What is the Best Aero Bike of 2019?

The latest superbikes from Cannondale, Factor, Specialized and Trek make up an aero fortress


Call it coincidence maybe, but how is it you might wonder that an industry that fancies itself as a collective of independent-minded brands with a high level of proprietary design and marketing skills would find themselves simultaneously using the 2019 model year to launch all-new aero road bikes?   

So coincidental, in fact, that you could be excused for imagining that an industry-wide memo must’ve made the rounds alerting the manufacturers that this would be the summer when the aero road market would be revitalized with all-new bike designs. 


As we all know, wind forces have always been a cyclist’s own worst enemy in terms of going faster. Aero road bikes, best thought of as a hybrid between a road and TT bike, have existed in one fashion or another for decades. However, it’s only been in the last decade or so that they’ve been an actual category of road bike. 

If the summer of 2018 is remembered for anything in the sport, it will be the season that all the major brands unleashed their aero weapons of war in the battle for group-ride and pro-peloton supremacy. 

Sensing the aero battle to come, we put forth a mighty effort to collect some of the most talked-about aero road bikes that consumers would be talking about—the Cannondale SystemSix, Factor One, Specialized Venge and Trek Madone. 

If there was one immediate take-away of the breed at large, it’s that the new age of aero road bikes is more complicated to manage. Although (thankfully) nowhere near as overwrought and excessive as your run-of-the-mill tri bike, neither are they as simple to ride and operate as those dowdy, good old-fashioned road bikes that most of us have grown accustomed to. 

In fact, one example of how serious Cannondale and Specialized took their efforts in creating their own versions of the fastest bike is that they each created their own “white papers” (18 and 28 pages, respectively) to document the science behind their designs.


  • Deeper wheels sure look sexy, but they also catch the wind and can adversely affect steering.
  • Deeper rims require long-valve (80mm) inner tubes, which cost twice as much as regular tubes.
  • So much “system integration” means reduced component and upgrade options.
  • Aero frame designs usually require more carbon, which results in added weight and a stiffer ride.
  • A sign of the times—dedicated handlebar/stem combos and steering stops are now a thing.
  • A sign of the times—every bike tested is disc brake-specific.
  • Each of the models tested costs over $11,000. Only Cannondale, Specialized and Trek offer less expensive, complete versions but Factor does offer a frameset.



Cannondale reintroduces an all-new and all-faster SystemSix

Talk about a do-over; Cannondale’s new SystemSix is a far stretch from the road bike (standard aluminum rear end mated to a carbon front triangle) that initially bore the model name. For all-around road duties, the popular SuperSix EVO became the bike of choice in the Cannondale catalog.

For 2019 Cannondale has rolled out the old name attached to a completely new bike, one that Cannondale elaborately points out in their “white paper” that has been plotted to account for every aspect and direction of wind. This is a ground-up new design that’s delivered a frame with very purposeful angles, curves and shapes.


As best we can remember, Cannondale was the earliest adapter of the System Integration design concept, and they splashed the words all around their catalog of bikes. The SystemSix is definitely a bike that can rightfully boast of such design characteristics. Just looking at how the fork mates with the downtube is really eye-catching. 


Like all the bikes in this test, the Cannondale runs with fully integrated cables; however, it is not dedicated specifically to electronic drivetrains. The front brake hose is routed through a unique external shell that sits off the head tube. 

One deceiving aspect of the bike are the faux thru-axles. The SystemSix is the first test bike we’ve ridden with a version of Mavic’s Speed Release thru-axles that actually rely on slotted dropouts for (as the name implies) faster on/off use. 

We like the three bottle-mount options with two on the downtube—one (higher) for easy reach and one (lower) for less airflow interruption.



The high-end model runs a Shimano Di2 Dura-Ace drivetrain with the addition of an SISL2 crank and Power2Max power meter that needs a computer (and an activation fee) to be a useful training partner. 

At first glance we were put off to see 23mm tires mounted on the 64mm-deep HollowGram Knot wheels. But, as part of the new-age benefits of wider-wheel trickery, thanks to the 21mm internal width of the rims, the Vittoria Rubino Pro Speed tires are expanded out to a more robust 25mm width. The carbon hoops run a 20/24 front/rear spoke count, are tubeless-ready and are slowed by Shimano hydro disc brakes.  

Designed to maintain an efficient aero tuck, the Cannondale handlebars are on the narrow side.

Like all the other bikes tested here, the Cannondale relies on an integrated handlebar/stem combo of their own making. Sharing the new Knot brand name, the aluminum stem clamps a purposely narrow (39cm top/40cm at the drops) aero carbon bar with a minimal amount of rotational adjustment. The aero seatpost is topped off with ProLogo’s version of the new-style shorty saddle. 


The SystemSix is essentially an aero SuperSix with updates that bring it up to current standards. The geometry charts are nearly the same other than the position of a few tubes to optimize the aerodynamics. On our first ride we spent about an hour fussing around with the Power2Max NG Eco power meter; we were getting cadence but no power numbers. After switching computers a few times, they all had the same result. Turns out the power meter is shipped without the firmware to deliver power, and to get it, you have to shell out another $500 for the Power2Max firmware.

It looks and works like a standard thru-axle, but the Mavic Speed Release system still uses a slotted dropout for quick changes.

After realizing that our glorified cadence sensor was not going to offer us any power figures, we finally hit the road. First thing you notice is how incredibly stiff the bike is. No matter what speed we were going, we felt like we were going fast and on the edge. Initially, we thought maybe we put too much pressure in the 23mm tires that measure 25mm on the wide rims.

After dropping a few psi (down to 80 psi in the front and 85 in the rear), the sensation was still there with almost no noticeable difference. This feeling is fun and exhilarating but made it difficult to feel when we were truly on the edge pushing its limits. The loss of SAVE tube shaping (what Cannondale calls “micro-suspension” better understood as effective compliance) means that the rear end of the SystemSix is stiff and tracks much better than the SuperSix.

Five hundred dollars short of a complete package.

We got in trouble on a few occasions while descending as we pushed the bike harder and harder trying to see if we could feel that point where things started to get loose. The handling is responsive and predictable, but the amount of road feedback you get makes it very difficult to decipher that transition between too much and just enough. Let’s just say it sure does deliver an exciting ride. 

The bike is stiff everywhere, and we wouldn’t describe it as compliant in any way. Climbing feels very efficient, and the power goes straight to the ground. Long in-saddle efforts do take their toll due to the lack of compliance, but the racer in us didn’t mind on rides under 75 miles.

As much as we understand the aero science behind a narrow front end, that didn’t take away from having to get used to such narrow handlebars. 



One of the unique things about aero bikes is the psychological impact that riding them can have on the rider. The bike is intended to be fast. It looks fast and, quite often, it can feel fast. That, in a nutshell, defines our experience with the SystemSix. Judging from the reaction the bike received in the group rides, the Cannondale was deemed fast just by looking at it. As one fan of the design said, “If Batman rode a bike, that would be it!”

We were struck by the fact that Cannondale opted to not utilize any of their popular SAVE tube shapes with this bike, despite being found on their Slice triathlon bike. As such, the ride quality, along with the rider position, contributes to a very serious and fast feel, just not one that would be our first choice for a 100-mile-long Gran Fondo. 

It’s nice to see that Cannondale expended the extra effort to create a family of five SystemSix models that start at a $4000 entry-level version.


  • Helmet: Oakley ARO3
  • Jersey: Sugoi RS Century Zap 
  • Bib: Rosti 
  • Shoes: Giro Empire SLX
  • Socks: Garneau
  • Glasses: Giant Stratos Lite NXT Varia


Price: $11,000

Weight: 17.06 pounds

Sizes: 47, 51, 54 (tested), 56, 58, 60, 62cm







Have a serving of some Euro flair

Unlike the three other brands of bikes in this group test, Factor is the definite outlier, and unlike the decades-long legacy of building bikes like the other three brands, Factor can make no valid claim to a storied history of bike production. The design and engineering firm that created the bike opened shop just over a decade ago with a focus on automobiles and motorcycles. It wasn’t until two years later when they took pen to paper to design their first bicycle project.

However, despite being short on time, they have nonetheless made up for that by designing some noteworthy bikes, along with providing some solid Tour de France results courtesy of the AG2R team they sponsor.

The One can trace its lineage back to the radical Factor Vis Vires, which graced the cover of RBA back in 2010. While intriguing to look at, the bike was a bit complex and self-indulgent. The One is a much more simplified and purpose-built machine.  


The integrated seat binder is as aero as it gets.


As unique as the split Twin Vane Evo downtube design is, in a historical context, it really isn’t unique at all. Still, as far as we know, Factor is the only brand using the visually alluring design detail on a modern bike. 


In fact, while the same can be said of their OTIS (One Total Integration System) fork with the external head tube, there is no getting around that the steering system is as dynamic as they come. In terms of the internals, there is a small rod and compression ring inside the traditional steerer column that keeps things tight, while the external structure is responsible for steering the wheel.


The One’s clean lines are definitely enhanced by the continuous frame structure that melds the Twin Vane downtube right into the chainstays. Factor also touts their wide-stance seatstays for providing a more efficient pass-through of air; we were just happy that there was room for a 28mm tire. 


In addition to the cable-free exterior, an immediately recognized (and appreciated) feature of the Factor frame is the high-luster finish, which gives the bike a real luxury Euro feel. The One is available as either a disc or caliper brake-specific model and in seven sizes.

The steering input provided by the OTIS fork was more than apparent, especially when cornering at speed.


Our test bike was driven by a Shimano Di2 Dura-Ace drivetrain and slowed by a pair of flat-mount hydro disc brakes. The wheels are secured by handle-less 12mm skewers, so don’t forget your multi-tool when you leave the house.  

Like so many other brands, Factor, too, has forged their own path in wheel and component choices. Like the seatpost, the one-piece OTIS handlebar/step combo is an obvious choice given its system-dependent design. Combining a non-sweep Kammtail shape with an 80mm drop, the OTIS bar was the most well-liked due to it being the least particular. The seatpost was easy to use and adjust (something that’s getting harder to find as design complexities rise). 


The Black Inc. wheels are of Factor’s own origin. We liked that they were not as deep as those found on the other bikes, but we’re not sure what they bring to the table that’s so special other than being sourced as an in-house brand




Of the four aero bikes tested, the Factor is easily the least like all the others. This is a race-oriented bike pure and simple. The bike feels stiff throughout, and the double downtube does help provide a very rigid connection from the head tube to the bottom bracket. 

While we’re not big fans of one-piece handlebar/stem combos, the shape and style of the OTIS unit on the Factor were the best received in the group.

Using the word “quick” to describe its handling would be an understatement. This is a bike that demands a confident, all-hands-on-deck type of rider. We did find that if you mis-judged and changed lines, the bike would respond immediately, but on fast descents, we had moments where we’d be forced to counter-steer heavily just
to point the bike where we needed to go. 

When the road went up, the bike was stiff, and you felt like every watt of power was going straight into the pedals for cannonball-like acceleration. Owing to its architecture, this was not an overly compliant ride, but never did it rate as uncomfortable. While the bike is very fun to ride, we’re not sure we would choose it for many all-day-long rides when fatigue could limit our level of attentiveness.


Within this group of aero bikes, when it comes to the Factor’s price, it’s hard not to sound like a broken record. Somewhere along the way someone thought that nearly $13,000 was a good price to ask for a complete bike. Wow! In that context, what actually comes out looking like a good deal is that Factor will sell the frame, fork, bar/stem, seatpost, bottom bracket and headset with CeramicSpeed bearings for $5549. That’s actually a price not out of line of many other high-end framesets on the market.

As much as all the bikes tested here are designed to be ridden aggressively, the Factor was the one bike that seemed to insist on it. Thanks in part to a 98cm wheelbase, it’s easy to flick and quick to accelerate.  

Despite being the new kid on the block, Factor has already shown a talent for producing impressive performance bikes. Our last outing on one was with the O2 road bike with disc brakes that wowed us with a sub-15-pound weight (RBA, May 2017). 

Whether or not you would feel the need to try and rationalize such a purchase is up to you. If we were to lend any aid in that pursuit, it would be this: of all the bikes tested here, the Factor is the one that has a distinct feel of being something truly exotic. Showing up to the group ride on the One is like bringing a sophisticated Euro sports car to a rally for Nissans and Chevrolets. While it can be a handful on fast descents, it looks and feels like something special.


Price: $12,550 

Weight: 16.75 pounds

Sizes: 46, 49, 52, 54 (tested) 56, 58, 61cm



  • Helmet: Lazer Blade
  • Jersey: MSTina Maglia
  • Bib: MSTina Panta
  • Shoes: Giant Surge Pro
  • Socks: Fitter Lives
  • Glasses: Tifosi Allian




As much as some people like to give Trek a hard time for their role in the doping debacle of Lance Armstrong, we think they should get some credit for hanging onto the model name of a bike that was originally inspired by the Texan. 

The Col de la Madone is a popular climb outside of Nice, France, and it was literally the one test that Lance would annually partake in to test himself for the rigors of the three-week-long Tour de France. Up until 2003, Trek’s high-end race bike was the 5900, which was based on the same long-in-the-tooth frame that had been serving racers for a decade. 

No doubt the moment Lance answered “yes” to the six pointed questions that Oprah Winfrey wasted no time in asking during his televised confessional, there was a meeting at Trek HQ in Waterloo, Wisconsin, wondering what to do with a bike that was named in his honor.

Luckily, they didn’t cave because, even though Lance is gone, the climb is still there, and it’s that legacy that should be honored.


In the years since Lance quit racing, returned, then quit again, the Madone has continued to evolve. For 2018, it is safe to say that there is probably no other bike in the world that has kept the same model name but changed so drastically as the Madone. It is nothing like the bike from 2017, let alone 2013. 


The Madone looks like it was designed by an automotive concept team. Owing to their design cues and shaping of the Kammtail Virtual Foil tubes, the lines of the 700-series OCLV frame are long, and hidden under them is a lot of innovation, chiefly the adjustable IsoSpeed suspension (or “compliance” feature as Trek calls it). 

Although it mimics a one-piece handlebar/stem combo in appearance, the carbon parts are actually separate and (slightly) adjustable.

For 2019 the sliding Isospeed adjuster has been moved to the underside of the top tube. Also new is the use of a rebound bumper to further soften the small but noticeable amount of compliance.

From the tapered, hourglass-shaped head tube all the way back to the rear thru-axle, the Madone is certainly a sight to behold. Owing to the short 100mm stem, the 25mm offset in the seat mast was a welcome feature.


As you’d expect from a bike with this pedigree, the Madone runs a Shimano Di2 Dura-Ace drivetrain. Makes sense, right? However, what no one could fathom was the reasoning behind Trek’s decision to spec the Madone with a compact (50/34) crank. Really? An aggressive, fast-paced aero road bike with gearing best suited for mountain goats? For us, a mid-compact would’ve been a better choice as an in-between choice.  

The Isospeed system has been redesigned with an adjustable slider located on the underside of the top tube.

As expected and delivered, the Madone is replete with everything available from their in-house Bontrager catalog. The tubeless-ready, 60mm-deep Bontrager Aeolus XXX 6 wheels run with DT Swiss hub internals and a 21mm internal width.

As for the aero handlebars, they are only meant to be partially taped, which leaves the uppers slippery with sweat. Although you can rotate the handlebar +/-5 degrees, owing to the aero shape, they were best left flat. 


The first pedal strokes on the Trek takes some setting up. As we always do, we set the IsoSpeed adjustment to the softest setting, allowing the seat mast to flex along the top tube and maximize compliance without affecting frame stiffness. 

Owing to the size and shape of the frame tubes, the overall Madone frame is stiff. Descending and cornering are confident and precise as the bike offers a responsive and controllable ride. The Isospeed definitely plays a role in maintaining descending control over irregular road surfaces. 

When things started going uphill, the Madone does feel sluggish when you start to throw it around. Some riders felt the bike just didn’t have the quick response snap to it due to the weight and effects of the Isospeed damping.  On the flip side, if you adjust the Isospeed slider, the snap returns but the compliance goes away. 



On an aesthetic point alone, the Madone was far and away the most divisive when it came to its design. People either loved it or didn’t; there was no in-between. Thanks to their wide variety of stock to Project One paint options, there is also no other bike that ended up looking as strikingly unlike any other in the group ride.

As for the ride, the Madone once again stood out in the comfort category due to the Isospeed rear end. We’re not sure where Trek-Segafredo rider John Degenkolb adjusted his Isospeed, but the compliance provided certainly makes his win on the cobbled Stage 9 at this year’s Tour de France make that much more sense.  

Without a doubt, the standout feature of the Madone remains the Isospeed system. The only downside to Isospeed is the added weight it brings, which leaves any potential buyer with one important decision to make—comfort versus weight? 

Kudos to Trek for making the Madone available with so many size and color options. For the many of you without 12 large hidden under your pillow, you can score the lower-line Madone SLR 8 Disc for $8500 and the Madone SLR 6 Disc for $6000. Of course, if spending $11,500 is insufficient, for an extra $500, there’s the SRAM E-Tap model on tap. And for those of you willing only to give a half-embrace to modernity, the Madone is also available with old-school caliper brakes.


Price: $11,500

Weight: 17.18 pounds

Sizes: 50, 52, 54 (tested), 56 ,58, 60, 62cm



Helmet: Bell Overdrive

Jersey: Pearl Izumi Elite
Pursuit Speed

Bib: Bontrager RLX 

Shoes: Vittoria Velar

Socks: Mint the Chutney

Glasses: Tifosi



The Venge returns, only this time we’re interested

If ever there was a bike that enjoyed one of the most celebrated launches in history, it would be the Specialized Venge in 2011. First unveiled at an over-the-top fête at McLaren’s F1 headquarters in England (where the bike was co-developed), less than 24 hours later, HTC/Columbia rider Matt Goss rode the svelte aero road bike to a huge win at Milan-San Remo. The weekend couldn’t have been better scripted for a bright future to come. 

Unfortunately, in the years that followed, the Venge was recreated in ever-more flamboyant permutations as it has chased the outer limits of aero efficiency. The bike became increasingly heavy, complex and even ridiculed. We still recall the day in 2016 when we sat on the viewing deck inside Specialized’s own wind tunnel as the radical Venge Vias version was first rolled out. Almost immediately our eyes rolled over as it became obvious that nothing short of the patience of a saint and skills of a pro mechanic would be required just to set up the rider position.

Of course, the most notable feature of the bike were the integrated brakes designed to maximize the bike’s wind-cheating abilities. Unfortunately, as innovative as they were, they didn’t stop very well. This unfortunate fact was highlighted when Mark Cavendish resorted to his old bike (with standard caliper brakes) in the Tour de France due to the lack of efficient braking.  


For the 2017 season, Specialized wisely lost the integrated brakes, switching instead to good old-fashioned disc brakes. Midway through last year we began hearing rumors of a new Venge, and we wondered what the chances would be that Specialized would once again wind up lost in the aero wilderness with the new bike. Only time would tell.

On the day before the Amgen Tour of California time trial this year, we once again found ourselves in the spectator gallery inside their wind tunnel ready to witness the relaunch of the new Venge. With the curtain pulled away, we sat looking at a black (of course) bike that easily had more in common with the visual cues of the original 2011 bike than any of the wavy/esoteric creations that had followed it. 


After all the swoopiness of the previous bike, it’s nice to see the new Venge retain a more traditional profile while also losing a claimed 460 grams in the process (for a complete bike). Like all of their S-Works models, the Venge uses the brand’s high-end FACT 11r carbon for the frame. Not only is the bike designed to be disc-specific, but it is also dedicated to electric drivetrains as well. Of course, leave it to Specialized to add an extra touch of slick thinking by relocating the plug for the Di2 junction box in the back of the seatpost. Clever.

As far as the numbers go, by far the most significant is the bike’s 15.75-pound weight, which is a number envied by many non-aero road bikes. Our 54cm test bike had a 97.8cm wheelbase with head and seat angles coming in at 73 and 74 degrees, respectively. 


The Venge runs a Shimano Di2 Dura-Ace drivetrain with an S-Works power crank and 52/36 chainring mated to an 11-28 cassette; it’s all about speed! 

Like most every other aero road bike, the Venge has dropped seatstays.

Just as Trek has done with Bontrager, over the years Specialized has invested heavily into making their house brand Roval wheels a recognized performance brand. The 64mm-deep, tubeless-ready wheels roll on CeramicSpeed bearings and DT Swiss 240 hub internals with a 21/24 front/rear spoke count. Helping to keep things light are a pair of 26mm Specialized Turbo Cotton tires.


On our first few rides the Venge felt very efficient, but most impressive was how confidence-inspiring it was. High-speed descents with tight turns felt natural and had us pushing our boundaries. The deep wheels spin up exceptionally quick, and the bike climbs just like the current Tarmac. The in-saddle compliance is a bit stiffer than the new Tarmac, but when you compare the Venge to the previous Tarmac, it is more comfortable. 

The bottom bracket is stiff, and having the power meter stock means that there is added value. After many rides and truly analyzing the ride characteristics, it was everything the new Tarmac was but with some solid aero tweaks. 

The Venge handlebars were the least favored in the test.

The bike feels fast, but not the kind of fast that has you feeling like you are on the edge and feeling every high-frequency bump. It is more like a smooth, well-oiled and efficient feeling that rides the line of stiffness and comfort perfectly. 

What do you give up for that aero optimization? Not much, if you ask us, and the aero gains most likely give you an advantage. The 64mm-deep wheels are 200 grams heavier as a set over the 50mm versions that come on the Tarmac. The stem and bar combo are slightly adjustable, and aftermarket alternatives can be fitted—something we would most likely do as the sweep on the aero bars was not liked by anyone. 

Given its shape, the seatpost doesn’t have the same level of compliance as the new Tarmac, but compared to the previous Venge or even the previous Tarmac, it does lend more comfort.  Obviously, the aero tube shapes add a bit to the frame weight, but this bike was still the lightest of the bunch. Bottom line? This is a road bike with aero-optimized qualities.


We were happy to see the Venge return to a simpler form. Making us happier still was that by chasing less complex design parameters, the bike’s overall performance and ease closely mimicked that found on their standard road bikes, which we remain fans of. 

If your druthers are anything like ours, then you’d see the Venge for what it is—a high-performance aero road bike that costs more than what we would ever spend on a bike. That’s why we would instead point you towards the Venge Pro, which runs with a Di2 Ultegra drivetrain and costs $4500 less. However, if your druthers are nothing like ours, you might actually find more interest in the Peter Sagan version that costs $13,250.


Price: $12,500

Weight: 15.75 pounds 

Sizes: 49, 52, 54 (tested), 56, 58, 61cm


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