According to Urban Dictionary...

Muffler bearings

A real howl for prank-calling kids of our 70's past: get a naive auto parts clerk on the phone (dumb teen, etc.) and ask for "muffler bearings". A bigger howl when they realize the gag, and get back on the phone and cuss you out.

Muffler bearings


A fictional term that bullies use when they ask questions or give maintance advice to ricers.

There is no such thing as muffler bearings however most guys who know nothing about cars can easily be convinced that it is part of their maintance.
Ricer: Is there anything I need to know before I install my new exhaust system?

Bully: Make sure to grease those muffler bearings before the install (bully laughs under his breath)

Muffler Bearings

Contrary to popular belief, muffler bearings do exist, just ask your local dodge stealth or mitsubisi gt3000 owner. Although a popular prank to pull on the not so automotive savy muffler bearings are located inside the muffler, in order to operate a flap which opens and closes depending on the exhaust flow directing flow back into the turbo. Due to inconvienience (carbon/other buildup often jammed the bearings causing noise and poor performance) the bearings are only found on older models.

Hey go into the garage and grab the blinker fluid and spare muffler bearings!

 

See we were B.Sing you. They are real. lol

 

I'm so pulling that prank someday

 

Nope, you could run no muffler and still not require a tune...
Just as long as the OEM system is there up to and
a little bit past the last OEM O2 sensors......

 

Of course they are.
The joke is the greasing part...
They don't need to be greased, it's a self contained system.