Originally Posted by TejanoTrackie

I disagree with the text that I’ve placed in bold. Head tube angle works in concert with fork offset (rake) to attain a certain amount of trail for different performance characteristics. Racing bikes require quicker steering than touring bikes, while still being stable at high speeds. As to my statement that head tube angle affects the shock absorbing qualities of forks, this is not a “belief”, but rather physical mechanics that can be quantified. The force that the wheel applies to the fork can be broken into two components as follows:

Axial component = Vertical force x SIN (head tube angle)
Transverse (perpendicular) component = Vertical force x COSINE (head tube angle)

As the head tube angle becomes slacker (smaller), the axial component of force becomes lower and the transverse component becomes higher. The axial stiffness of a fork leg is much higher than its flexural (bending) stiffness, such that axial shock force is transmitted with almost no attenuation, whereas transverse force is reduced far more as the fork flexes in bending.