The Triathlon calculator (http://triathloncalculator.com/) works well for me, except the bike. It predicts an IM speed of 15mph (based on 22mph TTpace). I did 18mph (IM Lou). I do not think I over did the bike, my run split was a couple minutes slower than expected and I could not imagine going any easier on the bike than I did. Does this indicate I am not pushing hard enough on the bike for the shorter rides? Should my 20min TT speed be faster?
If it helps, in OLYs I have done 19.2 (Edinboro) and 20mph (Pittsburgh Tri) and in HIMs 18 (Spirit of Morgantown) and 18.4mph (Racing for Recovery). I have a hard judging effort on the bike. Going just a little faster “feels” like it is going to be too fast for me to maintain for any substantial period of time. What is the best way to address this? I have considered saving up and getting a powertap to keep myself honest.