As far as I know they don't have auto LTHR detection for cycling. And apparently your running LTHR isn't necessarily the same as your cycling LTHR. I had a hard time accepting that for a while, I thought it should be the same for anything I do, it's the point where my body stops being able to process lactate quickly enough; because you use different muscle groups for different sports, you have different oxygen needs running and cycling, and different levels of LT production.

Anyway, this was a tangent. Max HR is really difficult to find, it's highly individual but doesn't really tell us anything important about a person's biology. Just doesn't make sense for HR zones. LT is easier to find, and very meaningful for exercise purposes. I agree, LTHR is ideal for zones.