Looking for a bike for my 12 year old son. Something he can use to try out different disciplines – probably Mountain and Cross initially. Thinking about some sort of crossover – front suspension with flat bars maybe? He’s 4′ 11″ish. Currently rides a 26″ kids mountain bike (no suspension). Its heavy, poor gearing / shifting (Shimano RevoShift), and crap breaks. Any recommendations? I’m open to new or used, but not looking to break the bank as it’ll be something he probably outgrows.