Some PF30 bottom brackets, such as the SRAM and the Wheels Mfg Angular I just bought have a sleeve in the middle. This could help save the bearings if you get water in the tube, since it would seal out the elements.

On BSA bottom brackets I have always removed the middle sleeve, finding it pointless.

Is this truly necessary on a PF30 BB to keep it aligned and prevent creaking, or is it just to keep water out (I will never get water in my tubes).

If it's not needed I'd like to cut it out of my Wheels Mfg BB, since it's pretty heavy with it (118g vs ~83g for the SRAM it replaced).