Sounds like your chainring and sprocket are worn - I have had this problem - have changed the chain on my bike regularly but it has done about 8000 miles on the same chainring / sprocket so last time I put a new chain on it made the creaking / grinding noise you described. Don't worry, it will dissappear when your chain starts to wear.
Sounds like your chainring and sprocket are worn - I have had this problem - have changed the chain on my bike regularly but it has done about 8000 miles on the same chainring / sprocket so last time I put a new chain on it made the creaking / grinding noise you described. Don't worry, it will dissappear when your chain starts to wear.