On Mon, 10 Feb 2020 03:57:46 -0800 (PST), fred
wrote:

For various reasons I wish to run a thinnish pull cord via 4-5 pulley wheels. Does anyone know if smaller pulley wheels offer more resistance than big ones?

Yes.

1) Smaller will turn faster than bigger so there will be more turning
resistance (bearing friction).

2) Bending the cord though a greater amount will require more effort.

How much it will be more may be difficult to predict / measure though.
;-)

Cheers, T i m