Time Trial / Time Trialling / TT

User guide to aerolab ...
https://www.dropbox.com/s/zwbs351x4uwfj86/User%20notes%20for%20GC%20Aerolab%20V1.02.pdf?dl=0
Some results from testing at Hillingdon. Winter bib tights, winter
base layer, summer road top, Bambino, so about 0.02 slower than a club
skin suit. Open site testing on traffic free circuit. 50mm wheel
https://www.dropbox.com/s/d7a4mf09swcbb8c/2015-03-10%2050mm.png?dl=0

808

https://www.dropbox.com/s/bhpw3spb0u2whdu/2015-03-10%20808.png?dl=0
So this is how I try to optimise my position without going to the
tunnel: Start with the body position. Forget about moving the bars
to start with, it's a pain with all the cables. Move the saddle up and
down. Doesn't matter about power at this stage, just do a load of runs
at various saddle heights at a reasonable pace. Try to keep the pace
(and everything else about the bike) similar (the same) for every run.
What I do is start low, go up by 10mm each time (say seven runs over a
range of 60mm) then come back down by 5mm for the first change, and
then 10mm increments. Take the data home and see which position looks
best from a CdA point of view. If you happen to have a phone app that
tells you temperature and pressure then record that every half an
hour, otherwise find the nearest airport and use the met data from
that. Once you know what (saddle to rest) drop gives you the best
CdA number then you can start moving the saddle and bars in unison to
see what saddle height gives you the best power output. It needs to be
comfortable and enable you to keep the upper body still. Once you've
optimised the drop and height you can start into different types of
extensions, different helmets etc. And when you've optimised the
extensions and the helmet you can go round the whole saddle height
loop again (but on a tighter set of variations). This is all very
time consumming and subject to environmental variations. You can
probably get a lot more done in a tunnel in a very short space of
time, particularly the body angle stuff, if you go knowing what you
are going to test, so maybe tunnel time doesn't work out that
expensive in real terms after all. You just need to get in the queue
for a booking :-)

Aero testing advice, credit to user Nutshell on the TT forum.