bandrew,

I have a few suggestions for you to try:

1) If you aren't already stretching your quads before AND after the ride, then please start. (In a standing stretch, make sure your knees remain together - no cheating)

2) Think about raising your seat to take the quads out of their inner range (which can easily lead to nasty cramps)

3) Try a magnesium supplement to combat cramps

4) Get a good, solid sports massage to loosen the muscles

5) You might be looking at a psoas (hip flexor) injury, which can be confused as quads pain. This muscle attaches proximally to the lumbar spine, so lower back posture can be a factor. A physio can assess and treat if need be.

Please let me know how you're getting along.