Originally Posted by dirtyphotons
most triathlons are not the ironman. sprint distance is 20km on the bike, olymic is 40 km and ITU long distance is 80 km. all much shorter than road races.
tri bikes are also set up to put the rider in a very aero (usually uncomfortable) position. reasons for this include (relatively) short distances, energy conservation for other legs, and the fact that in most amateur tris you're not allowed to draft and work as a team against the wind.
Unless they've changed the regulations drastically since I raced, ITU regs are that there is no drafting. Back then, the 2 minute penalty could be dealt with in 2 ways:
1 - course judge took your race number and reported it to the timekeepers, who tacked 2 minutes onto your finish time.
2 - course judge could pull you for a 2 minute roadside, which meant losing momentum and standing around for 2 minutes twiddling your thumbs and watching people rip past you.
The steep ST angle on tri bikes not only puts you in a very aero position, but also puts you forward over the pedals more, prepping your legs for the run stage of the race.