All New Parlee ESX Aero Road Bike

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?

All New Parlee ESX Aero Road Bike

“The challenge was creating the tube shapes and profiles that delivered both aerodynamics and the ride feel that Parlee’s known for,” he said. “And there’s backlash against the aesthetics of some aero road bikes, so we wanted it to look good, too.”

They also had to think about weight. Some prototypes were actually as low as 800g, but production models ended up a bit heavier because they said “they were just way more fun to ride.”

“We did this with a design we call Recurve, and it’s patent pending,” Rodi said. “The shape is a modified air foil with a rounded front with a reversed curve on the trailing edge that comes back on itself. What’s striking about the design is that it’s obviously aero, but not so deep.

“It delivers the promise of the Kammtail’s aerodynamics but with the torsional stiffness and ride quality of a traditional round tube. We wanted a bike that just plain worked and wasn’t in any way a nuisance to own.”

As proof of that, they decided on using Shimano’s direct mount (two bolt) brakes rather than the hidden TRP direct pull calipers. The latter may have been a bit more aero, but the Shimano’s are much more user friendly. And they’re looking forward to trying the upcoming dual-bolt eeBrakes (spotted on one of Fair Wheels’ show bikes) on them, too. On top of that, the cabling is all fairly straightforward and easy to service.

All New Parlee ESX Aero Road Bike

With their Z5 road bike, they offer standard and tall frame sizes, creating 24 effective frame sizes. The ESX uses a variation of this flex fit geometry: There’s a top cap that nestles into the frame, around the steerer tube, that allows the frame to appear taller and reduce the number of spacers required to fit taller riders. They’ll offer five different frame sizes. The bonus: Their system still allows you to run any stem you want. The pic above shows it without, and below with the spacer.

All New Parlee ESX Aero Road Bike

All New Parlee ESX Aero Road Bike

The seatpost is proprietary, available in 0mm and 25mm offset. It carries the Recurve aero tube shape from the seat tube all the way up to the saddle. The clamp bolt is flush with the top tube.

All New Parlee ESX Aero Road Bike

About the aerodynamics, they’re still determining what they’ll publish. In reality, wind tunnel tests are funny things. Brands can find the angle and speed and other settings where they perform best and use those to tout the product. Some of it’s useful, but in the end, Parlee seems content that their tests validated the concept.

Beyond the unique looks, the frames are light. With a 925g to 950g target weight for a M/L size, that’s only about 100g heavier than their Z5 and very, very light for an aero bike. Their custom fork is about 320g with 300mm uncut steerer. Seatpost is around 185g.

All New Parlee ESX Aero Road Bike

Other quick specs: The bike runs full internal cable/wiring and is electronic/mechanical ready. Tire clearance is good for up to 28c, and it uses a PFBB30 bottom bracket.

Bikes start at $6,500 complete w/ an Ultegra mechanical build. Frameset is $5,400 w/ seatpost, Cane Creek HS and fork. They’ll top out at $10,200 with full Dura-Ace Di2 9070. Enve Composites bars, stems and SES wheel sets are available as upgrades, as are the new Mavic CC40’s and the EE Cycleworks Direct Mount brakes. The base spec of all the complete ESX’s in the US is 3T Team Stealth Bar and Stem, HED Ardennes+ Lt Wheels and corresponding (full groupsets) i.e. Ultegra Di2 builds get full Ultegra parts including chains and cassettes.

It’ll come in their usual matte blacks and will be offered through their custom paint program, too. Rodi says the extra real estate on the aero tubes is already letting them do some pretty sweet custom paint schemes that just wouldn’t look right on round tubes.


2014 Parlee TTiR triathlon bike

While the TT bike got a minor update last summer to make it Di2 compatible, it sees a bigger revamp for 2014. The core design remains true, so it’s more of a mid-life freshening up. The “R” designation in the name hints at what the changes are meant to accomplish: Make it more of an all-out race machine.

2014 Parlee TTiR triathlon bike

It now uses the Shimano Direct Mount brake (for the rear) and a full carbon press fit bottom bracket shell. That opens the bike up for easier cable and wire routing around the BB. The chainstays use the ESX’s design and are stiffer and stronger for better power transfer than the 2013 TTi.

2014 Parlee TTiR triathlon bike

The dropouts become standard vertical dropouts (no more rear entry sliding dropouts) and it gets a replaceable derailleur hanger. It eliminates the ability to really slam your rear wheel into the aero tuck behind the seat tube, but it’ll make service much easier. And, Rodi says it keeps the cassette placed within Shimano and Campy’s minimum chainstay specs, so shifting performance will be what it’s supposed to be…particularly important for the new 11-speed groups. They also opened it up a bit to accommodate the growing width of aero wheels – the rear end will now fit up to 27c tires.

2014 Parlee TTiR triathlon bike

The icing on the cake? The frame’s about 40-50g lighter than the 2013 TTi. Complete bikes start at $4,200 (Ultegra) and they’ll start shipping around Christmas.


  1. Culpritbicycles on

    Parlee, Well done, really a beautiful bike with remarkable weights. Hats off to you. You guys are a great example of the little guys fighting against the Big boys, in the same fight as Culprit. Keep up the innovation.

  2. Tom on

    nice looking bike, but I’m not buying the fluted tail business. It add section stiffness fore&aft, but does not contribute to torsional stiffness in an efficient way. A Kam tail section is more efficient in that regard. Maybe it was done for looks.

  3. Eyal on

    Stunning bike! But too heavy. Bicycle manufactures of this caliper should be pushing weights down significantly. Unfortunately, they’d have to license many high end composite patents which would make these bike too pricey.

  4. RAB share on

    Scott Foil HMF (low-mod) is around 950g for the frame, and it sure doesn’t cost $5400. The high-mod HMX frame is in the 850 range and that bike has been around for a few years. Maybe this bike is more aero, stiffer, whatever, but they aren’t breaking new ground in the weight department.

  5. Wiley on

    Oh no, a bike with a lifetime warranty, aero properties, and rides awesome is 950g in a 55cm? Heavens to Betsy! I think the real issue here is that these bikes come with brakes, which only slow the bike down and make it super dangerous! This bike wasn’t meant to break the mold with weight, so get over it. A 14.5lb complete, oh no.

  6. Chachar on

    “It delivers the promise of the Kammtail’s aerodynamics but with the torsional stiffness and ride quality of a traditional round tube.”

    This is a really stupid statement. Kammtail’s advantage is its stiffness over a more traditional, non-truncated airfoil. The “fluted” tail on the back would probably have a negative impact on aerodynamics (the concave sections is begging to have pressure build up) with no benefit to stiffness. They are basically getting a sort-of-aero shape (compromised airfoil) without the stiffness or weight advantages of a kammtail.

    The TT bike looks like a P2 with hidden brakes. Could be a very fast bike (P2 is), but certainly nothing new.

  7. Ditto on

    I am disappointed with the direct mount rear brake. Service on madone’s (5+ series) sporting the same is just tedious at best, and terrible at worst.
    I suppose it makes sense for the aero aspect, but at some point I would like to see the drag difference between the two mounting locations with a rider mounted and pedaling.

  8. Ditto on

    @ RAB share – unsure where you are getting those numbers, but most reviews peg the 2013 Foil HMX NET frameset (56 cm, roughly same size as the Parlee reviewed here) at 1050g.

    Don’t get me wrong, the Foil is a nice race bike… Mine took a beating in the local flat crit scene. That said, it is a race bike and I tried to ride it as little as possible due to the position and road-chatter that the front end (and wheelset, admittedly) didn’t deal with very well.

    Yea, the Foil costs less. Parlee occupies a niche filled with high disposable income people who value/lust for a great performance ride.

  9. RAB share on

    830 for the HMX version, 980 for HMF. Peloton’s initial review of t the HMX also claimed sub-900 weight.

    I’m sure the Parlee is a great bike and wasn’t trying to directly compare the two. Just using the Foil to point out that the weight of the Parlee, in and of itself, is nothing special.

  10. wiley on

    @RAB share

    Waah. You’re right, congrats. Again, the ESX wasn’t built so shatter weight records. They had samples that were around 800g, but the ride quality wasn’t what they wanted.

  11. rico on

    Pretty cool to see what they came up with. The whole aero movement provides some interesting room for builders to experiment, racers to test and the whole lot to debate. Like Ditto said he uses the foil for crit racing, these things have atheir place in racing and in boutique sales. I personally stick with a light all rounder, but these things are getting closer to ideal all the time.

    Imo, it’s cool to see what Parlee, some real pros, came up with. I also appreciate all of the comments and ideas random people add to the mix. Onward and upward.

  12. colorado chris on

    I’m lovin the bigger tire sizes on that aero road bike. I can only run 23cc in back. I much rather run 25’s or even 28’s which would be awesome. Now if they only make them with a 54cm TT rather than the longer 54.5 in my size. I also like the idea of not going for the lightest weight. I want something I can ride with confidence and rides smooth. How will the aero bike ride compared to the Z5?? I love that bike.

  13. Ellis on

    Sorry Chachar, but its not a silly statement. The point of using a Kammtail profile is nothing to do with stiffness, but getting the best aero performance whilst keeping within the UCI’s 3:1 rules. A Kammtail section behaves almost as well as a full aerofoil section, but is UCI legal. What Parlee are saying is that their profile does the job of a Kammtail without compromising stiffness

  14. Ditto on

    @ RAB share – Mismatch of frame sizes in the link you provided for frame weights. Try again.

    Jared – good on you folks for making room for larger tires. Aero doesn’t mean track-frame.

  15. Jim on

    I find some of the criticisms rather laughable. Comparing a Parlee to a Scott is apples and oranges. Why is the Parlee more expensive? Ride one sometime, and compare the ride qualities, and you will understand. As for disk brakes, they are heavier and less aerodynamic. Weight? As the article says, they could have made it an 800 gram frame, but it would not have had the ride quality of a Parlee. In my job as a bike shop service manager, I have ridden many ultra light bikes, and they ride like a bag of rocks. Parlees have an unbeatable ride quality, and that quality adds a little weight. Worrying about 150 grams? Skip lunch.

  16. Kevin lincoln on

    Can you use a large water bottle? The pictures have a small bottle. This might sound picky, but living in Texas and riding when temps reach the 90s, you want a big water bottle. Does any one know the answer to this? Thanks!

  17. Cooper Allen on

    This is such a nice looking bike! I love how sleek it is, and how lightweight. This would be perfect for a race, or even a triathlon. It looks so durable, and has such a unique look.


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