Carry on testing

Well, further to previous posts, we continue to compare frames, wheels, tri-bars etc. Last Wednesday Ed was over and as it was the club's noon-aero night we decided to do a track bike 2-up. Over the years we've done quite a few of these and it was a good opportunity to do a further try-out on our regular course. The results, however, are a little out of odds with what I had calculated we would do.
In previous years, I've ridden this machine in this set up (apart from the wheels with the addition of a Mavic Elipse rear wheel instead of the usual XP33 on Miche -32 spokes crossing 2) and in 2007 recorded times as follows:
May - 27:38
June - 28:01
July 26:14
August - 26:56
In May on my TT bike I was 2 minutes faster the week before and the week after.
In June, the difference was almost exactly 3 minutes although in July it was down to just under one minute and in August back to about 2 and a bit minutes. On all of these occasions, the TT time differences were consistent on the weeks either side of the track bike outings.
So what happened this time? well, firstly the time difference is to be measured in seconds being plum in the middle of the times recorded on this course under all conditions although interestingly we felt the 2-up was going well until Ed pulled his wheel over with about 3 3/4 miles to go. At this point we had been slowly catching another rider, but after slowing and getting going again I got further behind them over the final distance.
I guess my point here is that:
a) A 2-up with matched riders used to doing TTT's is definitely faster than an ITT.
b) Fancy equipment matters far less than fitness. (Although having all of the bells and whistles makes you feel fast)
c) What's going on in your head and the state of the wind are also key deciders.
Perhaps the only way to find out is to do tests in either a wind tunnel or an indoor velodrome. Both of these are scarily expensive, so perhaps that will have to wait.
By the way, the pic shows Phil Griffiths & Eddie Atkins 2-upping in the rain some years ago (Courtesey Bernard Thompson).