If that's the case, you are probably lifting in a way that is intended to bulk up, not for strength or stamina. Also, it depends on the exercises performed. As a cyclist, you want to concentrate on lower body and core, using exercises that are multijoint with a lower emphasis on upper body exercises. That doesn't mean you need to neglect you upper body because you need decent UB strength to help with sprints, and even climbing.

Work with lower weights, more reps and fewer exercises. The books that I recommended in my earlier post have some good routines for cyclists in them.