I've done the lake trail 48 times over the past 3 years and I have a tendency to push it fairly hard nearly every time. So a 37 second improvement over a short time, even this year seems like quite a bit. I really beat myself up going for a PR just maybe 3 weeks prior on my Specialized and while I got the PR that time, I just shattered it easily with my Trek. Nearly same wind direction and speed those days too.