they were just about new when got the chain, well i reckon 6 weeks at the most? surely cogs front and back, do you reckon i should replace the rear one? i never had this problem with a half link, i might try a kmc, although i tried an old kmc and i had the same problem, im not a fatty no tension is very tight if i dont have it very tight then its worse it is annoying, in that picture looking at the chain alignment, i moved it last night slightly to see if that works, i have moved the rear cog about 5 times but it still doesn't make a difference does everbody think new rear cog and chain?