What you're reading today is the intro to a series of installments matching you to your optimal tri bike. I'll describe the "you" I'm writing about in each installment and then help you narrow your choice of bikes. This is similar to the process I go through during a fit session, like the sessions which occurred over the course of Slowtwitch Road Shows.

My idea of a proper, complete, satisfying fit session is one that replicates during a session what you see, feel and experience out on the road; and then prescribes the bikes that will precisely fit, and that will handle well. Your long or short torso; your fore/aft posture aboard the bike (forward or less so); riding lower in front or less so; all inform the bike that is ideal for you.

There is a conundrum in tri bike fit however. Road and tri bikes makers have changed their approach to geometries. Road bike makers who used to make one road geometry now almost without exception make two or three: so-called gran fondo geometry; middling road geometry; and perhaps a more aggressive road or criterium geometry. You want a road bike? The road bike world is your geometric oyster.

Triathlon, not so much. Here's a data point for you. Felt's IA in size 56, Quintana Roo's PR5/6 in size 54, Cervelo's P2/3/5 in size 56, Dimond's size M and Trek's Speed Concept in size L are virtually identical geometrically. They are all roughly built with a stack of 540mm and a reach of 425mm. This is Trek's geometry, that is Trek is the company that first chose this geometry for its Speed Concept in 2011. You can see in the chart above how certain bikes coalesce around this geometry in size M and L, and as you can see you can throw Argon 18 and Orbea into this mix.