Aero road bikes have become so important that even the smaller manufacturers of bespoke carbon bikes have felt the need to join the ‘faster for free’ bunch. Parlee is leading the charge with its latest model, the ESX.


The reason Parlee has taken a while to join the aero road category is, in the firm’s own words, “ride quality gets sacrificed [for aerodynamics]“. That’s a sentiment we certainly agree with based on our experience. Many aero bikes have had to compromise ride feel and comfort to be fast. Now, though, Parlee claims it has figured out how to deliver aero without compromising ride quality – so we were keen to take a closer look at the ESX.



Parlee also claims to have built its name on making bikes that have a superior ride. We can’t argue with that. The firm wasn’t prepared to sacrifice ride quality in creating the ESX, and the new frameset took Bob Parlee more than five years to create.







Before Bob got into creating racing bikes, he designed and built racing boats, so we’re assured that he knows a thing or two about fluid dynamics. His experience has had a significant influence on the ESX frame.



Transferring skills from boat to bike building is not straightforward; different tube shapes need to be blended together to cope with the constantly altering aerodynamic profiles. To satisfy these demands, Bob came up with a patented tube technology that he calls ‘Recurve’. Basically it’s a fluted tail and its appearance is most obvious in the seatpost.

Clean air

It is claimed this design meets the demand for clean airflow and offers just the right level of stiffness to resist the twisting forces exerted when a rider pulls on the bars, pushes on the pedals and bears down on the frame.







As with all Parlee models, weight was a key consideration. However good the ride, and no matter how efficient the aero shape, the company was not going to sign off on a 2kg frame. Hence, a sizeable amount of development time went into making sure the ESX was acceptably light. Parlee lists the weight of the frame as sub-950g.



Parlee obviously kept an eye on its existing customer base, as it has given the ESX enough clearance to run 25c or even 28c tyres. With pros using wider tyres to reduce rolling resistance, this may be a wise move ensuring that, in this regard, the frame is future-proofed.

Cutting-edge tech

In keeping with that forward-thinking ethos, the ESX is compatible with either mechanical or electronic shifting formats. A great deal of thought has gone into the practicalities as well as performance. The cables are well hidden but without making the frame a complete nightmare for a mechanic to work on. It has also been fitted with a Pressfit 30 bottom bracket option.







The sleek technical solutions don’t end there; Parlee has integrated a Flex-Fit system for the frame. Whereas previous models of the Z series offered two lengths of head tube to accommodate two levels of flexibility, the ESX has the same adaptability built into the top cap of the headset.



In the lower stack version, each of the five basic sizes has a one-centimetre finisher. On the bigger frames with longer head tubes, the spacer adds 26mm to the height of the front end, flowing into the top tube bulge in what is arguably a much sleeker design.



Parlee has also opted for Shimano’s direct mount rear brake and has tucked it on the chainstays behind the BB. The seatpost uses Recurve tech to give an aero profile, in two layback sizes, zero or 25mm, and is able to accommodate internal batteries for electronic shifting systems.







The first ESX frames – the mid sizes of the five – will be available in December. You’ll have to wait until the start of next year for the smallest and largest sizes. The recommended retail price for this Asian-manufactured frame is £3,999, which, as you’d expect, includes the fork and seatpost. Contact: www.parleecycles.com

The only way is esx… what’s in a name?

When we asked Bob Parlee about the name of the ESX, we were more than a little surprised by his answer.

In short, ESX stands for Essex, sadly not the UK county to the north-east of London, but Essex County in Massachusetts – this one, north-east of Boston, where Parlee is based. Essex is typically quite windy and is a very popular area for sailing – it’s also where Bob grew up. Being such a sparsely populated area, as well as windy and flat, the roads of Essex County breed a certain type of rider.



It was here that Bob did a lot of testing on the new frame, and while the ESX name was originally a bit of a company in-joke, it evidently stuck.



This article was first published in the November 7 issue of Cycling Weekly. Read Cycling Weekly magazine on the day of release where ever you are in the world International digital edition, UK digital edition. And if you like us, rate us!