just received my 630 chain (EK chain, cheapest non o-ring) and 630 sprockets (JT 15T front and 41T Rear) kit ..
compared to the new JT sprockets, my old sprockets on the bike were just fine and not worn out at all .. however, the old chain was 1/2 to 3/4 link longer than the new one ..
since i got the el cheapo RK non O ring chain, i installed it without replacing the sprockets ... i dont care if they wear out in the next 15-20 k miles or even less as i could not justify replacing sprockets that were like new .. i might do the whole 530 mod next time around..
I am going to sell the brand new sprockets .. anyone want new in the box JT spockets 15T front ($23) and 41T rear ($33) for your 630 chain ??