I've found that both running and riding tighten my hamstrings making me more prone to hamstring injuries during other sports unless I stretch.

I typically don't stretch before or after rides but I do stretch at other times. I will stretch after a brief warm-up before a more intense or longer ride. If I don't I can have problems with my calves.

Note: I'm almost 48 and I was less concerned about this stuff when I was younger.