Increasing center bore of alloys

[Chip-mk1]

I'm a curious chap so I'll probe further. Firstly, that 5 tonnes shear force is a static load, the studs under go fully reversed fatigue loading. This probably isn't a problem as shock loading will be more than double what "generic" loading is and steed has a beautiful endurance limit. I'd also be very surprised if you couldn't generate some ridiculous shock loads through, think hitting a pothole hard. Bolts are also by nature covered in stress raises.

Finally, if this is the case then why are hubcentric spacers even a thing? I've been heavily involved in upright/hub design and manufacture for a race car before and have seen hub failures due to not using spigot rings, though we do have a pretty marginal factor of safety on some things. We always use the spigot to locate and take load.

Edit:
On hubcentrics being a thing, bar the need to centre the spacer on the bolt to hub type.

Sorry but I simply dont believe you that the lack of spigot ring caused a failure, like ive said already its just a nont inteference connection into at best ally and at worst often plastic, there is just NO way that is going to take the loads if the bolts dont, and it wont take a single NM of load until after the bolts have allowed movement, and by then it really is too late, I guess there is the theory that it *could* have a really slight effect, like my example of a t-shirt over a bullet proof vest in theory there is a circumstance out there where you get penetration of the vest *just* and a t-shirt would be enough to stop it, but to try and design to that level of accuracy would be ludicrous on a wheel fastening, you would just make the bolts 0.01 mm bigger or whatever instead for the same amount of extra support, lol

I use hubecentrics for convenience but I have also run completely without spigot rings both on the road and on track and the bolts were enough, and if they ever werent I would move to a better grade of bolt not rely on a plastic ring!

 

[Alex Conway]

I'll try and find a picture of the failure, personally it just doesn't seem right to me, I would be very surprised if the centre spigot didn't play a role. To have it not play a role goes against my gut and a lot of stuff I've been taught/come across. When you talk about the tolerances that the ring would have to be manufactured to in order to have a point then what tolerances are your bolt holes/tapers to on the wheel and hub? There are four of them so for them to perfectly line up you would have to have to be high level of tolerance between them. Tolerances between concentric diameters are much easier/cheaper to get right then holes on a PCD! Finally, since you run a stud conversion kit, would you be happy running studs 20mm longer with a 20mm blank spacer between them and the wheel? One which provided location for itself (as to not unbalance the assembly) but no location for the wheel. Seeing as you would have studs there would be no need for the spigot in your eyes.

Cheers for continuing the conversation!

 

[Chip-mk1]

The nuts/bolts are a taper fit into the wheel, so by definition they will always locate positively when tightened (ie akin to an interference fit in terms of zero movement is possible before contact to transmit load)
Its only if they are loose that any load would be transmitted into the spigot ring instead, and once that happens you've got a problem spigot ring or not.