Xl or standard load tyres

[GrahamHR]

The only way the centre spigot could support the weight of the wheel is if it was in direct contact for the whole circumference of the wheel centre bore, i.e. the wheel and spigot were manufactured such that they were an interference fit. If that were the case, wheels would require pullers to remove them ( and the use of wheel nuts with a taper would not be required).

Also, plastic spigot ring adaptors would not work; if the car was standing still for even days, the polymer in compression ( taking the load) would creep, meaning the ring at the opposite side would no longer be in contact with the spigot.

As to the bolts, why should they stretch and bend ( unless they were overtightened) ? They are arranged symmetrically, each would experience the same loads

[Tannaton]

Originally Posted by GrahamHR

The only way the centre spigot could support the weight of the wheel is if it was in direct contact for the whole circumference of the wheel centre bore, i.e. the wheel and spigot were manufactured such that they were an interference fit. If that were the case, wheels would require pullers to remove them ( and the use of wheel nuts with a taper would not be required).

But it is.... that's why sometimes it's tricky to remove wheels that have been on a car for a long time, and sometimes wheels that have been refurbished are tricky to get on.

Bolts that have a single point of attachment (i.e. don't slide through a bracket) are usually not used alone for shear loads, only tension.

I know you can get plastic spigot rings on e-bay but I wouldn't touch them.

[GrahamHR]

Wheels that have been on a long time have probably some corrosion in the centre borey, as would the spigot. I imagine it is those corrosion products that would lock the wheel to the spigot, not an intentional interference fit.

The bolts pass through the wheel, so isn't the wheel effectively acting like a bracket ? Once the bolts are fully tightened and the tapers have the correct contact pressure, it is the bolts that prevent the wheel moving relative to the hub.