Brake disc retaining bolts

That little pin is kinda like a wheel hanger, simply to make installing the wheels easier. It can (and is often) just removed and discarded.

 

I actually find them helpful when installing wheels, used as a purchase for the rim.

I like to keep all parts original (or high quality upgrades) and in original position as it’s a bit of an indicator as to how the car has been serviced and maintained.

Why would they be left off, do folks feel they are in the way or something?

-ray

 

Folks use one of the aftermarket sets of wheel hangers that fit in the wheel bolt threaded holes. Wheels are very easy to mount with one or two of those.

 

They make putting wheels back on much easier, as others have said.

 

I think BMW's are the king of unnecessary engineering. That locator pin is another one. It is especially not needed with stud in hub design. Have you ever noticed sometimes it's kinda hard to hold a 50lb wheel/tire on the hub and get the bolts lined up with the holes? Now imagine the rotor also able to rotate on hub then you add wheel/tire and you got more holes out of alignment to line up. That's what that pin is for so that you can only have the wheel/tire offline to the hub holes. The pin also prevents the rotor from falling off when you take the wheel off which is a toe breaker if you got the car on a lift. Many times this isn't an issue when the rotor corrodes a bit and locks onto the hub. But a well maintained car with nice free wheel bearings that little pin can be a convenience.

On some wheels they are not cut out fully and you have to index the wheel on the pin too. then the pin is a pain. Sometimes there is no pin but just a hex bolt that will protude but sit in the flat of the wheel cutout. I have never found the pin to be big enough to be a tire placement aid. If I need that for a heavy tire I'll put in a screw in stud hanger.

 

Those pins are actually pretty important if you have ccm rotors. Biggest risk of damage to the rotors are present when mounting/unmounting wheels, since there are no studs and the CCM's are not very impact resistant. That little pin could save your rotor is the wheel slips during mounting.

 

These wheel hangars/guides are worth every penny to keep from chipping the CCM rotors. Helps with getting the wheel studs started also.
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Yup, much better than the dinky OEM bolts.

 

Correct. The ones that come in Porsche factory toolkits fit fine and are plentiful on eBay.

 

Sticky RX sells them, too, but I note they are currently sold out.

(2-Pack) Wheel Mounting Tool, M14 x 1.50 Ferrari and others. Also Know – Sticky RX Refinishing Solutions (**********.com)