There are two chain rings.

This is so neat. We rode this morning. Although there were some hills, the trail was flatter than the ones I normally ride. WOW! I really increased my MPH! The trouble is, I love the challenge of the hills which of course lowers my MPH. I want to see if I can get up them while increasing my speeds. I do plan to ride one of the long flat trails and see what happens.

There are two hills that I look at and immediately get off my bike and walk. The seem to be at 90 degree angle and are very short. It takes a lot of stamina just for me to walk up them. I have tried to climb them periodically with no success. I have seen the really good riders struggle to get up them. And they are clipless and have really light expensive carbon bicycles. .