Specialized Ruby Pro Disc Di2 review

Serene yet responsive disc-equipped endurance ride

Our rating 
4.5 out of 5 star rating 4.5
USD $6,800.00

Our review

Efficient and smooth-riding with electronic shifting and hydraulic disc brakes, the Ruby is a fabulous endurance bike
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With electronic shifting, hydraulic brakes and plenty of women-specific details, Specialized’s Ruby Pro offers an exciting yet comfortable ride – not to mention a standout feature in its disc brakes, which so far are a rarity in women’s bikes.


The Ruby Pro’s comfort stems from several key areas of the bike’s design: Zertz elastomeric inserts (claimed to reduce road vibration), the type and application of the carbon it’s constructed from, the flexible CG-R (aka ‘cobble gobbler’) seatpost, and the endurance geometry. These all work together with the aim of reducing fatigue and providing a suitably silken ride.

Ride and handling: Smooth, stable and confident

The most visually obvious of those features are those Zertz vibration dampers, placed on the fork legs and seatstays. The Ruby Pro is built with Specialized FACT 9R carbon; while it’s a tad heavier than the 11R variety used in the top-level S-Works Ruby frames, it still provides a smooth ride at a more affordable price.

As an endurance bike, you’d expect nothing less from the Ruby Pro. The bike’s comfort features and endurance geometry helped minimize harsh bumps in the road and left us feeling fresh each time we went out on it. What did surprise us, however, was the Ruby’s agile handling through tight corners and how easily it went up and down hills. The bike’s nimble steering made for exciting descents on twisty mountain roads, and despite the added weight from disc brakes, the Ruby Pro effortlessly bounded up and over steep climbs.

Specialized claims its zertz inserts damp vibration: specialized claims its zertz inserts damp vibration

Specialized’s Zertz inserts help kill road buzz

As mentioned above, the Ruby’s ability to deliver long, pain-free hours in the saddle is boosted thanks to its vibration-reducing CG-R seatpost. Humorously termed the ‘cobble gobbler’, the seatpost – as its name suggests – helps eat up cobble-like bumps in the road.

Shimano’s Ultegra Di2 electronic system needs little introduction and provides reliable, buttery smooth shifting all day long. Going with Ultegra Di2 instead of the top-end Dura-Ace helps keep the price down; there’s no discernible performance tradeoff, with the only penalty being a little added weight.

It’s also worth noting that Ultegra Di2 can accommodate a 32t cassette while Dura-Ace can only take a 28t option. That lower gear option is much appreciated (by your knees, in particular) when you just want to spin, rather than grind, your way up a hill. Speaking of lower gearing, the bike comes with a compact 50/34 crank.

Related reading: What is a compact crank?

Unlike other women’s endurance bikes we’ve tested, the Ruby Pro comes stock with Shimano hydraulic disc brakes, and we were immediately grateful for this feature. The hydraulic disc brakes worked phenomenally on steep descents and tricky hairpin corners, with the mechanism functioning smoothly and powerfully enough that we could use a single finger to apply the anchors with total control. The hydro disc brakes elevated our appreciation for descending – and the fun created by flying down a winding mountain road.

Rim brake wheels are not compatible with disc brake bikes so you may have to replace your current wheel arsenal to use with the ruby pro: rim brake wheels are not compatible with disc brake bikes so you may have to replace your current wheel arsenal to use with the ruby pro

Hydraulic discs mean smooth, powerful braking – at the tip of just one finger

Frame and equipment: details that make a difference

Each size of the Ruby Pro has its own carbon layup design, with the aim of delivering optimized ride quality no matter what the stature of the cyclist. This means the smallest 44cm frame won’t be too stiff, nor the largest 57cm – like our test machine – too flexible.

The Ruby is based on Specialized’s Women’s Endurance Geometry, with a longer wheelbase (1021mm on our size 57cm), a relatively low bottom bracket (drop of 71.5mm) and a tall head tube (19cm) delivering a slightly more upright riding position than a traditional race bike.

An interesting quirk of the Ruby’s spec sheet is that the top-level S-Works model comes equipped with the more expensive Dura-Ace Di2 drivetrain but is only available with rim brakes – to deliver the lightest weight build possible. That said, the Ruby Pro’s disc brakes are more efficient and, in this tester’s opinion, a better brake – and the Pro model we tested weighs in at only 17.8lbs (8.1kg), which we certainly don’t consider hefty.

The bike’s 19cm head tube (size 57) provided a comfortably upright riding position: the bike’s 19cm head tube (size 57) provided a comfortably upright riding position

The bike’s 19cm head tube (size 57) provided a comfortably upright riding position

Indeed, unless you’re one serious weight weenie, we’d advocate opting for the Pro model over the S-Works. It offers a wider gear range and the hydraulic disc brakes are simply more effective. Sure, you add a little heft, but your wallet will remain heavier as well.

Staying on the subject of weight, the Ruby Pro comes with the light and responsive Roval Rapide CL 40 SCS Disc wheels, which are suitable for all kinds of riding. These versatile hoops can easily pull double duty as training and race wheels, and they performed well under testing on both long endurance rides and technical road races.

Unfortunately, we were less fortunate with the Specialized Turbo Pro 25mm tires. Within out first few rides, we experienced multiple flats and eventually chose to switch to more durable rubber. As with all punctures, luck and road conditions played their part, and we were testing the Ruby this spring when the Colorado roads were sandy and full of debris collected throughout the winter. That said, while we won’t blame the Turbos for all our flats, we also didn’t experience any more once we’d swapped them out. We’d have also preferred the Ruby to come with stock 28mm treads for added cushioning and pinch flat resistance.

Small details scattered throughout the bike help make all the difference to the Ruby Pro’s character. Over the years, we’ve had great luck with Specialized BG (Body Geometry) women’s-specific products.

As we’ve mentioned in other reviews, no one saddle can fit every woman. To combat this problem, Specialized offers seats in three different widths to accommodate more body shapes and sizes. The Ruby Pro comes with with the women’s Ruby saddle, which has been one of our go-to perches for years.

Specialized’s ruby saddle is one of our favorite saddles and it worked well with the ruby pro endurance bike: specialized’s ruby saddle is one of our favorite saddles and it worked well with the ruby pro endurance bike

The Ruby saddle comes in three widths

The Ruby also comes with Specialized Women’s Expert shallow drop handlebar. Women typically have smaller hands than men and the shallow drop of this bar made a big difference. We felt comfortable and in control when riding in the drops and we also found it easier to reach the brake and shift levers.

Another nice detail is the Pro SL stem with a custom mount for the bike’s Di2 junction box. This mounting system uses the stem bolts to cleanly keep the junction box in place without using Shimano’s antiquated rubber bands to hook it all together. 


Unlike the other women’s endurance bikes we have tested, the Ruby Pro includes fender mounts for anyone who regularly rides in foul weather or just wants to be prepared for sudden downpours. These mounts are small and easily overlooked but we really appreciated this attention to detail and additional versatility.

Product Specifications


Name Ruby Pro Disc Di2
Brand Specialized

Brakes Shimano 785, hydraulic disc
Shifters Shimano 785 Di2
Wheelbase (cm) 102.1
Top Tube (cm) 56.6
Seat Tube (cm) 48.6
Chainstays (cm) 41.7
Brake Levers Shimano 785 Di2
Weight (lb) 17.8
Chainring Size (No of Teeth) 34 50
Year 2015
Wheelset Roval Rapide CL 40 SCS Disc Carbon Clinchers
Weight (kg) 8.07
Trail 5.9
Stem Specialized Pro SL, alloy
Seatpost CG-R
Cassette Shimano Ultegra, 11-speed, 11-32
Seat Angle 73.5
Saddle Body Geometry Women's Ruby Expert, hollow Ti rails, 155mm
Rear Tyre Size 700x25
Rear Tyre Specialized Turbo Pro, 127TPI, folding bead, BlackBelt protection
Rear Derailleur Shimano Ultegra Di2
Head Angle 72
Handlebar Specialized Women's Expert, shallow drop, alloy, 123mm drop, 75mm reach
Front Tyre Size 700x25
Front Tyre Specialized Turbo Pro, 127TPI, folding bead, BlackBelt protection
Front Derailleur Shimano Ultegra Di2
Fork Specialized FACT carbon, size-specific taper
Cranks Specialized Pro FACT carbon
Chain Shimano Ultegra, 11-speed
Frame size tested 57cm