Chapter2 Koko review: Striking in both performance and aesthetics

The Koko is Chapter2's updated aero road bike, taking much of the design from the Kiwi brand's previous best aero road bike, the Rere, and improves aerodynamics though with new tube shapes, increased stiffness, larger tyres and features a flippable seat clamp that allows riders to choose the level of compliance. 

Chapter2 is a New Zealand based frame manufacturer that produces a number of boutique road and gravel bikes for performance-oriented riders. Prior to Chapter2's existence, New Zealander Neil Pryde started out working with the wind to develop windsurf and yachting sails, then his son Mike Pryde started working against the wind, taking the lead at Neil Pryde Bikes. In 2017, the latter was rebranded into Chapter2 - a literal second chapter of the family's bike business. 

The New Zealand and Maori roots and themes run deep through Chapter2, channelling inspiration from the approaches and traditions of the native people and carrying out product performance testing at facilities like Auckland University’s Wind Tunnel in order to create the best road bikes possible, while retaining a boutique feel to each of its frames.

Chapter2’s naming convention uses Maori language that reflects the elements and theme of each product. Koko means “to soar, fly” in Maori, so Chapter2 must be pretty confident the new bike is going to be quick on the road. 

Image 1 of 6

Design and aesthetics

At first glance, the frame shape is striking, the purposeful stance immediately underpins the frame's aerodynamic aspirations. The downtube bends around the significantly tucked rear wheel, and dropped seat stays form a tight rear end to reduce surface area (and drag). The low-slung top tube follows the same design criteria keeping the front triangle size compact for a better aero profile.

The downtube is subtly scooped around the front wheel to better deliver the air from the front wheel and around the Koko’s new kammtail downtube, which matches the kammtail seat tube continued from the Rere. The fork crown extends back into the downtube to further smooth the shape for passing air from the rim's leading edge. The headtube also gets some additional moulding across the top to smoothly lead into the tapering top tube. The seat stay and seat tube junction’s shape is almost winged in the way it widens before extending around the rear wheel.

Chapter2 has managed to navigate the integration of these features while still keeping the Koko UCI Approved.

Image 1 of 5

Chapter2 has designed this kammtail shape not only for aerodynamics but to deal with lateral stiffness loads, too. The switch from the Rere’s aerofoil downtube to a new truncated kammtail tube profile has achieved a claimed stiffness boost of 13.35% around the bottom bracket and 35.64% around the headtube for a more direct ride feel.

Comfort has also been added. Not only has Chapter2 spread the frame to fit a 32mm tire, but there is also a flip-able seat clamp which offers two levels of compliance. In the normal position, Chapter2 still promises a comfortable ride, however, the clamp can be flipped to add an extra 8.5% more deflection if you are seeking even more comfort.

Chapter2’s colour options are all limited edition so when they are gone they are gone. The Essential Collection Gloss Black option we feature here has Maori design and Torquise details across the frame. There is also a Limited Edition Cobalt + Green which has been inspired by the vivid blue and green colours of the Blue Spring of the Waihou River. There is also a white colourway and a Bradley Harms Artist Edition.  

Specifications

Geometry-wise, the Koko shares a lot with the outgoing Rere with its 73-degree head angle and seat angle. Wheelbase, stack and reach numbers also remain close to unchanged with just 4mm being added to the Koko’s headtube. The biggest change in geometry is the 73mm bottom bracket drop; the additional 5mm drop offsets the larger volume tires.

The Koko is available in a broader selection of sizing as well with the addition of an XXS size. The XXS, XS and S sizes come with a 53mm offset fork rather than 43, which presumably has been done to help reduce toe overlap.

In terms of weight, the Koko’s 1,139g medium frame actually weighs a touch more than the same-sized disc-equipped Rere. However, the 90g deficit is almost completely recovered through savings in the fork and seatpost.

The frame is compatible with both Shimano Di2 and Campagnolo EPS wired drivetrains and has a T47 bottom bracket. There are the standard mounts for two bottles within the frame, with three bosses on the downtube to allow for a lower mounted cage if you just want a single bottle.

Chapter2 doesn't offer any complete builds, opting for the simplicity of a frame-only business model so customers will need to build the bikes up how they want. Our test bike came equipped with a suitably performance-orientated build, featuring mechanical 11-speed Shimano Dura-Ace and Zipp 303 Firecrest wheels. The wheels are set up tubeless and fitted with 30mm Schwalbe Pro One tyres.

Our test bike came equipped with Chapter2’s Mana one-piece carbon handlebar which is included with the frameset. Mana which means power in Maori has been superb, balancing comfort, compliance and control extremely well. Its aero shape feels well proportioned and the addition of hiding all the cables keeps the bike cleaner in aesthetic, as well as aero drag. The bar is available in 11 sizes; 80/400, 90/400, 100/420, 110/420, 120/440, 80/380, 90/391, 100x402, 110/413, 120/424 or 130/435. 

Performance

The Koko has a very distinct aero shaping to it, the scoped downtube and tucked rear wheel keep the bike tight to presumably allow for smoother airflow. It's impossible to determine how that specifically affects the bike's real-world aero performance, but what's important is that the Koko certainly feels fast and holds its speed well. 

All this aero shaping means the frameset is considerably stiffer than Chapter2’s other race bike, the Toa. The result is that despite the comfortable Mana bar, pillowy 30mm tyres and Optimised Compliance seat clamp (more on that later) the Koko still has a very race-focused, fairly unforgiving character, especially over longer distances and broken road surfaces. It's not necessarily a bad thing, those looking for the crit race bike feel will love the instantaneous kick as you stamp on the pedals and the very direct cornering characteristics. 

That means the Koko has a buttery glide on smooth tarmac, but when faced with rougher roads, you get a sense of how much stiffer the rear end and straight-legged fork are, even if it is dulled by the tyres and filtered through the touchpoints. As a result, you will want to take advantage of the generous tyre clearance, set the wheels up tubeless and pay close attention when dialling in pressures to get the optimal balance of comfort and rolling resistance for your local roads.

In my review of the Toa, I talked at length regarding how its forgiving nature really helped add grip and speed and the Koko backs that up. Our review Koko was equipped with the same spec as our Toa review bike and the aero tube profiles mean the Koko is a step ahead of the Toa in speed. While it will nose ahead over smooth surfaces, speed is harder to maintain as road imperfections and other real-world aspects can knock focus when laying down the power. The grip also feels less of a given too, the stiffness of the Koko’s rear triangle can leave the rear tyre scrambling during hard accelerations, rather than gripping to the road surface. If you are blessed with beautiful tarmac, it's another story and the Koko will push forwards with the enthusiasm you expect from a race bike.

Compared to some of the competition from the big brands, the Koko isn't going to trouble the best lightweight bikes, but this is a dedicated aero bike and its 7.4kg build (without pedals) is hardly heavy, especially when more fairly compared to other dedicated aero bikes such as the Orbea Orca Aero and the BMC Timemachine SLR 01 Two. It overcomes inclines very well too with an efficient urgency, unlike some aero bikes I have ridden that have felt far from enthusiastic when the road points up. Again the big tyres help as well with the larger tyre footprint offering a securer footing on loose or greasy road surfaces, especially if you decide to put the boot in and make a move on a steep pitch.

Equally, on the descents the advantages of big tyres offer real-world second gains by bolstering your confidence, shortening braking distances and increasing cornering speed when ducking and diving corners against 25mm tyred bikes. The big tyres really help make the most of the Koko’s sharp handling and allow the bike to be driven hard through turns.

Aero bikes are built to beat the wind but can become unwieldy when the wind fights back. Despite taking the Koko out on some seriously blowy days it did well to keep buffering to a minimum and hold a straight line, despite being swept by 30kph side winds at some points.

It must be noted that fit isn’t completely straightforward. While it has an effective 73-degree seat angle on paper, in reality the seat tube is set back from the bottom bracket and so it measures 78 degrees. I run a tall saddle height which meant I found the fit was a little more difficult as it actually resulted in an effective shortening from the seat to bar when compared to the traditionally shaped Toa I simultaneously had on test. Most riders probably won’t have the same issue as their saddle height will be closer to the 73-degree effective seat angle sweet spot, it is certainly something worth considering with any bike that shares a similar seat tube layout though.

We ran the Optimised Compliance seat clamp in both positions and despite the stiff rear end I settled on the less compliant position, there are two reasons for this. I found that while the compliance was certainly improved in the softer setting, the seatpost would flex forward and backwards as well as side to side which not only felt a little odd but also inefficient when working hard when seated. The second reason is that we had a pre-release clamp fitted that slipped just enough so we couldn’t get a tool in to change it back, Chapter2 has confirmed that all Koko frames will come with an improved clamp design.

Verdict

Strikingly fast with the rolling confidence of big tyres make the Koko feel considerably more capable than other aero road bikes I have ridden. It's a confident climber and a very capable descender with handling that is sharp and direct to take full advantage of the extra rubber and really drive through corners. 

You will want to take advantage of the big tyres as the frame and fork are stiff and, even with Chapter2’s comfortable Mana handlebar, the ride can still be on the harsh side if the roads aren’t perfect. Going tubeless and tuning in the tyre pressures can mitigate much of the stiff ride quality, resulting in an aero race bike that is extremely confident and ready to be ridden hard.

It's okay that the frame is on the stiff side, Chapter2 already has the Toa which is a superbly comfortable yet fast race bike with aero cues for those who want more compliance. That means the Koko can really focus on simply being the fastest bike it can by unapologetically sacrificing compliance for aero considerations. 

Logbook: Chapter2 Koko

• Temperature: 6-30 degrees C 
• Weather: Winter through to summer
• Road surface: paved roads, cobbles, rough tarmac, light gravel
• Mileage: 3,264 km

Tech Specs: Chapter2 Koko frameset

• Frame price (including the Mana handlebar): Starting at £3,399 / $3,649 / €3,999 / AUD$5,199
• Mana handlebar price: £619 / $699 / €699 / AUD$999
• Sizes: XXS, XS, S, M (tested), L, XL
• Colours: Glossy Black (Tuhua), Cobalt + Green, White + Grey (Tauriparipa), Koko Bharms Special Projects Artist Edition
• Frame Weight (claimed): 1,139g Size M +/- 3 per cent
• Fork Weight (claimed): 420g Uncut +/- 3 per cent
• Seatpost Weight (claimed): 135g Size M +/- 3 per cent
• Handlebar/Stem (MANA) (claimed): 395g (100-420mm) +/- 3 per cent