As you'll notice (and be told) those age adjusted hear rate charts are not accurate. Particularly if you cycle (or run) more than average. Using your own data is the best way to set your own zones. Google an article at Training Peaks from Joe Friel on setting HR Zones (I'm unable to post links) and it will show you how to set your LTHR (Lactate Threshold Heart Rate) using a 30 minute test.
Using your LTHR is probably the best way to set your zones as your likely not going to be able to find your actual "Max" HR.
If you're not keen to do Friel's "test" then look at your own data and find the hardest 30 minute effort you've put in on the bike. The average HR for that 30 minute (or more) effort would be a good proximation for LTHR that you could plug into a calculator and get your own HR zones. If you don't want to fuss with Friel's zones, just get your LTHR number and use the cycling HR calculator at 2Peak dot com.
And you'll have a pretty good idea of your zones. This all might be overkill, or it could be a good way to measure your self and your riding.