Time Trial / Time Trialling / TT

Well, since you ask, 37 and fit - resting HR c. 50 (high 40s if I'm really rested and been eating & sleeping well). I wouldn't have thought that 183 was my threshold although my max is just under 200 (I think I hit 195 on the last uphill kick of this particular route - the E83)

Ah, the E83, it's one of my local courses but my least favourite due to the draggy return leg then that final climb.

The going easier bit intrigues me - I had wondered why, on the 10 mile TT when I was going at 183bpm avg I averaged 22.4mph yet if I look back 2 weeks in the training diary I did a much hillier (ok, ok, its Essex, its relative) evening training ride and covered 22.4 miles in 1hr 4mins, avg 20.8mph and avg HR 164 bpm.

Maybe aim for something in the middle - try and ride the first half at 170 then ramp it up to 175, see how you go. Club events are good for trying different strategies like this - like my club's Friday Navestock 10 that was mentioned earlier in this thread.

I'd guess that your threshold is about 175 although I'll probably get jumped on again for making assumptions.