Originally Posted by
Nbob
Before fiddling around with your limit screws - how old ( or roughly treated) is your chain. Shift to smallest cog and big ring then pinch the chain on the big ring at 3 o'clock then pull straight out towards front wheel. If it starts to fall off the teeth at the top of the big ring ..... there's your trouble.
Chain is new, less than 300 miles. But I will also do this test just in case.