Apex consider the Porsche style lug nut/ lug bolt that has the r13 ball seat as a built in washer?
So you can get a more accurate torque and protect the finish of the wheel where the lug nut/bolt Seats?

View attachment 211880

It's funny that you brought this up, as I was just discussing this option with our engineering team. We are planning on offering OE style R13 lug bolts (and nuts for the stud conversion kits) but if the demand is there, we might also offer this style alongside the OE hardware. As you noted, the pros of having the washer style lug bolt/nut is a more accurate torque spec and less of a chance of nicking the finish in the lug recess. The only downsides would be the increased cost and the fact that they are a bit taller and tend to protrude out a bit more than the OE-style hardware. Once I have a chance to finalize the details, I will have some samples ordered to test fit with our VW SM-10 wheels to see how they look. I'll get some pictures posted once that happens.

-Geirsen

 

[jmblur]

It's funny that you brought this up, as I was just discussing this option with our engineering team. We are planning on offering OE style R13 lug bolts (and nuts for the stud conversion kits) but if the demand is there, we might also offer this style alongside the OE hardware. As you noted, the pros of having the washer style lug bolt/nut is a more accurate torque spec and less of a chance of nicking the finish in the lug recess. The only downsides would be the increased cost and the fact that they are a bit taller and tend to protrude out a bit more than the OE-style hardware. Once I have a chance to finalize the details, I will have some samples ordered to test fit with our VW SM-10 wheels to see how they look. I'll get some pictures posted once that happens.

-Geirsen

<Enginerd>
One more benefit - standard bolts over-constrain the wheel. It's already aligned on the center bore and wheel face, so it only needs holding force inward and control over rotation (tangential about center bore) for full constraint. Each ball or conical bolt or nut also adds constraint radially and tangentially... So with 5 of those PLUS the center bore, the only way this works is through elastic averaging... Or as is the case with wheels, often plastic averaging (the lug seats permanently deforming). This can lead to lug nuts loosening up after initial installation as well as the wheel finds the lowest energy state between all the over-constrained bolts.

</Enginerd>

 

[Raguvian]

<Enginerd>
One more benefit - standard bolts over-constrain the wheel. It's already aligned on the center bore and wheel face, so it only needs holding force inward and control over rotation (tangential about center bore) for full constraint. Each ball or conical bolt or nut also adds constraint radially and tangentially... So with 5 of those PLUS the center bore, the only way this works is through elastic averaging... Or as is the case with wheels, often plastic averaging (the lug seats permanently deforming). This can lead to lug nuts loosening up after initial installation as well as the wheel finds the lowest energy state between all the over-constrained bolts.

</Enginerd>

 

[burgerkong]

<Enginerd>
One more benefit - standard bolts over-constrain the wheel. It's already aligned on the center bore and wheel face, so it only needs holding force inward and control over rotation (tangential about center bore) for full constraint. Each ball or conical bolt or nut also adds constraint radially and tangentially... So with 5 of those PLUS the center bore, the only way this works is through elastic averaging... Or as is the case with wheels, often plastic averaging (the lug seats permanently deforming). This can lead to lug nuts loosening up after initial installation as well as the wheel finds the lowest energy state between all the over-constrained bolts.

</Enginerd>

Except that isn't true. Your underlying hypothesis is that the lug bore centers aren't drilled exactly on a 112mm bolt circle, and that the person doing the final torquing is doing it on the ground while the seats haven't even contacted the wheel. If this was the reason for floating seats, please explain why BMW has never had floating seats.

Floating seats are used when tolerance cannot be maintain, or is questionable as is with some aftermarket products and if seat finish is important (especially on very expensive wheels). They allow for slight deviation from the 112mm (or any other PCD). A more severe case is PCD variation/wobble bolts - a good OEM replacement does not need such allowances.

Floating seats are not meant to induce another degree of freedom into the bolted joint since now axial load is being put on the hub pilot via the hub ring (if using) which is being relied on as an absolute centering aid (which now requires zero slop). This is one area where you don't want that happening (again, assuming the machining of the PCD is within specifications).

Moral of the story, don't buy questionable wheels.

 

[jmblur]

Except that isn't true. Your underlying hypothesis is that the lug bore centers aren't drilled exactly on a 112mm bolt circle, and that the person doing the final torquing is doing it on the ground while the seats haven't even contacted the wheel. If this was the reason for floating seats, please explain why BMW has never had floating seats.

Floating seats are used when tolerance cannot be maintain, or is questionable as is with some aftermarket products and if seat finish is important (especially on very expensive wheels). They allow for slight deviation from the 112mm (or any other PCD). A more severe case is PCD variation/wobble bolts - a good OEM replacement does not need such allowances.

Floating seats are not meant to induce another degree of freedom into the bolted joint since now axial load is being put on the hub pilot via the hub ring (if using) which is being relied on as an absolute centering aid (which now requires zero slop). This is one area where you don't want that happening (again, assuming the machining of the PCD is within specifications).

Moral of the story, don't buy questionable wheels.

I design precision machinery (double digit micron repeatability at 1g accelerations). Nothing is ever "perfect", it just depends on what scale you're measuring. Trust me when I say unless you're using extremely expensive manufacturing techniques, you're going to see positional tolerances on the order of +/-50 to 200 microns at a 112mm bolt circle depending on machine setup, tooling, and process. Add into that form tolerances in both the bolt radius and bolt holes and you get a surprising amount of overconstraint. We're not taking millimeters off here, but it doesn't need to be.

Floating collars only float during initial installation - once they're fully seated and torqued, the friction of the bolt surface holds the floating seat in place. There is no load on the hub centering ring once the bolts are tightened properly, regardless of floating collars or not, all load is carried through friction. If you're carrying anything but axial load in your bolts you're going to have a bad time.

The hub pilot itself is always going to be the best reference because it's a turned feature, and almost always done in the same setup as the bearing locating features, keeping the tolerance loop extremely tight. The hole drilling on the hub will be pretty good because it's done on a live tool in the same lathe step, but drilling isn't as precise as turning.

The reason BMW has never had floating seats is because of cost. They're not a huge upgrade, they're never going to be noticed by a normal driver, and the benefits basically come down to slightly better centering, reduction in bolt loosening, reduction in galling on the bolt seats through repeated wheel changes, and more accurate bolt torque. Porsche doesn't spec them because they're making shitty OEM wheels, they spec them because they're a superior engineering solution. Just not so superior most companies consider it worth the not insignificant cost increase.

 

[trashb0y]

forgive my ignorance, this is my first time buying a set of wheels. do i need to buy any additional hardware (lug nuts), or can i just use the ones from my factory wheels?

 

[Will_]

forgive my ignorance, this is my first time buying a set of wheels. do i need to buy any additional hardware (lug nuts), or can i just use the ones from my factory wheels?

These wheels will work with your factory wheel bolts.

 

[jmblur]

These wheels will work with your factory wheel bolts.

But then how will you get into a super nerdy argument about machining tolerances, kinematics, and gd&t????

 

[trashb0y]

These wheels will work with your factory wheel bolts.

thanks! excited for these

 

[burgerkong]

I design precision machinery (double digit micron repeatability at 1g accelerations). Nothing is ever "perfect", it just depends on what scale you're measuring. Trust me when I say unless you're using extremely expensive manufacturing techniques, you're going to see positional tolerances on the order of +/-50 to 200 microns at a 112mm bolt circle depending on machine setup, tooling, and process. Add into that form tolerances in both the bolt radius and bolt holes and you get a surprising amount of overconstraint. We're not taking millimeters off here, but it doesn't need to be.

Floating collars only float during initial installation - once they're fully seated and torqued, the friction of the bolt surface holds the floating seat in place. There is no load on the hub centering ring once the bolts are tightened properly, regardless of floating collars or not, all load is carried through friction. If you're carrying anything but axial load in your bolts you're going to have a bad time.

The hub pilot itself is always going to be the best reference because it's a turned feature, and almost always done in the same setup as the bearing locating features, keeping the tolerance loop extremely tight. The hole drilling on the hub will be pretty good because it's done on a live tool in the same lathe step, but drilling isn't as precise as turning.

The reason BMW has never had floating seats is because of cost. They're not a huge upgrade, they're never going to be noticed by a normal driver, and the benefits basically come down to slightly better centering, reduction in bolt loosening, reduction in galling on the bolt seats through repeated wheel changes, and more accurate bolt torque. Porsche doesn't spec them because they're making shitty OEM wheels, they spec them because they're a superior engineering solution. Just not so superior most companies consider it worth the not insignificant cost increase.

Before you go and pat yourself on your back, tolerance is inevitable. However, repeatable tolerance is what all manufacturers aim for. It's also a deep hole because while you may say non-floating seats over-constrain the joint, the assumption that the hubcentricity of the centerbore is without tolerance, again is fallible. There are no wheels that have an interference fit between the centerbore and the hub pilot. It just can't be done because of tolerance. So how can floating seats fix bad tolerance because now the issue migrates to whether the centerbore was machined bang on center - otherwise we are translating the wheel by microns thus affecting the concentricity of it, to the hub itself.

I agree, the slip-critical joint on wheel/hub surfaces by design requires studs or bolts to see only axial force. However, the case can be made that the floating collars allow the loose fit of the hub centerbore to make contact on one specific point. Now we're introducing axial load onto the bore. At the end of the day, floating collars are used not because it's 'superior engineering', but for other benefits, such as gall-prevention, non-marring and the ability to make minute lateral shifts. However, if you assume there is going to be shifting because your machining tolerance is non-repeatable and random, you have bigger issues.

Sorry to rain on your parade, but most wheel production has shifted to full CNC milling, a lathe is only used mainly for flow forming. The PCD is machined at the same operation as the centerbore using tooling with a stationary workpiece. Moving the work piece requires precise fixturing - good for low production runs, but not for mass production.

 

[jmblur]

Before you go and pat yourself on your back, tolerance is inevitable. However, repeatable tolerance is what all manufacturers aim for. It's also a deep hole because while you may say non-floating seats over-constrain the joint, the assumption that the hubcentricity of the centerbore is without tolerance, again is fallible. There are no wheels that have an interference fit between the centerbore and the hub pilot. It just can't be done because of tolerance. So how can floating seats fix bad tolerance because now the issue migrates to whether the centerbore was machined bang on center - otherwise we are translating the wheel by microns thus affecting the concentricity of it, to the hub itself.

I agree, the slip-critical joint on wheel/hub surfaces by design requires studs or bolts to see only axial force. However, the case can be made that the floating collars allow the loose fit of the hub centerbore to make contact on one specific point. Now we're introducing axial load onto the bore. At the end of the day, floating collars are used not because it's 'superior engineering', but for other benefits, such as gall-prevention, non-marring and the ability to make minute lateral shifts. However, if you assume there is going to be shifting because your machining tolerance is non-repeatable and random, you have bigger issues.

Sorry to rain on your parade, but most wheel production has shifted to full CNC milling, a lathe is only used mainly for flow forming. The PCD is machined at the same operation as the centerbore using tooling with a stationary workpiece. Moving the work piece requires precise fixturing - good for low production runs, but not for mass production.

You're reading half of what I say and assuming the rest. Never did I say the wheels were turned, I said the hub was turned. You need to consider we're not talking about dialing in one machine, it's thousands of mills and lathes over tens of years all making parts that need to work together. You can't just say "repeatable tolerance" without considering the statistical spread of CP and CPK across different machines. But if you're not following on the simplified version we won't get into six sigma here.

Not going to pollute this thread any more since I'm just going to be repeating myself, but the science of kinematics and constraint and designing around manufacturing tolerances is super interesting. I'd highly recommend reading into it more. Slocum is a good starting point.

 

[burgerkong]

You're reading half of what I say and assuming the rest. Never did I say the wheels were turned, I said the hub was turned. You need to consider we're not talking about dialing in one machine, it's thousands of mills and lathes over tens of years all making parts that need to work together. You can't just say "repeatable tolerance" without considering the statistical spread of CP and CPK across different machines. But if you're not following on the simplified version we won't get into six sigma here.

Not going to pollute this thread any more since I'm just going to be repeating myself, but the science of kinematics and constraint and designing around manufacturing tolerances is super interesting. I'd highly recommend reading into it more. Slocum is a good starting point.

Noone is going in depth into this, we don't even have data for the factory APEX utilizes, plus the make and model of machines, plus the tooling, let alone their QC stats.

On a broad level, you're hyper focused on the over constraint aspect of this discussion. Again, if you add back that degree of freedom, it doesn't mean the rest of the assembly has the same amount of precision let alone tolerance. The threading in the bolts have a certain fit, the hub has a certain tolerance etc etc. Just because the lug seats are free to float around doesn't mean the wheel is concentric (which in itself has tolerance as well), which should be the ultimate goal. It becomes a matter of what is prioritized - do you make everything so precise that its over constrained (which I argue is not the case)? Or do you use the inherent slop in all the associated parts and conclude that floating seats aren't really necessary?

This is an overly simplistic analysis with some educated assumptions, yet it should bring my point across. Plus, I did read your entire reply. Rather, it is you that glossed over my very first reply - you hadn't addressed how the centerbore isn't 57.1mm +/- 0.01 micron thus if you use the floating seats to maneuver the wheel such that the seats make full contact, the wheel can be off center. Likewise, if the wheel isn't off center, that also means that the PCD was machined accurately, albeit off by the same amount in the same direction for each lug bore.

 

[theDoktor]

All right- all the engineers on this thread topic need to take a time-out and a 12 oz. chill pill or two!

 

[Johaan]

Anyone else just get charged the deposit today and get a notification to set password in the system? I got two separate emails.

I was wondering why the charge had not hit yet. Fine by me, punts payment to June…

 

[Tom Brohanks]

Anyone else just get charged the deposit today and get a notification to set password in the system? I got two separate emails.

I was wondering why the charge had not hit yet. Fine by me, punts payment to June…

I got mine the other week. I'm just impatiently waiting for the wheels to show up