Well worth buying this game on sale now that Ride 5 is available.
Note that this game is quite difficult and unless you are naturally skilled you may find the career progression tests frustrating.
Looking at the steam achievements my guess is that at least 75% of players quit the game in under four hours of play, never to return.
Leaving the career aside there are a tonne of bikes and tracks that you can have fun with doing single races against the AI or just running time trials.
Overall good game.

this racing game is very fun, only small cc motorbikes are not better than ride 5

Ride 4 is a solid motorcycle racing game with realistic driving physics. There are also so many cool dlcs you can get to make the game even more fun right off the bat. Not to mention the unique game modes included. 9/10 game