1. Check your cassette
If your new trainer is from the flywheel category, you don't need to think about this point. But as long as you've got a direct drive model, read here carefully. Most trainers come without a cycling cassette, so you need to either buy one or use the one that’s mounted on your back wheel. We definitely recommend buying a new one because it means you’ll be able to transition easily between indoors and outdoors, and swapping the cassette isn't the easiest job to do. Double-check the cassette you have on your back wheel, count all the cogs twice and buy the same. If the cassette on your bike is 11-speed with an 11-28 ratio, you need to buy the same for your trainer. Otherwise, it simply won't work or – in the worst-case scenario, you could even damage your bike.
ROUVY tip: There is no need to focus on the weight of your cassette, so you can save some money by buying one from a cheaper groupset. E.g. If you have a Shimano Ultegra cassette, there is no difference if you buy a Shimano 105 cassette for your indoor trainer.