The Mason Definition Chorus is a big fan of all trades, but surprisingly a master of everything. It is the definitive road bike, one that offers a great quality of ride and a geometry that works both at speed and when crossing, whether it crosses the city, the region or even the country. The build quality and finish are also impeccable.
In 2015 I felt that the Mason Definition was the pinnacle of what could be an aluminum alloy road bike and that it also broke boundaries.
Although we can now see performance road machines with tires wider than 25mm, and only with disc brakes, as a rule these days, by 2015 standards it was a leap of faith.
> Buy now: Mason’s Definition Chorus for £ 3,665
The fact that it had a geometry to be able to drive all day, quickly and comfortably, also blurred the lines between the booths of the endurance and racing machine. It could also carry mudguards.
It has had some tweaks over the years, but fortunately Mason has generally taken the route “if it hasn’t broken, don’t fix it.” The original definition used front and rear QR skewers, for example, though only because designer Dom Mason was waiting for the standards of the through-axis to be established, before upgrading to 12mm through-axles.
Other than that, however, very little has changed. While it’s actually quite rare for us to revisit a bike that hasn’t changed seriously since the last time we rode it, the times themselves have changed. When we were offered the heart of definition, I was intrigued to see how I had resisted the passage of time.
With all the advances in aluminum tubes and seven years of competition watching and learning, would you still cut the mustard?
The answer is yes!
The vault
For my first trip in this Definition, I left the estate and went to the back lanes, and immediately found myself in a happy place. This original definition has stuck in my memory as possibly the best running quality of any aluminum alloy frame out there: the conversation about aluminum frames giving a hard ride has been silenced in over the years, and the definition is one of the reasons.
It doesn’t behave the way many alloy bikes do, it’s very comfortable. The way it silences the buzz of the road looks more like titanium or steel, giving a velvety feel, a smoothing at the edges if desired, and never minimizing the feeling of integration between the cyclist and the bike .
And here’s the problem: The key to the Definition is that it really feels like an extension of you.
It feels so balanced on the road, even when the surface is rough (as they often are), and the lack of “mist” leaves the feeling of Definition planted. This, in turn, gives you an extra boost of confidence to push you hard on the bends.
The geometry is also perfect, with a balance of angles and tube lengths that lies towards the end of market resistance. The front is not as sharp as the more competitive race bikes, but it is very close, and the angle of the head a little looser, as well as a wheelbase a few millimeters longer to accept the complete mudguards, means the handling is a little less frantic. It really allows you to drive the Mason quickly over long distances.
I’ve hit over 50 mph many times in the Definition, and it feels exceptionally solid there, flowing through the bends gently. It is easy to reach the summit even on the most technical descents.
The steering tube is relatively short, which helps you get into the drops to lower your center of gravity, although it’s not so short that the drop from the chair to the bar becomes extreme.
There is no problem with the bending of the fork when tilted hard or the frictional speed is turned off before a turn, and the stiffness of the fork legs provides positive top-down feedback. It’s a front that lets you know exactly what the tire does.
The frame is also impressively rigid, which makes the Definition feel agile and sensitive to climbs. It’s not a light whippet, but considering its intentions, it doesn’t sink when you get on it, either on the saddle or when you dance with those pedals.
The same thing happens on the floor. The Mason is great for traveling miles at a decent pace, but if the need arises for a hard effort or a touch of sprint, you won’t be disappointed.
From the promenade point of view, the Mason is just a beautiful place to be. It’s such a capable piece of design that it always feels like the right bike for the job (well, probably not if you’re at a critic’s starting line, but you know what I mean) regardless of your pace or your goal. particular trip.
Frame and fork
The driving quality is excellent, but this is where the Definition really shines. I have met Dom Mason countless times over the years and the only thing I have learned is that he is curious about the details. This is highlighted when you approach the Definition.
The frame is handmade in Italy with triple-point 7000 series aluminum tubes manufactured by Dedacciai, tailor-made to the exact shape and wall thicknesses specified by Mason. It is this conformation that has the greatest impact on the overall quality of the ride, rather than just on the material itself.
The definition uses sizes and shapes ranging from the 1 1/8 inch to 1.5 inch conical head tube and a large section D bottom tube, to a slender, oval top tube. The back triangle incorporates what Mason calls his BoatTail stays.
The seat becomes more tapered as they bend toward the toes, with the curves facing up to find them. Custom bending creates free space for the rotor and clamp, helps reduce chain slapping and allows for some compliance that improves comfort, according to Mason’s website.
As before, a threaded bottom bracket is used, although the diameter of the housing is larger than most with 56 mm. This gives more space to pass the gear wires, cables and brake hose under the BB sheath. It also offers a larger welding area in the bottom tube for maximum strength and stiffness. The housing is then “shrunk” to accept the bearing cups of a standard 68 mm wide threaded bottom bracket.
All cables, cables, and hoses run internally using Mason’s Multiport system, which provides several “plates” to accept any of these three that you are inserting or removing from the frame.
The inlet ports are on the bottom tube, with the front mechanical cable / wire protruding from the back of the lower bracket housing, while the brake hose and the rear mechanical cable / wire protrude from the corresponding base. There is also an internal routing for a dynamo cable.
Welding everywhere is exceptional; a true work of art, with the frame and fork finished in a deep luxury painting work, either with the lens blue found here, the shutter black or the Vela.
The Aperture2 fork is exclusive to Mason and weighs 365 g. The retention of the wheels is in charge of through axles and the F-Stop system of Mason allows to replace the insertions of the axis in case the thread is damaged.
The holes in the mudguard are placed discreetly inside the legs, which means that the stays will need a little drag before placing the protectors, although it is a simple process (I speak for experience).
The clearance of the tires is 32 mm with fenders and 35 mm without, although this ultimately depends on your combination of tires and wheels.
Geometry
The Definition is available in eight sizes, which is an impressive figure given the relatively small scale of production. The smallest frame is 48 cm and the largest is 62 cm with effective upper tube lengths of 519 mm and 601 mm respectively.
This is a 54 cm with an effective top tube of 551.5 mm, a steering tube of 155 mm and a wheelbase of 1,009 mm. At an angle, the head is 71.5 ° and the seat tube is 73.5 °. If you base the size on the stack and range, in this size frame you are looking at 565.5 mm and 383 mm respectively.
Mason offers a detailed geometry table on his website for all sizes and a page on size tips based on various bike models.
Finishing kit
The Definition line is available in a variety of versions, with SRAM, Shimano and Campagnolo offering electronic and mechanical changes, and even 1x in the case of Campag’s Ekar. There’s also a “rolling chassis” option that includes a set of frames and wheels, plus an option just for a set of frames.
We have the Campagnolo Chorus option, and it’s also very impressive. The versions we put together for testing are the most common groups running from Shimano, with most of the rest with SRAM. Unfortunately, very few enter with Campagnolo, although this has changed a bit lately: Italian manufacturers have not suffered the same supply and availability problems as others.
When I started riding in 2000, SRAM had yet to enter the road group market, so some small component manufacturers aside, you were a Shimano cyclist or a Campagnolo. There were a lot of “expert” jokes on both sides of the club. The main truth I remember was that “Shimano wears out, while Campag wears out.”
Since then, I’ve led groups of both brands to the end of their lives, and I’d say they’re actually pretty much the same, but I understand where the saying comes from. Campag changers take a while to sleep, and this is also noticeable here. From the box, the Chorus changes don’t feel as smooth and refined as, say, Shimano’s Ultegra; each takes a little more pressure off the lever and there is more noise as the chain falls or climbs up a sprocket.
However, this doesn’t last long: 500-1000 miles later and the change really starts to happen on its own, requiring less pressure to activate. I also like the defined click of the Chorus shifts (you probably know the chain has moved without having to look around), plus the curved carbon brake caps and levers fit snugly with the natural rest positions of your fingers.
You can also perform several turns at the same time, up or down the cassette.
The connecting rod arms of the carbon adapt to the high quality of the Definition finish, and Campag offers dishes …