What is this screw? Swapping 21" for 19" and found this loose screw. [pic]

[SharpKnife]

While attempting a tire change, this screw came out into my hand. I assume I should screw it back in, but how tight and what is it for? And should there be 3 more.?


This is part of a larger story of getting new 19" T Sportline wheels for my 2021 MYP, but hearing a creaking sound after the Tesla mobile tech replaced all four wheels. I got some tools to swap back to the 21" wheels, and when I went to replace the back rear, I found the problem - loose lug nuts!!! Never got tightened properly. Now I want to tighten them, but I am confused by the screw.

 

[GtiMart]

That is typically a screw that maintains the disks straight in place while the car is built. They eventually get frozen in place and need an impact screwdriver to get out. Yours doesn't have a screw head but that's what it's used for. It's not a mandatory part, the disk is held in place by the wheel. You can put it back if you want.
Maybe others can chime in, I'm not the absolute reference, but that's what I undersstand.
EDIT: To be clear, its torque spec isn'T that important.

 

[804son]

It's the retention bolt for the brake rotors when the vehicle is getting assembled, just tighten it up with a 10mm wrench, if you are running the stock wheels. It can be removed if you are running aftermarket wheels that would not otherwise sit flush.

 

[gixxer614]

As previously stated, it is purely there in the manufacturing process to keep the brake rotor in place until the wheels are installed...typically a final step. Tighten snug or discard if you like. It serves no real purpose after assembly.

 

[SharpKnife]

Very much appreciated guys! I’m gonna take it out and put new 19” inch back on, with properly tightened Lugnuts.

 

[patnshan]

I found this out because Tire Rack actually gave me instructions to remove those and toss them, when mounting my new winter wheels.

 

[Wolfhausen]

Don't toss them. They hold the brake disk to the hub and ensure alignment with the wheel lugs. When you torque the wheel and lug nuts on the car, the lug nuts provide the pressure to hold the disk to the hub. When you remove the wheels, that force is no longer there, and the disk could loosen from the hub. The brake caliper would prevent the disk from falling off the hub, but there is no reason to remove that bolt. Just snug it back up to maybe 20 ft/lbs.

 

[mrwug]

Do the T Sportline wheels accommodate the bolt? My understanding was that most aftermarket wheels don't fit with it in place.

I have a set of TST's on order.

 

[Wolfhausen]

If not, there is a hex key alternative that sits flush with he disc. Just make sure you get the right length, diameter, and thread pitch.

 

[Mike0187]

I randomly came across this screw when I was putting on my new wheels the other day. Good to know it not that important but I did screw it back in place because it was really loose