Hi. Thanks. Yes, the outter chainring on the front. I think there are 8 cogs on the back but I am not now near my bike to check (at work as it is daytime here now). The problem happens when shifting to a harder gear.
Sorry, I will have to leave this forum now as I have to catch a train to teach a class outside Tokyo. It will be about 7 hours before I can get back to my computer. I will check again for any any replies at that time. Again, thanks so much for your help.
dkun