Cannondale Synapse Carbon Disc Ultegra review

The Synapse is Cannondale’s endurance bike offering which first appeared in 2006. The bike has evolved over four editions to the all-new 2018 model with a new carbon layout for weight reduction and an all disc brake platform with greater tyre clearance.

Cannondale Synapse Hero-2.jpg


The Frame

The 2018 Synapse frame is constructed using a new carbon layout which shaves considerable weight from the previous model. At the top of the range, using the advanced Hi-MOD carbon, Cannondale is claiming 220-gram savings on the medium model. It's almost enough to wipe out the weight gains added by the disc brake system. Unfortunately, there aren’t readily available weight claims on the standard carbon frame that we tested.


Cannondale Synapse-27.jpg

Cannondale Synapse-22.jpg

Cannondale continues to develop their SAVE micro-suspension technology on this latest Synapse frame. The bike is designed to be flexible at various points on the frame (notably the seat tube, stays, and fork). The idea is to soak up vibrations from the road surface while still allowing power to transfer uninterrupted to the rear wheel. Cannondale fits a thinner 25.4 mm diameter seat post (also found on the SuperSix Evo) for added deflection, contributing to a smoother, more compliant ride feel.


Cannondale Synapse-14.jpg
The SAVE seatpost with an integrated seat binder tighten by a bolt accessible on the underside of the top tube.


Comfort is not all down to the micro-suspension system, the Synapse’s geometry also deviates from that of a thoroughbred race bike to ensure that the rider is well positioned to enjoy the experience. In comparison with the brand’s SuperSix Evo race bike, the head tube length and stack height are increased, the head angle slightly slacker and the chainstays are 5 mm longer with a broader wheelbase. This geometry might not be overly relaxed compared to other all-road bikes but the Synapse does enough to position the rider slightly more upright with a greater feeling of control over the bike.


Cannondale Synapse-15.jpg

Cannondale Synapse-16.jpg

Cannondale Synapse-19.jpg

Front and back mounts for fenders. And a neat internal cable routing system.


To make the bike more friendly to riders of varying heights and weights through the size curve, Cannondale use different diameter tubes on the frame, head tube, and fork steerer as well as three fork rakes through the range.


While the future of disc brake standards is still unfolding on the road, Cannondale has picked the more commonly walked path using flat mount calipers and 142x12mm rear axle spacing with 100x12mm front axles. The new Synapse has also bumped up the tyre clearance to officially accept 32 mm width tyres. Some peace of mind for those looking for some kind of (near) future proofing.


Cannondale Synapse-6.jpg

Cannondale Synapse-7.jpg

Front and rear tyre spacing with the stock 28 mm Schwalbe Lugano tyres.



As the name suggests, the Cannondale Synapse Carbon Disc Ultegra is equipped with a largely Shimano Ultegra hydraulic groupset with a Cannondale Si crank and FSA chainrings.


Cannondale Synapse-18.jpg

Cannondale Synapse-26.jpg

Cannondale Synapse-25.jpg

The gearing on the Synapse is also tuned with comfort in mind. The 50/34 compact chainrings link to an 11-32 spread cassette giving the Synapse a generous range when it comes to climbing. On a number of occasions, I was more than happy to slide into the 32 and cruise up the climbs. Some riders might point to a deficiency in the low range, I found that I start spinning out around the 60 km/h mark (more than fast enough for my liking) but it is an easy fix should gravity not be sufficient.


The bike rolls on Mavic’s popular Aksium wheels, with centerlock brake mounts, fitted with 28mm Schwalbe Lugano tyres. The disc brake version does carry a bit more weight than the rim brake model. One reason is that the hubs have to accommodate for the mounting of the rotors. The bare wheelset tips the scale at just over 2 kgs, so it’s one place where a future upgrade might see some weight loss. The wheelset is strong and reliable having taken a serious pounding on rough roads and corrugated gravel during testing.


Cannondale Synapse-23.jpg

Cannondale Synapse-28.jpg

The cockpit features a Cannondale branded aluminium handlebar, stem, and seatpost with a Selle Royal Seta 1 saddle. The bar tape is also from Cannondale and offers good grip.



  • FrameSynapse Disc Asymmetric, BallisTec Carbon, Di2 ready, SAVE, BB30a, flat mount, 12mm thru axle
  • ForkSynapse Disc Asymmetric, SAVE PLUS, BallisTec Carbon, integrated crown race
  • RimsMavic Aksium Disc
  • HubsMavic Aksium Disc, Centerlock, 100x12mm front, 142x12mm rear
  • SpokesMavic Aksium
  • TyresSchwalbe Lugano, Folding, 700x28c
  • CranksetCannondale Si, BB30a, w/ FSA rings, 50/34
  • Bottom BracketFSA BB30 Bearings
  • ChainShimano HG601, 11-speed
  • CassetteShimano Ultegra R8000, 11-32, 11-speed
  • Front DerailleurShimano Ultegra R8000, braze-on
  • Rear DerailleurShimano Ultegra R8000 GS
  • ShiftersShimano Ultegra R8020 hydro disc
  • HandlebarCannondale C3, butted 6061 Alloy, Compact
  • GripsCannondale Grip Bar Tape w/Gel, 3.5mm
  • StemCannondale C3, 6061 Alloy, 31.8, 6 deg.
  • HeadsetSynapse Si, 25mm carbon top cap
  • BrakesShimano Ultegra R8020 hydro disc, flat mount, 160/140mm
  • SaddleSelle Royal Seta S1
  • SeatpostCannondale C3, 6061 Alloy, 25.4x350mm (48-56), 400mm (58-61)
  • Sizes48, 51, 54, 56, 58, 61
  • Weight8.95 kg (size 58)
  • PriceR45,000


On the road (and gravel)

When first swinging a leg over the Cannondale Synapse Carbon it is clear that the bike edges towards the racier side of the endurance road bike spectrum. The flexible design, wide tyres, and relaxed geometry do a lot to provide comfort and stability on the bike but, in doing so, the Synapse does well to maintain a performance feel.


Cannondale Synapse-12.jpg
The Synapse's carbon tubing flexes at critical points to absorb vibrations as they move along the frame towards the rider.


Though not the lightest model in the range, the Synapse Carbon Ultegra climbs with elegance. There is little indication that the frame is designed to flex while the 8.95-kilogram bike feels considerably lighter (despite what laws of physics might demand). Seated or out of the saddle, the Synapse glides up climbs encouraging you to hang onto the wheel ahead. Rather than the snappiness and vigour of a true climbing bike, the Synapse's climbing feel is efficient smoothness.


After a successful climb, the Synapse is eager for the challenge of the downhill. The combination of the bump absorption, generous tyres, commanding brakes, and accommodating geometry make for a confidence-boosting descender putting the rider firmly in control. Through the corners, the Synapse holds a line effortlessly, while the disc brakes allow greater control into the turns, and flinging the bike around tight corners feels sharp.


Cannondale Synapse-8.jpg

Cannondale Synapse-10.jpg

I'll take disc brakes and thru axles on my road bikes any day of the week.


The hydraulic Ultegra brakes are predictable with good modulation allowing for just the right amount of power to be applied. Of course, in the wet, the discs showed their true worth. My only concern became whether the tyres would hold out. On prolonged descents, like the Swartberg Pass, the brakes impressed showing little sign of fade as they heated up.


On the flats and rolling hills, the Synapse is a dutiful mile eater. The bike does well to lessen the impact of fatigue-inducing chatter and bumps over rough sections of road, allowing you to focus on keeping momentum. A familiar road bike feel greets you in the drops where you can comfortably and efficiently click over the kilometres.


Jump out of the saddle for a quick burst of effort and the Synapse obliges with a stiff, responsive, and balanced reaction. There is no blaming of the bike if you fail to close a gap or beat your mates to the top.


I felt safer on the Synapse compared to a performance-focussed road bike. Thanks to the bump absorption, large tyres, and position on the bike, I found that I could hold a line better through deteriorating road surface. A good example is when you are forced to ride alongside the gutter by close passing traffic, where the road surface is far from ideal and usually unpredictable. The same comfort and stability translated well when commuting, with the added versatility of the option to veer off the road onto the dirt verges.


Although the Synapse favours the road bike end of the endurance bike spectrum, I could not resist racing the bike over some gravel at the Swartberg 100 Gran Fondo. The only modification was maxing out the official tyre clearance with a set of 32mm Vittoria Zaffiro tyres.


SWARTBERG100 2018 14.jpg
The Synapse doesn't mind getting dirty on gravel (too much).


Over the gravel, the rear end of the bike shone, going way beyond my expectations absorbing all the abuse the countryside roads could throw at it. The front of the bike, however, proved to be the less up to the job with the fork struggling (understandably) to match the dampening abilities of the backend. The descent down the backside of the Swartberg Pass was particularly testing. That said, the Synapse proved to be up to the task on smoother gravel roads but not a first choice for bombing down a rough pass.


Cannondale Synapse-31.jpg


In the end

The Cannondale Synapse delivers a comfortable, controlled ride while maintaining a stiff and responsive feel when opening up the watts. On the all road scale, the Synapse favours performance on the tar but is more than capable of carrying you safely over broken roads and is even up for the occasional gravel adventure. It is an excellent do-it-all road bike and a worthy consideration if are looking for more comfort and control while still packing a punch when the group gets feisty.



Patchelicious, Jun 05 2018 11:40

Cool write up 👌🏼

Myth, Jun 07 2018 03:28

good looking steed...