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Parlee ESX review

30 Nov 2015

Parlee is famed for its handmade, round0tubed bikes. The ESX changes everything.

Let’s get this out of the way – the ESX is built in the Far East. It’s a step away from Parlee’s acclaimed production of traditional-looking, handcrafted custom carbon frames, created almost entirely from within the confines of its Beverly, Massachusetts facility. While the loss of the ‘Built in America’ label might be hard for devout followers to swallow, I’d bet a $10,000 pricetag for the same frame built in-house would be even more painful, so it’s easy to understand why Parlee felt the need to keep costs down by moving production out of the country. 

Having a bike built in the Far East is no indicator of poor quality, and Parlee should be commended for refusing to rest on its laurels. This was no rush job – the company spent nearly five years developing and testing the ESX before the bike made it to market last year. 

Parlee ESX top tube

Mystified that other brands appeared happy to sacrifice so much of the frame’s ride quality in search of reduced drag, company founder Bob Parlee set out to achieve something super-slick while retaining the sublime ride feel that the rest of his bikes are justifiably renowned for. Parlee himself insists, ‘We don’t design bikes just for the sake of designing bikes, but the challenge of making an aero road bike that you would also want to ride day-to-day perplexed me. I enjoy problem solving, and I’ve worked a lot in my past with fluid dynamics for racing boats, testing shapes for speed and efficiency, so it kind of became a personal quest.’ 

That boat-building mentality also came across in the wooden prototypes Bob preferred to make by hand. ‘I can work quickly, efficiently and very accurately in wood,’ he says, ‘plus I get to see the shape almost immediately and in 3D, which gives me much more appreciation for how it might perform.’

Love and hate

The standout features of this bike are those proprietary shapes, developed by Bob’s own hand, with a fluted tail on the down tube that Parlee calls ‘Recurve’. Aesthetics are a matter of personal opinion, so you can make up your own mind about whether it’s an ugly duckling or not. When I rolled up to one of my regular group rides aboard the ESX, it was obvious from the strained expressions on some of my companions’ faces (something akin to taking a bite from a sour fruit comes to mind) that the ESX divided opinion. 

Parlee ESX down tube

But to get the best aerodynamic performance from a bike sometimes means seeing past the accepted norms of what a ‘pretty’ bike should look like, and appreciating a design for what it is. Assuming it works, that is. Parlee claims the numbers from its tests in the MIT wind-tunnel prove that the ESX is right up there with the best of its competitors, but graphs and stats don’t hold much clout here. On the road is where the true test begins.

Geometry-wise, the ESX is much the same as Parlee’s Z5 SLi, a bike I’ve ridden extensively and often refer to as my benchmark, such is the hugely positive impression it has made on me. When I first climbed on board, I felt I would know what to expect from the ESX, but there were a few surprises. Some good, some not so good. 

Positional set-up was aided by what Parlee calls the Flex Fit system, essentially an aero profiled headset top cap, matched to the frame shape, that effectively means 25mm can be added to the head tube length without disrupting the aero design. It’s a neat touch that enabled me to pinpoint my ideal fit with minimal fuss, something that has not always been possible on other aero models.

Parlee ESX frame

Sitting comfortably, my first impressions were that Parlee had lived up to the hype and produced a fast frame without the associated harshness of some of its competitors. I was also feeling thoroughly spoilt by the incredible spec on the bike (hence the near-£11k price). Money literally couldn’t buy a much more exotic array of components to hang off a frame. So far, all things pointed to a very positive experience.

Game of two halves

In a straight-line charge, seated, the ESX initially impressed me by gaining high speeds easily and seemingly holding on to that pace without too much effort. The aero credentials of the Simon Smart Enve 6.7 wheelset no doubt helped to form a formidable partnership with Parlee’s proprietary frame design. But once I started to shake things up a bit, pushing the ESX through a range of different speeds and direction changes, something less desirable came to light. The front end stood firm beneath my more aggressive efforts, hunkered down and driving the ESX hard into turns, climbs and flat-out accelerations, but something felt awry at the rear. I was aware of more than just a little rub on the brake pads, despite my preferred brake set-
up being to have the pads a good distance from the rim. Surprised, I began looking into the potential causes. 

Parlee ESX review

A detailed investigation ensued, including several wheel changes, skewer changes, and eventually even an entire frame swap. In the end, despite making perceptible improvements (the biggest contribution seemingly made by changing the skewer to a basic steel Shimano option), the rear end still did not live up to my expectations for a bike in this price bracket, let alone one that bears the Parlee logo. Whatever I did, I couldn’t entirely prevent the rear brake rubbing on the rim during punchy standing efforts. 

My conclusion is the frame could indeed benefit from increasing lateral stability at the rear, and maybe that’s a consequence of it being a pretty svelte build for an aero road bike at (a claimed) 950g. But to my mind that’s not the biggest culprit. 

Positioning the rear brake under the chainstays and behind the bottom bracket is exacerbating the issue. And it’s not an issue exclusive to the ESX. Several other bikes I’ve tested have displayed the same tendency. Fundamentally I don’t believe that having the brake positioned here is a good idea. When you bear down on the pedals, out of the saddle, the resulting lateral movement of the frame or rear wheel (or both) seems to be most pronounced at this point. Had the brake not rubbed, the chances are any flex might have been less apparent. It may even have gone unnoticed. 

It’s only one issue, but for me it’s a substantial disappointment that would put me off buying any bike, let alone one with a five-figure pricetag. If I were paying that kind of money, I would expect perfection. 


Parlee ESX
Frame Parlee ESX
Groupset Shimano Dura Ace Di2 9070
Bars ENVE SES carbon
Stem ENVE carbon
Seatpost Parlee
Wheels ENVE 6.7 clincher
£4,000 (frameset)

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