[Closed] Does FTP change much over a year?

That would be threshold rather than FTP buy there's no harm retesting.

Ok.

I was looking at this calculator

http://www.britishcycling.org.uk/membership/article/20120925-Power-Calculator-0

But in answer to my question. Would you expect it to move much from on season to off season

Average hr is, to be fair for the most part meaningless.

Best do a 20 mins test on trainer road or similar.

I did a couple of hard rides in the welsh trail centres last June, and my average HR was 169 for 1hr 10 mins

i don't think you can infer FTP from this.

tarmac or turbo/ rollers are better to estimate threshold power/ HR

I'm not sure there's sufficient information to give an answer. The amount it will vary will depend on both the amount of training you do, the amount you'd done in the previous say decade, and the difference in intensity between your on and off season.
This simplest answer is go out a do an hour as hard as possible (so preferably on a road route where you don't have to slow down) with a HR monitor and use that value.

If you do roughly the same amount of training and same weight I'd expect to stay about the same +\- 2bpm in my case. People with power meters say measuring by hr is pointless but I've found it pretty reliable for the last 3 years, along with an annual lab test. Mines 178 for 20min tt pace. I did find my interval hr moved from 189 to 195 in a season though.

I get my threshold heart rate from a race rather than a turbo. You will have a maximum, which you may know (mine's 191). That isn't likely to change. What will change with fitness is you ability to sustain values not too far from this for a given duration.

BC uses 20 minute threshold. And I'd say an average of 169, provided it didn't go down too low, is a pretty reasonable estimate. A long off road climb in Wales would give you a 20 minute threshold. I'd say 170 is ok.

That means that you will want to train at about 160bpm for "sweet spot".

I calibrated my heartrate zones to my power meter and ftp. So my threshold on that site is 168 and my level 4 starts at 155. That's made for some pretty hard commuting, but eventually I expect this threshold to go up. 170 is the next objective, and i'll test that in a Club 10 TT.

You can't really infer a lactate threshold heart rate from a couple of hard rides. Do a proper test like the British Cycling one. What I find is that my threshold heart rate stays the same but the power I generate at that HR can vary by 20% between being detrained in mid winter and properly trained in spring/summer. HR is better than nothing but its much more useful when used with power measurement.

With regards to the BC test, I did a lab test 2 years ago and came away with a AT of 163. The 169 rate I averaged for over 1hr was just a recreational ride at Cwmcarn. The reason I think I was able to ride so hard was the fact that on the ride I was feeling rather competitive and was pushing as hard as possible to not get caught by a rider who was about 100m away on the climb.

So, if I do go and do the test again, can I just ride a 3 mile hill climb as hard as I can go using the figures I have to hand to give me an idea on what hr to pace at?

Dunno about the bc test you are referring to, but the idea is to go as hard as you can and only just finish. Might take a few goes over a few weeks to get right, and I'd say unless it's in a race or you are really really motivated it's likely to be slightly lower than what you can really do.

Agree with the comment above, basically my equivilant hr to my "ftp" stays the same, but I get faster (therefore power increases) during the season. That's why it is useful for pacing, but not so much for measuring training progress.

Things like sleep, alchol, illness, caffeine can all affect you hr. I did one Garrick averaging over 190 which was a freak result.