Dammit’s adventures in mountain biking

First time I've tried it, chap who recommends it says the following:

The main benefit is eliminating wash out and sealing against contaminants. While you may use the thickest, heaviest water proof grease you can find on your BB threads, it's the bike wash/degreaser that enters your frame during washing through your seat tube, cable guides or any other frame holes that ends up sitting in your BB shell that breaks down the grease.

Teflon tape completely seals the threads from the inside and out and makes them water tight which is the reason plumbers use it to seal water pipes hence it also being called "plumbers tape".

It will also help dampen any noise and further prevent the BB from seizing and becoming stuck and if done correctly, will prevent you ever needing to service your BB again until the bearings need replacing. PS if you execute this well and your BB still creaks, it's not the BB. 😉

A few important details for installation:
Ideally start with clean BB shell and cup threads. If there is any factory applied preset loctite on the cups, it's usually fine to just tape over.

DIRECTION: Apply/wrap teflon tape in opposite direction to which the cup threads in (so tape tightens and end of tape doesn't lift during install)

AMOUNT: Just shy of 2 layers is optimal. It's best to create a slight low spot (gap) rather than overlap the end and create a bulge in the tape. I usually start at a logo on the cup and finish just short of it (see pic).

TECHNIQUE: Wrap tight and push tape into threads with thumb and fingers by rotating in your hand the direction in which the cup threads in.

GREASE: It's still very important, mainly to keep the tape intact during the install. As always grease both the shell and cups to eliminate all the grease either getting pushed in or extracted out during the install.

Cups should still thread in quite easily by hand.