Ok on my recent ride I encounter this new problem, my chain dropped when I shifted the chainrings, TWICE!. First time is when im changed it to a bigger sized chainring and its not a steep uphill at all, only a normal one and it fell. Ok the second one is a dangerous one. At the end of the trail there is a road going uphill when when i was going uphill, I changed my chainring to the smallest and there it goes again, it feel and to make matter worst there is a motorbike going uphill, i quickly push my bike (my saddle is quite high and my leg barely reach the ground). Do you think its time to change the chainrings? And My cranks somehow have a sound like a creaking sound when pedalling, my friend told me that my BB has broken so I was wondering, should I change my chainring only and my bb(ISIS) only or should i get a Deore LX/XT Crankset?