Centrelock Wheels on Road Cars

[duncs500]

It is a different load path / profile isn't it? Any eccentricity on a centre lock is loading up the top and bottom of the thread more in opposite directions (moreso on cars with a bit of camber) eg. the rotation / torque applied to the eccentric wheel is therefore greater against the threads. With small nuts/bolts the rotation of the looser wheel is giving more of a pull out force as opposed to loading the individual threads. Albeit majority of the force is shear, I think it's about the risk of eccentricity changing that.

Could be bollocks and obviously very small margins, but could be a safety factor thing.

[V8Granite]

Metal moves a lot.

We have a PTO flange roughly half a metre diameter.

It is still not perfectly centred while we slowly torque the bolts opposite each other from 50Nm up to the final torque. Normally around 600Nm it's barely able to be moved and lots of times you need to loosen them all and start again We can make it sit high or low wherever we want (which is what you do to get the shaft alignment perfect) up to the final torque of 1100Nm.

Now, whether you would notice it being 3 hundredths out of square is very unlikely but it is probably not perfect flat.

It's one of those things where it's the proper way to do it but other ways don't show any noticeable negative.

Now if they put copper grease on the threads aswell, I expect it to explode upon starting.

Dave!

[integrale_evo]

Wheels are centred on the hub, oem wheels are machines to be a snug fit, aftermarket wheels should have spigot rings to help centralise the wheels.

Most centrelocks have a nose behind the threaded part which does the centralising. Like a normal wheel you’re not relying on the taper of the nut / bolt to centre the wheel, they’re to help it sit square against the hub as you tighten it.

[Swervin_Mervin]

I can't see how, with a centralising hub arrangement, that snugging it up in the air and then torqueing on the ground is going to result in any issues.

Having it hang, subject to gravity, is going to knock it off-centre initially and that's no different in either the snug on the ground or in the air.

The only true way to centralise it would be to turn the car on its side so the wheel is horizontal

Sounds like some more classic Porsche bullshit to me.

[mik]

Sounds like some more classic Porsche bullshit to me.

You also have to tighten them with a K-Rated torque wrench, set to SNm (Stuttgart Newton Metres).

[Marv]

F1 cars get their wheels changed with the car up in the air, so that's the only way to do it, IMO.