Cannondale Synapse Carbon Women’s Ultegra Di2 review

The best all-round women’s bike we’ve tested

Our rating 
5.0 out of 5 star rating 5.0
AUD $5,799.00

Our review

With its versatility and relative affordability, this bike will knock your cycling socks off
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With so many ride-specific bikes on the market, it can sometimes feel like a different bike is needed for every ride. Going climbing? You need a lightweight climbing bike. Racing a crit? Use a super-rigid race bike, of course. Going for a long ride? An endurance bike is a necessity.


But what if you want just one bike for all of the above? Turns out Cannondale has created a dream machine to fit the bill. Meet the women’s-specific Carbon Synapse Ultegra Di2.

  • Highs: Supreme versatility – a super smooth ride that handles like a race bike
  • Lows: We’re still looking
  • Buy if: You want one bike for training, racing, adventures and endurance rides

Ride and handling: comfort and performance without compromise

I have to own up to some initial apprehension around saddling up an ‘endurance’ bike, largely because of two common racer’s assumptions about the breed: slow handling and a touristy handlebar height. However, the Synapse proved each of these speculations wrong as it flew around corners and down steep mountain descents.

Such was my faith in the Synapse’s racing ability that I chose to race it this spring at the Rouge Roubaix 100-mile road race in Baton Rouge, Louisiana. The race consisted primarily of pavement but had several loose dirt and gravel sections. The Synapse performed perfectly, cruising along the bumpy dirt roads on its 28mm tires while confidently attacking steep climbs.

That climbing ability is down to this bike being built with Cannondale Women’s SERG (Synapse Endurance Race Geometry), which expertly treads the line between comfort and agility to create a beautiful ride.

Thankfully the sensible top tube height means racers needn’t go too crazy with negatively angled stems:

The sensible top tube height means racers needn’t go too crazy with negatively angled stems

In keeping with its endurance tag, the Synapse has a typically tall head tube at 18cm (size 56). This makes getting into a comfortable, more upright position easy to achieve without crazy stems or tons of spacers. However, the head tube isn’t so outrageously tall that the bike can only be ridden in an extreme upright position.

For comparison, the Synapse’s head tube is 1cm and 1.5cm shorter than the Specialized Ruby and Trek Silque women’s endurance bikes respectively. What this means in practice is being able to mimic a race position without an obscene negative-angled stem, which can be necessary on other endurance bikes. The midrange head tube height is very versatile and will suit a large range of rider positions.

Frame and equipment: precision-engineered smoothness and ultra-reliable spec

Tube design plays a key part in keeping the Synapse both agile and comfortable. The rear triangle’s helical shaped seat- and chainstays stabilize the bike over rough roads. A sculpted fork helps lessen harsh bumps. And finally, the bike’s Power Pyramid seat tube splits just above the BB30A bottom bracket to maximize stiffness while reducing weight.

Cannondale’s SAVE PLUS Micro-Suspension, meanwhile, puts carbon layup technology into service at various points on the frame to absorb small bumps and vibrations while withstanding side-to-side forces. Perhaps more importantly, the Synapse’s 25.4mm diameter seat post and internal wedge seat clamp work together allowing more flex – and thus comfort – than larger posts. Add that to a seat tube that is designed to bow under load, and you have a very smooth ride.

Fat 28mm rubber aided in comfort and made our dirt-road explorations a puncture-free pleasure:

Fat 28mm rubber aided in comfort and made our dirt-road explorations a puncture-free pleasure

Those big-volume Schwalbe ONE 28mm tires don’t do any harm either when it comes to delivering smoothness at speed. Bigger tires also help prevent pinch flats, so you’ll spend less time stopping mid-adventure to change annoying punctures. I suffered neither flats nor mechanical issues while testing the Synapse, despite leading it off on some not-so-road-bike-friendly trails.

Some might argue that a top-line machine such as the Women’s Carbon Synapse should be specced with Dura-Ace Di2 rather than the 11-speed Ultegra Di2 it comes with, but I’d disagree.

Ultegra Di2 might be a little heavier than Dura-Ace, but the second-tier shifting group makes this bike more affordable without any noticeable performance sacrifice. The Ultegra rear derailleur also allows for a 32-tooth cog, while Dura-Ace can only handle a 28t. For endurance bikes, a wide range of gearing is greatly appreciated, especially on long climbs at the end of an even longer day.

It’s also worth mentioning that the Ultegra shift levers can be adjusted to suit different sized hands. Many women who have small hands struggle to securely grasp the brake lever, which can create dangerous riding situations. However, Shimano 11-speed shift levers are easily adjusted for a shorter reach to accommodate these small hands. While adjustable reach isn’t unique to Shimano shifters, it’s an important feature.

Ultegra may be slightly heavier than dura-ace, but its 32t cog comes in very handy and the overall cost vs performance equation comes down on the side of the cheaper groupset in our opinion:

Ultegra may be slightly heavier than Dura-Ace, but its 32t cog comes in very handy

Speaking of important details, if – like this tester – you’re a sucker for matt-black bikes, you’ll find plenty to love here. While vibrant paint jobs and catchy patterns have their place in bike design, the classic elegance of a black carbon bike will never go out of style. One small, understated touch of femininity comes courtesy of its glittery silver and green accents.

The Synapse comes with an integrated LED light located in an optional headset spacer. This is a fun and enlightened touch that also adds an extra layer of safety for those dreary or rainy days on the road. However, for riders who prefer simplicity, the Synapse also comes with standard headset spacers.

If you’re desperate to seek out negatives, well, the Synapse is more than 1lb/500g heavier than the Trek Silque and only lighter by a similar amount than the Specialized Ruby, which includes heavier disc brakes. However, at 16.7lbs (size 56), it’s hard to call that a major flaw.

That’s a seriously tasty matt-black finish:

That’s a seriously tasty matt-black finish

On a more personal note, the Synapse comes with a Fizik Vesta women’s saddle – as the largest and most sensitive contact point of the bike, another key factor in ride comfort. It didn’t work for me, but it is a sensible choice that many women get on fine with.

The Vesta has a central channel that relieves pressure from sensitive areas without compromising saddle stiffness. It’s more padded than other Fizik women’s models, which is most appreciated at the end of a long day on the bike.

Bottom line: the best all-around bike we’ve tested

Coming from a racing background, endurance bikes have never been my first choice. However, the Cannondale Synapse is a bike capable of converting skeptics into believers. The blend of smooth and stable ride plus agile and responsive nature introduced a whole new way of riding – my favorite dirt roads and long mountain climbs became even more appreciated adventures.


For cyclists who want more out of a bike, the Synapse can tackle long rides over bumpy terrain while also performing perfectly in a technical crit. If all this wasn’t enough, this Synapse also delivers the best bangs-per-buck of any women’s endurance ride we’ve tested.

Product Specifications


Name Synapse Carbon Women's Di2
Brand Cannondale

Brakes Shimano Ultegra 6800
Saddle Fi'zi:k Vestra, with Mg Rails
Weight (lb) 16.7
Year 2015
Wheelset Fulcrum Racing 5
Weight (kg) 7.57
Stem Cannondale C2
Shifters Shimano Ultegra 6800 Di2 11-speed
Seatpost Cannondale C2, carbon, Di2 battery
Rear Tyre Schwalbe ONE, 28mm
Cassette Shimano Ultegra 6800 11-speed 11-32
Rear Derailleur Shimano Ultegra Di2 6870
Handlebar Cannondale C2 Women's Compact Wing
Front Tyre Schwalbe ONE, 28mm
Front Derailleur Shimano Ultegra Di2 6870, braze-on
Frame Material Carbon
Fork Carbon
Cranks Cannondale HollowGram 50/34
Chain Shimano HG700, 11-speed
Frame size tested 56cm