Originally Posted by
Andrew R Stewart
Worn chains and cog skip under loads are completely different issues from the tight/loose cycles of chain tension in a non spring loaded tensioner system (single speed or fixed gears). Also ring lateral "trueness" has nearly nothing to do with chain tension. Lastly was the old ring an even tooth count one? If so then no wonder the teeth wear pattern is alternating, the chain has inner then outer plates which contact the teeth. An even toothed ring will have the inner plates only touch every other tooth. Had the ring been an odd tooth count I suspect the wear would have been more even (bad pun) Andy
42 tooth chain ring. The worn valleys are
not alternating,
but only on one half circle of the chain ring. Say, 22 teeth in a row all okay, 20 teeth in a row with bulged out valleys only on the right side of the chain ring as mounted on the bike.
The chain line isn't perfectly straight. The rear sprocket (20T) is offset to the right about one chain width compared to the chain ring.
Edit to add: The wear in the valleys between the chain ring teeth appears to be from the chain rollers. Sorry that I don't have a better photo.