It was a good day back in March when Shimano called and offered to provide us with a new 12-speed Dura-Ace component group. All we needed to do was find a frame to hang the parts on. Turns out that wasn’t as easy as we thought it would be. After trying a few different American frame vendors, we came up empty-handed. Owing to the pandemic-fueled shortage of everything, it seemed no one could spare a frame for the build within the timeline needed. Hmmm.
Well, we figured, if we can’t find a frame at home, why not head over to our favorite home away from home to try our luck? And so, we called our friends at Basso, who maintain a small, family run factory in Italy, and asked if they had a frame they could spare for a project bike.
What we received is a striking Diamante SV disc that has seen a few improvements since we last tested the rim-brake version (RBA, September 2018). The aero-inspired road bike remains aggressive and race-oriented, but now with integrated hoses and cables or, in our case, two wires. The frameset still utilizes the unique 3B triple-point seat clamp and rubber gusset to secure the seatpost. This unique retention system is to add a level of compliance to an otherwise stiff race platform.
The aero-optimized and integrated fork/frame design allows the headset to sit below the top tube, allowing for a stiffer front end. Our 53cm test bike has a top-tube length of 54.5cm and a head tube of 13.7cm. The short 98.9 wheelbase and 72.3-degree head tube make this a bike that is quick to respond and lively. There is a 39cm frame reach with a stack of 54cm for a long and compact fit. The carbon frame is hand-laminated and still made in a factory located near Vicenza, Italy.
Not to shadow the stunning craftsmanship of the Basso, our bike is the parts mule for the all-new Shimano Dura-Ace R9200 drivetrain. The latest release from Shimano is Di2-specific and uses a new wireless hybrid connection system.
Beyond the new drivetrain is also a new Pro Stealth Curved saddle that is narrower and has oversized carbon rails. Pro also swapped the integrated Basso bars/stem combo out for their new one-piece Vibe Evo. For wheels, the deep purple Basso rolled on the new Dura-Ace C50 wheels that now have a modern 21mm internal width. The rims are tubeless-ready and still use a hook bead for those that are not all in on tubeless yet. The wheels were wrapped with 28mm Vittoria Corsa Graphene 2.0 tires.
The subtle changes that have been made to the Diamante have not changed its ride characteristics. The bike retains race-oriented handling and razor-sharp responsiveness. This bike is like an attack dog that sits leashed just waiting for you to cut the lead. The bike truly performs best under a confident rider that is willing to push the envelope. Rider input gets a lively response.
For us, it always takes a few rides to adapt to a bike with this type of hyper-responsive handling, as it is something that many of the big brands have moved away from as they target easier-to-handle bikes to attract the masses.
Not surprisingly, the new Dura-Ace drivetrain is amazing, but the true stand-out was the feel and performance of the brakes. On a bike like the Basso, you can push the limits of every corner as the new Servo-Wave brake actuation provided improved feel and modulation. On previous Shimano road disc brakes, there was almost an on/off feel, but now the brake’s progression is much improved.
As always, the Di2 shifting is spot-on and fast. Shimano claims faster shifting because of the cog spacing with 12 gears, but for us it was hard to validate since it has always been lightning fast and accurate. The new C50 wheels matched to the stiff Diamante frame means that accelerations have no delay, and the wider internal width added a bit of air volume to the Vittoria tires. Despite running inner tubes, the road feel of the Vittoria tires was amazing, although we’ve found it often comes at the cost of a bit of durability. Since they are 28mm on a 21mm internal width, we ran around 70 psi since tubes do reduce the volume slightly compared to tubeless.
With each new ride we came away admiring the Diamante more and more. The new Shimano Dura-Ace 12-speed is amazing and shifts fantastic, but the brakes are the true standout. The wireless technology that Shimano offers is great but doesn’t seem to add or subtract from the user experience other than no wires are on display up front. The Pro Vibe Evo bar is big and not the perfect match for the internally routed Basso. Because of this, the brake hoses are exposed near the stem, but the stock bar system would keep this completely hidden.
The pro-level geometry and stiffness are not for the less experienced rider, but lots of fun for those that push the limits. Basso’s production originated in Italy for over 40 years ago, so you know you’re getting a bike that is special. Shimano has made some big changes, and best of all the user experience is almost unchanged. Improved brake feel is a perfect match to a performance bike like the Diamante.
• A true race bike
• Italian-made, Italian styling
• Updated integration
Price: $6450 frameset
Weight: 16.37 pounds
Sizes: 45, 48, 51, 53 (tested), 56, 58, 61cm