For many riders, the Cervelo S3 is a hard aero road bike to beat. It offers Cervelo’s most versatile performance road geometry and thus fits a wide range of riders.  It is mechanically pretty straight-forward and relatively simple (for a competitive aero bike). It is reasonably light with a frame weight of around 1000 grams. It has CdA (aerodynamic drag) numbers that compete with top of the line superbikes. It has enough lateral stiffness for all but the most powerful of pro sprinters. It offers ride quality that is not far behind some of the class leading non-aero bikes (including Cervelo’s own R series). It can even accommodate wider tires (often up to 30mm) safely and thus can even handle many firm and maintained dirt roads. In many ways, the 2019 Cervelo S3 defines what a performance endurance road bike should be.

Available in both disc and caliper brake versions, if it fits you well, the 2019 Cervelo S3  is comfortable enough to ride all day and fast enough to win most any race.

What has changed on the 2019 Cervelo S3?

There are four primary changes to the S3 for 2019.

Tire Capacity

The first is an increase in tire width capacity. The S3, like the 2019 S5, has 38mm of clearance between the stays. This means a tire that measures a full 30mm wide will meet the generous ISO standards of 4mm of space on either side of the tire.

3/13/19 Note:  Maximum tire size on this bike is controlled by tire diameter more than width.  Except with the widest rims (which flatten tire profile), tires with over 30mm of measured width will likely not have acceptable clearance with the seat tube.

Integrated Aero Drop Bar and Carbon Aero Stem

The second change is that the 2019 S3 receives a new Cervelo AB09 alloy handlebar and matching CS28 carbon stem. This new “shielded” system is the primary reason that there is an aero improvement between the 2018 and 2019 model. Mechanically, the 2019 system is more complex than a non-integrated design, but it has some well thought out features. For example, the very clean lines of the stem and bar shield a “quill style” adjuster that allows for some simple vertical height adjustment.   The bike looks very well thought out clean and we think that the bar/stem package will prove one of the more functional and easy to work with.

It is worth noting that while some improvements in aerodynamics were made in the fork and headtube integration, the majority of the over 13 watt improvement came from the new integrated front-end. However, if you just want/need something different, like the 2019 Cervelo S5, there is the option to put most any standard bar and stem on the 2019 Cervelo S3.  (2/18/20 Update – To date, the adapter to allow an aftermarket stem on the S3 has not been produced by Cervelo.  It is available for the S5.)

Seatpost

The third change on the 2019 S3 is the new seatpost. The new seatpost is more aero and smaller sized S3 bikes (51cm and below) are slated to ship with a 0 degree version while 54cm and above get a setback version.  We wish that they all shipped with the 0 degree version as that will fit the broadest array of people in our experience, but at least you can buy the other option for your bike if the one that ships doesn’t suit your needs.

Stiffness

The fourth change is that the bottom bracket lateral stiffness has been further improved. The thru-axles that were added to the disc version in the ’18 model had already boosted the headtube stiffness significantly over the non-disc version. Unlike the S5 (which is receiving disc brakes for the first time in 2019), there wasn’t a lot of room for improvement on the S3 in that department.

Finish & Colors

There is a fifth change to the S3 – the finishes. We’re not going to count the finish as a meaningful change as doesn’t change the way the bike ride. This being said, if you are not fond of the ’18 model’s finish, you may like the ’19 colors better. The 2019 Cervelo S3 comes in two colors (black/fluoro and black/red)  and the general consensus is that it is quite a nice looking bike either way.

What hasn’t changed on the 2019 Cervelo S3?

Due to the ride, fit and performance if offers, the 2018 Cervelo S3 was arguably our favorite aero road bike to date. Thankfully, for 2019, Cervelo left the parts of the S3 that worked really well alone.  The 2019 S3 is available in disc and rim brake versions as a frame or with a variety of component groups. The frame geometry on the S3 is the same linear and progressive “race” geometry found on the 2018 model. The ride is still one of the most refined found on an aero road frame today. The aerodynamic profile of the bike is still one of the best in the business.

At the same time, Cervelo hasn’t sat on its laurels.  They have pushed the 2019 S3  forward by adding tire width in particular and continuing to improve the CdA (with a significant 100g plus of improvement over the 2018 model that lacks the integrated stem/bar combo). All in all, the S3 remains one of the very best aero road bikes, regardless of price.

If you are in the market for a race capable bike that does most everything well, and the results of a Rider First Bike Fitting show that the geometry is a good match for you, the 2019 Cervelo S3 remains a great choice. Contact us for more information on the new Cervelo models or to schedule a fitting.

• About the Author

About Ian

From first time riders to Olympians, Ian has helped thousands of athletes achieve their cycling and triathlon goals. Ian develops much of the Fit Werx fitting and analysis protocols and is responsible for technology training and development. He is regarded as one of the industry leaders in bicycle fitting, cycling biomechanics and bicycle geometry and design. He is dedicated to making sure the Fit Werx differences are delivered daily and provides Fit Werx with corporate direction and is responsible for uniting our staff and initiatives.

Find out more about Ian Here