My LTHR is 165 bpm.

When I run, farther than I can sprint, the fastest I can go is 163 to 165 bpm and whatever pace that gets me. I'm burning matches when I go over my threshold, and need to slow down to recover. I can hit a steady state if I stay just under my threshold. (I ran a pretty flat 10k this summer, it took an hour, my average HR was 162 bpm.)

I don't know what my max HR is with any real certainty. Knowing it wouldn't have any tangible benefit, like allowing me to run faster.

This doesn't work on the bike, though. Running is pretty simple, cycling is more dynamic. I can burn a match going up a hill and recover on the way down, the fastest way through a ride depends on smarts and strategy, not just output.