Chain driven indoor cycling bikes are essentially an outdoor stationary bike that you use indoors. The chain more or less resembles that of the outdoor bike.
As you know with outdoor bikes, every now and again they will require some TLC. With the chain constantly rolling over the sprocket and pressure used to spin the flywheel, it can start to wear.
From time to time, you will have to lubricate and tighten the chain to make sure it is in perfect working order. It’s very simple task but will allow years of use out of your indoor cycling bike.
An indoor cycling bike that is belt driven requires very little maintenance as the belt itself is very strong and is only rolling over soft curved edges to generate the power to the bike so very little damage is done, if even.
In a very rare circumstance that a belt drive was to snap, you can try fix it yourself or may have to take it to a local bike mechanic to fix it which may be costly.
But once again, very rare.