I have ridden a DA7900 drive train for between 1000 to 2000 miles I guess. I have now just replaced the chain & cassette. The big ring has taken most of these miles and I wonder if I should replace this now (I have a spare on the shelf)?

There is a like a small lip around the circumference of the big ring at the bottom of the teeth - Is this a wear indicator? There does not look to be too much wear, but it's difficult to tell, even compared against the new ring.

There does not seem to be too much new chain movement on the used chainring, but will not swopping be detrimental to chain and then cassette life?

What chainring life are others getting?

1000mi?! Given proper care, you shouldn't have to replace even the chain. I take, admittedly, much better care of my bikes than most, but i get upwards of 4000 to 5000 miles on a chain - and 2 to 3 chains per cassette, and 2 to 3 cassettes per chainring set.

In short, what I mean to say is no - you shouldn't have to replace the chainrings.

Great - I won't swop it out then.

Good rule is change the chain every 2500 miles and the cassette every 10,000.

_________________
R2.5 / R3 / S-Works 29er (20 lbs) / S-Works SL4 Di2 (14.7 lbs)