I would like to dicuss PROS and CONS of 2 method for chain tension for single speed.
Chain tensioner with Bolt (left upper and left lower image).
Chain tensioner with a kind of spring + arm + roller (right image).
What comes to mind, that 1 method is more minimalistic and more "esthetic". While its cons, that each time when chain stretches a bit, you need to adjust bolt and axle position and maybe also to adjust bit a V-Brakes.
What are CONS of chain tensioner with spring + roller ? Is there any other considerations ?