I was recently given the opportunity to review the Cervelo S3 Disc; an incredibly fast, fast bike with razor-sharp handling. So I did the obvious thing and put it to the test by riding it from Lands End to John O’Groats.
Over nine days I would ride 969 miles, pedal twice the height of Everest, and tick off 23 counties and three countries, in torrential rain, hail storms, and freezing temperatures.
The perfect way to test out an aero road bike.
Canadian brand Cervelo has long been at the forefront of aerodynamics, and the S3 traces its lineage back to the Cervélo Soloist, a machine regarded as a pioneer in aero road bike design.
One of the things that stood out almost immediately is that Cervelo hadn’t just slapped on a set of disc brakes and called it a day.
Instead Cervélo has reimagined the frame to smooth out any penalties that might occur from adding disc brakes, and created a bike that is better than the rim-brake version in pretty much every way.
Speaking about the S3 Disc, Cervelo explained that its policy is to 'only introduce a new bike when significant gains in design and technology have been achieved.
'Therefore the newest disc model had to equal or surpass the S3 in all five of the performance criteria encompassed by our Engineering Fundamentals: Weight, stiffness, ride quality, usability and most importantly, aerodynamics.'
According to Cervelo the frame is 9% stiffer, has a net reduction in drag of a claimed 2W, and is 40g lighter than the regular rim brake model.
Okay so unless you're the type of person who pores over weight weenies, these numbers seem small, but it is pretty incredible to see a disc bike that is lighter, stiffer and more aero than the rim brake equivalent.
There are the now standard 12mm thru-axles at the fork and rear dropouts, coupled with flat mount disc brake calipers.
The switch from quick release to 12mm thru-axles has, unsurprisingly, resulted in more stiffness.
Cervelo says there's an 8% increase in head tube stiffness and 9% bottom bracket stiffness which improves overall handling and power transfer to the pedals.
Introducing disc brakes also increased tyre clearance, and while the bike is specced with 23mm, I popped some 25mm Continental GP 4 Seasons tyres on for my ride with ease.
The trend is obviously to go with bigger tyres these days, but ultimately this is meant to be a race bike where 25mm is still the current standard.
Cables are internally routed to reduce drag, and the hydraulic disc brake hoses are nicely hidden inside the fork and frame, although I did find they caused a bit of a rattle.
Because of aero seat tube, the Di2 battery is concealed inside the down tube.
The crankset is a carbon fibre FSA SLK 52/36t specially adapted with a 5mm offset to provide the correct chainline with the S3 Disc's short 405mm chainstays.
I took this off for my ride and replaced with my Quarq power meter with no issues.
When I first took the bike out for a little test, I couldn’t help but get excited by the incredible responsiveness and pure speed of it.
Acceleration came effortlessly in a way that only comes from the stiffest most aero road bikes. It was incredibly stable at high speed even when I was facing the gusty conditions of the Scottish Highlands.
Being an aero bike, the position is quite aggressive and head down, so I had been a bit worried about doing an endurance ride on it but was able to comfortably tackle 100 miles plus a day on it.
That said if you are looking for an endurance bike to take in the views from, this is probably not the bike for you.
In Scotland, the road surface could be a bit patchy in parts, and at times the ride could be a bit jarring. However I have to admit from a bike as stiff as this, I was expecting it to be much worse.
At the end of the day, it is a race bike through and through, and not meant for long steady days in the saddle.
Ultimately if you are looking for a fast, responsive bike with the reassurance of disc brakes, the Cervelo S3 Disc is a fantastic option.
Distributor
Verdict
Ultimately if you are looking for a fast, responsive bike with the reassurance of disc brakes, the Cervélo S3 Disc is a fantastic option. We just need British Cycling to let disc brakes into the amateur peloton now.
Cervélo launches S3 Disc
Cervélo is a brand that has long prided itself on its aerodynamics and general technology-driven outlook, and that's certainly evident here with the launch of a disc-braked version of its aero road bike, the S3.
The new S3 Disc has a frame that is a claimed 40g lighter than the rim-brake version, with an 8% increase in head tube stiffness and a 9% increase in the bottom bracket stiffness. At a yaw angle of 15° the new bike saves a claimed 19 grams of drag, which Cervélo reckons translates to roughly around 2 watts.
There are three models of the S3 Disc available, defined by their associated groupsets: Shimano Ultegra, Ultegra Di2 or SRAM Red eTap, which retail at £4,249, £6,199 and £7,649 respectively. Each come with hydraulic braking systems from either FSA or SRAM, and an aero wheelset from either HED or Enve. The bikes also come kitted out with the new aero-friendly AB04 handlebar and SP17 seatpost too.
A commonality between the models is the use of thru-axles, as is the use of flatmount callipers, with Cervélo adopting two cemented standards for disc-braked bikes. Regular Cervélo technologies such as BBRight, whereby the non-drive side of the bottom bracket shell is made wider (and therefore stiffer) and a partial seat tube cut out for aerodynamics, remain present across the range - but there's also some updates.
The fork is a claimed 19g faster than the standard S3 model thanks to an updated leg design with a more efficient airfoil shape. In the absence of rim brake necessities, the fork crotch has been raised too, which minimises the area of low pressure behind the crown,and the seat and chain stays have also been updated with lessons learned from the R3 Disc, making for a proposed stiffer back end.
More to come when we get our hands on one for a review.
