Everybody’s talking about Pad X and Y, or Pad Stack and Reach, in regard to bike fit and selection. What is it? How do you measure it? How is it used?

There is hope for Aliens, and by these I mean the freaks of nature who contort into pretzels to ride long and low positions. Aliens, here are your tri bikes.

We routinely see wind tunnel data through a “sweep,” that is, from a positive to negative yaw. But what yaws do we actually see in the real world of racing?

A Pad Y/X of 630mm/505mm is a typical position for somebody between 6’0″ and 6’3″ who rides pretty steep, with a fair bit of armrest elevation drop from the saddle.

Top tri brands make tri bikes that fit marvelously. Today’s tri bikes are very good, but they’re very uniform, and the lack of variant geometries leaves many riders out.

The first in a series, prescribing bikes to match the profiles of various kinds of riders. The rider here is 5’9″, rides pretty steep, pretty aggressive. What’s his bike?

Frame metrics are real, they matter, they tell the truth – stack and reach tell the truth – but they don’t tell the entire truth about fit.

First published 16 years ago, this article by John Cobb on wheel (steering) torque is even more topical today, with the increased use of deep wheels since its first publication.

Steering torque and center-of-gravity have become competing imperatives in bike geometry, with front-center caught in the middle. What’s caused this tension? Deep front wheels.

What you’re reading today is the intro to a series of installments matching you to your optimal tri bike. I’ll identify you, and then “prescribe” the bike(s) that work best.

American Alexey Vermeulen of the Team Lotto NL Jumbo squad finished third at the 2016 US Pro National TT Championships on this Bianchi Aquila CV.

Taylor Phinney and Carmen Small are the 2016 USA Cycling professional TT champions and here are images from the event near Winston-Salem, NC.