Whats the relationship between handlebar rise and head tube angle in mountain bikes, and how do I choose the right rise to complement my bikes geometry without compromising handling and control. It seems like a lot of riders just slap on a handlebar without considering the implications of the rise on the head tube angle, and its not uncommon to see bikes with a mismatched setup that affects the overall ride quality. What are the general guidelines for choosing the right handlebar rise for different head tube angles and travel lengths, and how do factors like stem length and saddle height play into this equation. How important is it to consider the riders body position and preferences when choosing a handlebar, and are there any general rules of thumb for determining the optimal handlebar rise for a given rider and bike setup.