tri or road bike
why wasn`t brownlee on a tribike in photo of sydney race last issue ?
Tri, or TT bikes are only suitable for non drafting / timetrialling.
The elites race in draft legal races - ie like a road race, so use a road bike.
You can see the same thing in the grand tours - road bike for normal stages, TT bikes for TTs.
You need the agility of a road bike when racing in a pack, both for performance and safety reasons.
Ironman races do not allow drafting, so you will see TT bikes used in those.
TT bikes are usually banned from sportives for the health and safety reasons.
A good reason to have 2 bikes then......