I have a 2016 Cannondale that I use on a Cyclops fluid trainer. The bike was spec’d with a 50 tooth chain ring but I have found out that what is on the bike is a 48 tooth chain ring. Does this make a difference in the power numbers that are shown?
No, but it does affect your gear ratios based on your rear cassette.
It’ll make no difference at all to the power you can put out (you just will spin marginally faster perhaps and that will probably be balanced out likely by your use of the cassette), a smaller ring though is suppose to be more responsive to ERG.