Originally Posted by
c_m_shooter
https://www.youtube.com/watch?v=P6b9RxXGzSY
It depends on what you expect. The simpler the bike the more likely it will be ok. I would avoid anything with suspension and a front derailer. Rear gears may be okay if you check the setup before you ride. Park tools has videos on how to do everything.
Why are you afraid of front derailleurs? Having more than one chainring really helps balance gear range & spacing, without the need for thinner, weaker cogs at the rear.