First post. Be kind :)

I do not have the benefit of training with power yet (just can't stretch that far money wise), but I am trying to train using HR zones. A few weeks back I followed the Friel method of finding my cycling LTHR with a 30 minute TT effort on the bike. I then followed his instructions on setting my training zones. However, since then I have read a number of slightly different variations on calculating my training zones from my LTHR. The biggest discrepancy between the Friel method and others that I have seen is that others calculate LTHR as 95% of the average HR from the TT test. However, the Friel method does not do this. It just calculates the training zones from straight from my average HR from the TT test. As you can imagine, there is quite a difference in training zones from both methods. For example, what would be Z2 for the Friel method turns out to be Z3 for the others.

Which is correct? Is there a right answers? What do others who use HR training zones do? What method do you use?

Thanks in advance for any replies.