The Parlee ESX aero road bike is a completely new model, and Bikerumor’s one of very few entities who have seen the bike in development. Check our factory tour for a look at a very early prototype. It’s been refined quite a bit since then, coming together as one of the best looking (and lightest!) aero road frames we’ve seen yet.
“We’re certainly not claiming to invent the category, but aero road bikes are certainly growing as a segment,” operations manager Tom Rodi told us. “Aero and weight are always a priority. We knew we could make a fast bike because of our triathlon bike, but we wanted to see if we can make something for the road and in the weight class we’re known for.”
Throughout the project, even back when we saw the prototypes, they’ve been testing in the wind tunnel. First, they put it against their own round tube Z5 to see if there was enough difference to justify the effort. They had some help from folks at MIT to interpret the data, and the answer was yes, based on drag and watt savings. For example, at a 10º wind angle at a realistically fast output, they found about a 13 watt savings. The savings were validated across a range of angles and speeds that reflected what normal riders achieve, so they moved forward.
Rodi says there’s always some compromise when developing an aero road bike. The question is, what are you willing to give up? A bit of torsional stiffness to get more aero? Or a slightly less deep tube profile for enhanced comfort?
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