Chain tube noise?

none said:

Is there much noise from recumbents equipped with chain tubes? They're
the tube the chain runs through to keep oil, etc., off your legs.

It depends on the bike.
Sometimes the mounts are not good and you can make better ones (that
allow the tube to float on the chain better), sometimes you can remove
some or all of them, sometimes they can be replaced with roller idlers.

I had a SWB that came with a total of about 36 inches of chain tube, and
I found that the chain was basically impossible to clean without
breaking it and removing it from the bike completely, which I did not
wish to do. I cut away most of the chain tubes leaving only what was
necessary and got easier maintenance, and a reduction in noise and drive
friction as well. My current two bikes have no tubes, and I likes 'em
that way.

Some bikes use curved chain tubes, mostly on the return-run but either
way I consider to be a significant practical drawback.
~