Cannondale 2018 Synapse Hi-MOD review

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Cannondale unveiled the original Synapse in 2006, an all-carbon endurance-oriented frameset that has been steadily revised and updated since. The latest version, the fourth, builds upon the features introduced in 2014 to become a dedicated disc-brake offering with more tyre clearance for 2018.

Matt de Neef previewed the new Synapse range in July last year, and after spending a couple of days on the Hi-MOD version, was impressed with the amount of comfort the bike had to offer. Now, our Australian tech editor, Matt Wikstrom, provides an in-depth review of the 2018 Synapse Hi-MOD to see if it lives up to Cannondale’s ambitious marketing claims.

The Synapse was Cannondale’s first all-carbon frameset, and based on the model’s ongoing presence in the company’s road catalogue, it has found favour with buyers for over a decade. During that time, Cannondale has dutifully refined the Synapse, building upon its original concept of micro-suspension for a road bike.

This concept, dubbed SAVE — Synapse Active Vibration Elimination — targets the design of the fork legs, seat- and chain-stays, and the seatpost so as to attenuate shock and vibration travelling through the chassis. According to Cannondale, SAVE not only improves the comfort of the bike, but riders will also enjoy better control and handling.

Now, many of Cannondale’s bikes feature SAVE, regardless of the materials used for construction. However, it is the new Synapse where the system is at its most sophisticated, earning the moniker, SAVE PLUS. The system comprises three elements, starting with the carbon layup, which is designed to dissipate road buzz. The second element, comprising the fork legs and stays, is meant to contend with small-to-medium bumps, while the final element, the seat tube and seatpost, soaks up the biggest hits.

In developing the new Synapse, Cannondale’s engineers were intent on improving the comfort of the bike while adding back a measure of race-oriented performance. In this regard, the company’s SuperSix EVO Disc served as an important benchmark, and one important goal was to shed a significant amount of weight from the frame and fork. Another was to increase the stiffness of the chassis in key areas, such as the head tube.

Before the ride

Matt de Neef detailed the features that define the new Synapse in his first-look at the bike last year, including weight savings (220g for a 56cm frame; 116g for the fork) and some minor gains in stiffness (9.4%) at the head tube.

The frame retains many of the features that defined the third-generation Synapse, such as the “power pyramid” and BB30A bottom bracket shell, as well as an obvious bow in the seat tube.

The most obvious change concerns the brakes: the 2018 Synapse is now dedicated solely to road disc brakes, and to this end, features flat-mounts for the disc callipers and 12mm thru-axles, front and rear. The move to disc brakes also prompted Cannondale to increase tyre clearance: once a maximum of 28mm, the new Synapse can accommodate tyres up to 32mm wide.

At the time of the launch last year, Cannondale was touting a new handlebar and stem system for the Synapse dubbed “SystemBar”. Designed to provide extra compliance for the front end of the bike, it was an obvious extension of Cannondale’s SAVE philosophy. However, after encountering quality control issues during manufacturing, the company was forced to abandon the SystemBar for 2018.

The Synapse provides internal routing for the brake hoses through the frame and fork. An interchangeable cable port was also developed for the down tube of the frame that could accommodate mechanical, wired, and wireless groupsets. In addition, fender mounts were added to the fork legs and seatstays.

The geometry of the Synapse was also re-visited, and amongst the changes is the addition of an extra small 44cm size, making for a total of seven frame sizes, as detailed in the table below:

The geometry of the Synapse continues to be reasonably forgiving thanks to a taller and shorter front end compared to a typical race bike (e.g. Cannondale’s SuperSix EVO). Chainstay length is a uniform 410mm for all frame sizes, while the bottom bracket drop starts out reasonably low (75mm) for the smallest frame sizes and decreases a little (73-70mm) for the larger ones.

The fork rake also varies according to the size of the frame. The two smallest frames (44 and 48cm) are mated with a fork with 60mm of rake; 51 and 54cm frames have a fork with 55mm of rake; and the largest frames (56, 58, and 61cm) are paired with a fork with 45mm of rake. When combined with the different head angle of each frame size, this range of fork rakes provide a near-uniform trail of 56-60mm, which is unusual (but laudable) for mass-produced bikes.

Cannondale’s dedication to normalising the handling of each frame size can also be seen in the decision to scale the size of the lower headset bearing. The two smallest frames make use of a straight 1.125in-diameter fork steerer. In contrast, 51 and 55cm frames have a 1.125-to-1.25-inch tapered steerer, and the remaining sizes use a 1.5-inch lower steerer diameter. In this way, the front end of the Synapse is only stiffened when it is needed and small riders aren’t burdened by an overly stiff frame.

When placed side-by-side with the previous iteration, the new Synapse is obviously lighter and sleeker. Every frame member has been pared back and simplified to create a very clean profile. The bow in the lower half of the seat tube is the only deviation from this new aesthetic, but even this feature seems to add to the overall sportiness of the final result.

The Synapse continues to be offered in a choice of two versions: the Synapse Carbon, constructed from Cannondale’s standard BallisTec carbon fibre; and the Synapse Hi-MOD, made from Hi-MOD BallisTec carbon fibre. The latter provides a ~150g weight-saving for the frame, but adds several hundred dollars to the asking price for the bike. There are just a few builds for the Hi-MOD chassis on offer in the 2018 catalogue compared to a wider and more economical range of builds for the Synapse Carbon.

For this review, a size 51cm Hi-MOD frameset was supplied by Cannondale’s Australian distributor, Monza Imports. The frame weighed 895g (without fittings such as the seatpost clamp, headset, and thru-axle) while the uncut fork was 405g (without thru-axle). Once assembled with a SRAM eTap Red HRD groupset, carbon Hollowgram wheels with 30c Schwalbe tubeless G-One tyres, a Fizik cockpit, and a Fabric saddle, the bike weighed 7.23kg (15.94lb) without pedals.

For 2018, Cannondale has abandoned rim brakes for the Synapse. The new bike features flat-mounts and thru-axles, front and rear.

This build essentially mirrors the Synapse HI-MOD Disc Red eTap that retails for AUD$11,000/US$8,000/£6,500. Buyers opting for the Synapse Carbon Disc Red eTap build can expect to pay AUD$8,500/US$6,000/£5,000, while the Shimano Ultegra version sells for AUD$4,500/US$3,000/£2,700 compared to AUD$3,500/US$2,500/£2,200 for the Shimano 105 build.

Aside from the components, each build offers buyers a distinct colour scheme for the chassis. This may frustrate some buyers that are drawn to a specific colour, only to find that it is either out of their price range or the build does not satisfy their specific needs. In this instance, the frameset supplied for review was largely a matte-black affair with grey and white panels. Curiously, those white panels were positioned near the grubbiest parts of the bike (e.g. bottom bracket and rear dropouts), so they were difficult to keep clean.

Cannondale offers a lifetime warranty for the Synapse frame while the rest of the bike is covered by a standard one-year warranty. For more information on the new Synapse and the various builds in its catalogue, visit Cannondale.

After the ride

When Cannondale unveiled the new Synapse last year, it was clear the company was proud of the result, asserting that it was “lighter, stiffer, better handling, and faster than any other endurance race bike out there.”

Cannondale has never been afraid to make bold claims. I can still recall some of the hyperbole the company used to describe the third-generation Synapse, which promised “the perfect balance of raw power and all-day rideability [that] might just be the best all-around road bike we’ve ever made.” After spending a few weeks on that bike, I couldn’t quarrel with the amount of comfort the bike had to offer, but the ride experience was dull, bordering on lifeless.

Interestingly, in presenting the new Synapse, Cannondale seemed to acknowledge this shortcoming because the SAVE micro-suspension had been refined to become “a holistic system that insulates the rider from the bumps, without isolating them from the experience.” This stands as something of a holy grail for any bike and I had my doubts that Cannondale could achieve it.

And yet they did. The bike really is as good as Cannondale claims, and not just for endurance-oriented riders, but for road cycling in general. It’s a road bike in its most modern guise that is quick to get moving, easy to handle, and versatile enough for tackling any reasonable road surface.

To start with, the new Synapse is easily as comfortable and compliant as its predecessor. This was most obvious at the saddle, where there was visible flex in the seatpost. Vibrations simply failed to reach my backside, yet I only experienced some mild bobbing when pushing big gears while seated on the bike. There were times when I might have preferred a sturdier post and surer saddle position, but overall, I consistently appreciated the amount of comfort that was on offer.

The front end was reasonably compliant, too, however it couldn’t match the saddle when it came to absorbing shock and vibrations. At times, when the terrain was at its most rugged, the difference was enough to unbalance the bike and leave the palms of my hands feeling a little sore after a long ride (4-5 hours) on mixed surfaces. In this regard, I expect the ill-fated SystemBar would have made a difference compared to the obviously stiff carbon Fizik bar installed on this occasion.

What was most impressive was that the bike suffered none of the dullness of its predecessor; in its place was a lively, informative ride quality that I could easily connect with. There was enough feedback from the road surface for me to understand how the bike was behaving at any given time, including any changes in grip and traction, without it ever overwhelming my senses.

I spent the entire review period on one set of tyres: a pair of 30c Schwalbe tubeless G-Ones, inflated to 40-50psi. At 50psi, the tyres and the bike worked perfectly on paved surfaces, but lacked some grip on unpaved roads. Dropping the pressure to 40psi improved the amount of grip considerably, but the bike felt sluggish, so I made sure to have at least 45psi in the tyres for every outing.

These tyres were so versatile that I wasn’t tempted to try anything else. For those curious about bigger tyres, I tried to fit 35c Schwalbe G-Ones, as well as a set of 33c Schwalbe Racing Ralphs, and while it was possible to fit the rear wheel into the frame, there wasn’t enough clearance at the fork crown for the bigger casings.

The Synapse was an easy bike to ride on any paved terrain. The steering was close to neutral with a little understeer at high speeds, but the inherent stability produced by the combination of a slack head angle (71.7°), low bottom bracket, and generous fork rake (55mm) made for an extremely sure-footed and confidence-inspiring machine that was still highly manoeuvrable.

If anything, the steering and handling of the Synapse was even better suited to unpaved surfaces. The steering was very forgiving, even in the dry and dusty conditions that prevailed during the review period, and I was able to negotiate some pretty challenging terrain. At the same time, the rear end of the bike remained firmly planted, even when I was out of the saddle climbing steep trails and looking to accelerate out of a tight corner.

That’s not to say that the Synapse was a gifted off-road bike in absolute terms. The tyres were simply too slim to conquer loose, sandy, and/or rocky trails, but with some care and a lot of concentration, I could pick my way through it all without losing control of the bike. The handling of the bike was always predictable and I found myself revelling in the challenge of riding off the beaten track to enjoy a strong sense of exploration.

The most satisfying aspect of these unpaved adventures was that I was able to ride to and from all of the trails on a very capable road bike. Indeed, the Synapse actually rivalled the stiffness, responsiveness, and liveliness of the SuperSix EVO Disc, with the only major difference being the quality of the steering and handling. And in retrospect, I found I preferred the Synapse because of the extra stability and sure-footedness it had to offer.

Some of the Synapse’s impressive performance could be attributed to the aspirational build and the low final weight. To date, it is the lightest road disc bike that I’ve ever ridden, and I found it lived up to the performance standards set by some of the lighter rim-brake equipped bikes I’ve experienced, such as Canyon’s Ultimate CF SLX and the Scott Addict.

Another aspect that probably helped the performance of the bike was the fact that I was able to go down a frame size with the Synapse. I normally ride a 54cm frame, but in the case of the Synapse, the front end of the 54 was taller than I wanted. The stack of the 51 was near-perfect, and while the frame was a little short (~5mm), I was able to get close to my ideal fit with a 120mm stem.

As can be seen from the photos, a size 51 is a very compact frame, and I’ve consistently found that compact frames benefit from a little extra agility. This effect may have something to do with the inherent stiffness of a smaller frame, or perhaps it is simply a matter of weight distribution. Whatever the reason, the bike was always eager to move; when coupled with the quality of the build, I was able to enjoy a race-worthy bike that was as responsive as it was versatile.

This is the second build where I’ve been able to make use of SRAM’s Red eTap HRD (Hydraulic Road Disc) groupset, and it continues to be a reliable and effective performer. The shifting action falls in between that of a mechanical groupset and the wired electronic groupsets (i.e. Di2 and EPS): for the best results, it is necessary to lighten the load on the pedals when shifting, just like a mechanical groupset, but the same kind effort isn’t required at the levers. SRAM’s Blip remote buttons make for convenient shifting while on the tops, too.

As for the rest of the bike, it was trouble- (and creak-) free for the duration of the review period. The only thing that interrupted the smooth, quiet running of the bike was some chain slap when riding rough terrain while using the small chainring and sprockets.

Summary and final thoughts

The last few years have seen the number of choices available to road cyclists increase dramatically. There are now several distinct road bike categories (race, endurance, all-road, gravel, etc.) and a variety of polarising equipment options (rim versus disc brakes, mechanical versus electronic groupsets, 2x versus 1x transmissions, etc.). Both are a clear sign of evolution in the marketplace, and while it may overwhelm shoppers, there is the promise of a bike that is better suited to any rider’s specific needs.

So where does the Synapse fall within the realm of possibilities? It’s a road bike that many riders will be able to use with supreme confidence on a wide range of surfaces to add variety to their cycling. It’s not so rugged to be considering a dedicated gravel-grinder, but it isn’t that far removed, either. Better yet, it retains the poise and responsiveness of a dedicated race bike without forcing the rider to compromise on comfort or the quality of steering and handling in less-than-pristine conditions.

As such, the new Synapse is a worthy rival for Trek’s Domane and Specialized’s Roubaix. In fact, I’m sure both were being targeted when Cannondale asserted that the Synapse was “lighter, stiffer, better handling, and faster than any other endurance race bike out there.” I’ve not spent any time on either of those bikes, so I can’t make any direct comparisons, but based on James Huang’s impressions, the Synapse seems an edgier and more aggressive bike that isn’t weighed down by suspension units. And it’s for this reason that it holds more appeal for me than either of those bikes.

What do each of the individual ratings criteria mean? And how did we arrive at the final score? Click here to find out. You can also read more about our review process.

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