Originally Posted by Andrew R Stewart

I beg to differ. The tighter the chain the quicker the BB and rear hub (and/or freewheel/freehub) bearings will wear out. The tension set up you suggest will only share chain roller/tooth sharing (of the stress) until the chain wears and then you're back to where only one tooth/link sees the stress. I'll also speculate that when the chain is under tension (with no pedal forces) it and the cog are both wearing even when soft pedaling. So in my experience a too tight chain has more friction, wears faster, makes more noise and the only possible redeeming advantage is it won't tend to derail when raggedly powering the bike. Andy (waiting for the flames to start)