Tri bikes are a cross between a road bike and a TT bike. Look at the tubing, some of it is typical of a road bike, and some is like that of a TT bike. Tri bikes are used in...well Triathalons. The bike portion is usually a little over 100miles which is too long for a full blow TT bike. There is no drafting allowed in Tri's either as in Time Trials, this is why some of the bike focuses on aerodynamics while others are on lightness. Hope this helps.