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Cannondale SystemSix Carbon Ultegra review

This Aero Bike of the Year contender is a complete aero package built for speed

Our rating 
4.5 out of 5 star rating 4.5
GBP £4,000.00 RRP | USD $4,750.00 | EUR €4,699.00 | AUD $6,999.00
Cannondale SystemSix Carbon Ultegra

Our review

The SystemSix is everything you’d want from an aero bike and more
Pros: Agile, light and furiously fast
Cons: Narrow tyres; lower-spec disc rotors
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Cannondale claims that its latest SystemSix is the “fastest bike in the world”, and top line wind-tunnel testing figures certainly add some weight to that with the Cannondale SystemSix generating drag of 203 watts. That’s lower than the Cervélo S5 (206W), Ridley Noah Fast (213W) and Trek Madone (212W).

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If the numbers add up, it’s partly down to the chassis, which is based on a Kammtail design.

In cycling circles, Kammtail is a teardrop shape greater than the UCI’s stringent 3.2:1 rule on design parameters. To satisfy the UCI, the end’s then chopped off and, by the miracle of physics, airflow acts like the ‘chop’ had never happened. The virtual tail keeps airflow smoother for longer thus reducing drag.

Bike of the Year 2020

The Cannondale SystemSix Carbon Ultegra is part of our annual Bike of the Year test.

Head to our Bike of the Year hub for the full list of winners, categories and shortlisted bikes, as well as the latest reviews – or read our behind-the-scenes feature on how we tested Bike of the Year 2020.

Cannondale Systemsix Carbon Ultegra
The bike features lots of aero design touches, such as an aero cover in place of a traditional four-bolt faceplate.
David Caudery / Immediate Media

In fact, aero features are numerous: the front fork is asymmetric to balance out airflow from the disc and non-disc side; the seatpost is deep and aero shaped and the low-slung stays shelter behind the deep seat tube to avoid disrupting the air.

The science adds up, it looks stunning but, of course, it needs backing up with the ride.

Cannondale SystemSix Carbon Ultegra kit

Cannondale Systemsix Carbon Ultegra
Shimano’s Ultegra with a 52/36, 11-30 gear ratio.
David Caudery / Immediate Media

The SystemSix is dressed in Shimano Ultegra and a racy but well-spread 52/36, 11-30 gear ratio. The only deviation from the Ultegra group is a step down to RT81 steel rotors over Ice Tech. These offer decent braking but at the expense of screeching when hot and in the wet.

Elsewhere, the Vision Metron 4D MAS flat aerobar and Vision Trimax QS stem are impressive. The bar’s super-deep top section leans forwards into a drop based on FSA’s compact drop shape, which is one of the best around, while the Trimax stem features an aero cover in place of a traditional four-bolt faceplate for drag reduction.

The wheels are from Vision, too. The new SC 55 DB wheelset is based around the same rim shape as the premium Metrons, namely a 55mm-deep, 24mm-wide rim with a 19mm internal diameter that’s both clincher and tubeless ready.

They’re tightly built but dish out a comfy ride. The SC 55s retail for £1,055, so it’s impressive to see them on a bike at this price.

Cannondale SystemSix Carbon Ultegra ride impressions

Cannondale Systemsix Carbon Ultegra
The bike’s geometry makes for the usual aero rapidity but also unexpected agility.
David Caudery / Immediate Media

The SystemSix doesn’t ride like aero bikes of old. That’s heavily down to the geometry: a 580mm stack (on my 58cm test bike), reach of 398mm and a wheelbase that’s just under a metre; the frame features a 73-degree head angle and a seat angle of 73.5 degrees. It all makes for the usual aero rapidity but also an unexpected agility.

On climbs, which are often an aero bike’s achilles heel, the SystemSix impresses. Lightness helps because, despite 55mm-deep aero wheels, it’s just 8.43kg, which is lower than many of its rivals.

The stiff chassis is responsive, too, and these two variables unite for a bike that revels in out-of-the-saddle ascents.

Cannondale Systemsix Carbon Ultegra
The ProLogo Dimension NDR saddle.
David Caudery / Immediate Media

As a bonus, once you’ve crested the climb, you can then take advantage of the bike’s premium handling and aerodynamics.

The SystemSix also scores well on comfort. Yes, it’s firm and stiff but it’s never rattlingly uncomfortable, even on broken surfaces – and that’s despite, on first look, the odd choice of 23c tyres. However, there’s a range rationale behind that selection…

The top-end SystemSix rolls atop ultra-aero 64mm-deep KNOT 64 wheels. Their super-wide 32mm rims have a wider internal width than the Visions, so the 23c versions on the premium SystemSix measure closer to 26mm.

This enables the air around the rim and tyre to reattach more easily and so cut drag, plus it adds comfort.

On this model, however, the smoothing of air’s diluted because of the Vision SC55’s slimmer 19mm internal width. Plus, while the graphene-infused Vittoria Rubino tyres grip superbly in adverse conditions and roll well, the narrower profile demands higher tyre pressures to avoid pinch-punctures, which dilutes comfort.

A broader tyre would help both and be more befitting of such a fantastic bike.

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Cannondale SystemSix Carbon Ultegra geometry

  • Sizes (* tested): 47, 51, 54, 56, 58*, 60, 62cm
  • Seat angle: 73.5 degrees
  • Head angle: 73 degrees
  • Chainstay: 40.5cm
  • Seat tube: 55.3cm
  • Top tube: 57.6cm
  • Head tube: 17.2cm
  • Fork offset: 4.5cm
  • Trail: 5.7cm
  • Bottom bracket drop: 6.9cm
  • Bottom bracket height: 27.1cm
  • Wheelbase: 1,000mm
  • Stack: 58cm
  • Reach: 39.8cm

With thanks to…

BikeRadar would like to thank 100%, Q36.5, Lazer, Garmin and Facom for their support during our Bike of the Year test.

Product Specifications


Price br_price, 5, 3, Price, AUD $6999.00EUR €4699.00GBP £4000.00USD $4750.00
Weight br_weight, 5, 6, Weight, 8.43kg (58cm), Array, kg
Brand br_brand, 5, 10, Brand, Cannondale


Available sizes br_availableSizes, 11, 0, Available sizes, 47, 51, 54, 56, 58, 60, 62cm
Bottom bracket br_bottomBracket, 11, 0, Bottom bracket, Cannondale Alloy PressFit30
Brakes br_brakes, 11, 0, Brakes, Shimano Ultegra Hydraulic disc, 160/140mm Shimano RT81 rotors
Cassette br_cassette, 11, 0, Cassette, Shimano 11-30
Chain br_chain, 11, 0, Chain, Shimano
Cranks br_cranks, 11, 0, Cranks, Hollowgram chainset with eight-arm Spider ring, 52/36
Fork br_fork, 11, 0, Fork, BallisTec carbon
Frame br_frame, 11, 0, Frame, BallisTec carbon
Front derailleur br_frontDerailleur, 11, 0, Front derailleur, Shimano Ultegra, braze-on
Handlebar br_handlebar, 11, 0, Handlebar, Vision Metron 4D MAS flat
Headset br_headset, 11, 0, Headset, Tapered
Rear derailleur br_rearDerailleur, 11, 0, Rear derailleur, Shimano Ultegra GS
Saddle br_saddle, 11, 0, Saddle, ProLogo Dimension NDR
Seatpost br_seatpost, 11, 0, Seatpost, SystemSix carbon
Shifter br_shifter, 11, 0, Shifter, Shimano Ultegra hydro disc
Stem br_stem, 11, 0, Stem, Vision Trimax OS
Tyres br_tyres, 11, 0, Tyres, Vittoria Rubino Pro Speed Graphene 2.0, 700 x 26mm (23c)
Wheels br_wheels, 11, 0, Wheels, Vision SC55 carbon