We use tires that are rated from 40-60 psi on all bikes. Customers often ask what is best for them. I like to recommend 40psi or less for heavy riders that need extra suspension. The soft tires will absorb more road oscillations, making the ride comfortable. 

Riders looking for higher speeds need to get up around 60psi. The stiffer tires will flex less, hence their momentum will push you forward. Riders that are unsure of their needs can start somewhere between 40 & 60, adjust as you see how it fits your needs.