Kind of a newbie question:

I'm planning on purchasing a new cassette for my Cervelo P2 and putting the old one on a rear tire that I plan to keep skewered on my indoor trainer. This will allow me to make the transition from trainer to riding outdoors little simpler.

Should I go ahead and purchase a new chain as well with the new cassette. Current cassette is shimano 105 11-25. I plan to put this cassette on my trainer wheel and replace it with ultegra 11-25.

Thanks for the assist!