By Coach AJ D3Multisport.com
What is a triathlon bike? How is it different from a road bike?
In summary from the video, a triathlon bike has a steeper angle for the seat-tube which makes it more vertical thus allowing to get your hips and body more forward in the aero-position compared to road bikes. Triathlon bikes are made for 'aerobars' instead of the curved bars that one sees on road bikes.
Triathlon bikes are more suited to courses that don't have a lot of climbing and steep grades. They are very responsive in the aero position so pack riding in the aerobars can be more dangerous and is often a 'no no' in group rides. They are built for speed and the ability to get your body into the lowest profile against the wind.
Many beginners and intermediate triathletes have good road bikes that they can use to train on. You can purchase clip-on aerobars to get you into that aero position to save you some money. Though you will have to get re-fitted to the aero position and you may need your seat, stem, handlebars and other things moved to get you as comfortable as you can. If you love triathlons and want to improve the most, having a triathlon bike will allow you to get into the best body geometry for the best performance. Putting aerobars on a road bike will give you a good approximation to get started.
As with a triathlon bike or a road bike, proper fit is imperative to prevent discomfort, especially during longer triathlons. Proper fit can significantly improve your performance on the bike by allowing you to get the most efficient power output transferred from your legs to the pedals.