I have tried to remove the drive side cotter pin and it is pretty tough, I didn't press the issue (NPI). This bike has been tinkered with I am sure, the cotters on each side are not the same and I think the chainring is installed backwards. I was given a spare chainring, a matching original with the bike, 26 tooth. The one on the bike is a 24 and the cog has 8. The 26 is in much better shape since it was not on the bike.