Hoping one of you tech guys will know this one....

I just fitted a set of four steel winter wheels onto our '04 S60. On each cast iron wheel hub, there's a small bolt with a 10 mm head. It's located half way between two of the threaded lug sockets. Of course, the OEM alloy wheels have a cast recess that fits over the bolt head. The steelies have a dimple, but it's not deep enough to clear the bolt head, so I had to grind down about half the bolt's head.

My question: what is this bolt for? Is is merely for assembly purposes? After the wheel is bolted on, I don't see what the bolt's purpose is. Could it be removed altogether?

Thanks in advance!

 

I belive that's the bolt that keeps your rotor locked in place

 

Some people remove them but the rotor will flop around on the hub.

 

But not when the wheel is bolted on, right? I mean, it must be there just to keep the rotor from "flopping" on the assembly line, right?

 

Yes and when you remove the wheel.

Once the lugs are tight it is tight. I just like to leave them so the rotors don't move when taking the rims on and off.

 

It also allows you to hang the wheel when you are putting the tires back on.