Ribble has today unveiled a brand new aero racer, the Ribble Ultra SL R. At a first glance you could be forgiven for thinking that the Ultra represents the usual fare of aero bikes – wide kammtail tubes, dropped seat stays and integrated cabling, but up close there is a lot of fresh thinking around the Ultra.
Andy Smallwood, CEO of Ribble, met Rouleur ahead of the Ultra’s launch to talk through some of the bike’s innovations, and offered us a close look at the flagship Ultra SL R Hero build. Pulling up a flurry of Computational Fluid Dynamic diagrams and wind tunnel data, Smallwood left us with no illusions that Ribble’s Ultra has been through extensive design and testing to get to its finished state.
While that may seem run of the mill for a major bike manufacturer, it’s worth remembering that only five years ago or so Ribble was a brand that was often regarded as a direct-to-market seller of generic Far Eastern frames, parts and accessories, rather than a bike maker in the truest sense.
In 2018, under new management, Ribble launched 23 completely new bikes at the Cycle Show to a pleasantly surprised bike market. That was the beginning of a statement of intent to design and assemble bikes in the UK, which today seems to have taken on the next phase of Ribble’s journey, as a leading bike designer.
So, let’s delve into the detail of the Ultra’s disruptive design.
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Airfoil design
The first feature to stand out in any aerodynamic bike design tends to be the tube shapes — and that's no exception with the Ultra, which Ribble initially named the "bat bike" during its design on account of its dramatic tube shapes and curves.
“So we started off with a traditional airfoil and then truncated it,” says Smallwood. “We started looking at the shape of the airfoil and started moving the chord [which Ribble use to describe the bulge of the tube shape] backwards and forwards to start to understand what happens to the airflow, particularly at different YAW [wind] angles, when you start to adjust the chord of the airfoil.”
Alongside that, Ribble experimented with the width of the truncated rear edge. With Smallwood and Head of Product (and wind-tunnel mannequin) Jamie Burrow leading the design process, Ribble ran all of these simulations through CFD before verifying them in the wind tunnel. Ribble used the Silverstone Sports Engineering Hub wind tunnel, and quickly found considerable aerodynamic gains compared to the previous generation aero road bike, the Endurance SL R.
Designing to a YAW range (the range of angles at which the bike will face the main airflow) of +/- 20°, the Ultra reflects design for real world conditions in a range of settings. In many cases, the bike has been designed to be faster at middling YAW angles, as straight on 0° is relatively rare in outdoor riding. The truncated headtube shape, for instance, saw the most effective aerodynamic results at a YAW angle of 10°.
Ribble details many of these design concepts and tests in its 20-page white paper on the bike’s development.
In a similar vein, there have been concessions for practical day to day riding. For instance the, considerably chunky, downtube has been designed around a bottle being mounted. The large flat central part of the lower section of the tube is designed to shield a normal round bottle from airflow throughout the bike’s projected YAW angles.
Those various tube shapes, when put together, made for considerable overall gains.
Ribble claims the Ribble Ultra SL R – compared to the Endurance SL R used by UCI continental teams such as Drops Le Col and Ribble Weldtite – offers a 75.1 second saving over 40km at 22mph across the average of 5 and 10 degrees of YAW. That goes down to 61.4seconds over the same 40km distance when travelling at 29mph. Over a 100km ride that makes for a significant 3-minute saving.
But, while it’s easy to fixate on tube shapes when considering aerodynamic design, it’s the more minor details where Ribble has arguably made the most significant gains – namely around the handlebar and cockpit.
Ultra Aero handlebar
“The handlebar is the first thing that hits the air,” says Smallwood, “So we decided we should be spending quite a lot of our time looking at the handlebar — there is a lot of interaction between handlebar and rider.
“We found that what stopped us from making the handlebar any shape we wanted was the clamp. On every single handlebar for a road bike you have to have this metal band that goes around a handlebar, it has to be 23.8mm in diameter and it's got to be round. That dictates the shape of the handlebar.”
Working around the problem, Ribble has developed an adjustable lever plate to sit on the front of the bars, to which the lever hood bolts onto. It’s a first in mass manufactured bike design, and Ribble currently has a patent pending for it.
By removing the design constraints of the round drops, the Ribble Ultra bar takes on a hugely (and somewhat jarringly) aerodynamic profile. It is mildly splayed but boasts wide and ergonomic drops with a thin taper at the centre of the curve to help improve comfort and introduce some engineered flex.
The tops (which, admittedly, could boast the same profile without the patented lever clamp design) are reminiscent of Cervelo’s 2015 S5 handlebar design, with a wide and bulky flat section that should prove comfortable on rougher terrain given the greater contact area. Naturally, all cabling is completely internal so the front of the bike is extremely neat and clean in terms of airflow. Ribble's testing shows that this shape on the top bar is designed to maximise its interaction with the rider, and makes for considerable aerodynamic gains.
We’d have to spend more time with the bike to determine if the bar shape leads to niggles of wrist strikes or any ergonomic irritation. On first impressions the bar seemed to offer an ergonomic finish and comfortable grip.
Many mechanics may look on with mild horror at Ribble violating the sanctity of that most holy of round handlebar and lever clamp union. But I’m left wondering – why on earth were we bothering with circular metal clamps? It may seem like a small innovation but it’s one that brings to mind past game-changing developments in aero bikes such as Trek’s IsoSpeed seatpost on the 2015 redesign of the Trek Madone. As the first point of contact with the air, the handlebar plays a big role in aerodynamics, and so opening up its design parameters not only offers considerable gains today but promising future opportunities.
“It's been ergonomically designed to use without bar tape,” Smallwood adds. For those fans of the perfect bar tape wrapping technique, that may be tough to stomach. However, as carbon doesn’t have the cold touch of an alloy bar, the feel of the bars isn’t that alien — helped by the slightly wider diameter of the bar. For fear of slippage, I may personally opt for a few roles of bar tape at the end of the drop, in track-bike style, but the grip seems to be fairly firm while the naked bar could become more aesthetically normal over time.
Clearing the air
While there are dozens of design tweaks we could hone in on, we were really drawn to the Ultra’s forks. These showcase an ultra wide set of forks that seem to almost pay homage to the Lotus x Hope British Cycling track bike.
“What we found is quite interesting, backing up what Hope and British Cycling have done with the Lotus x Hope track bike. Head-on, we saw a big benefit from pushing the fork legs out,” says Smallwood. “The benefit comes because the fork is actually in front of the leg,” says Smallwood.
Shop Ribble Ultra SL from £3,199
“But as soon as we move to a wider angle of YAW, away from a headwind, you end up having a negative impact from having the fork outbound. So, we settled on a very specific shape with a specific width and length. That was to not only shield the legs, but we also aligned the fork blade with the rear seat stays as well. So the seat stays are moving the shadow with the fork blades.”
That wide stance of the forks has the double benefit of wide tyre clearances – there’s ample clearance for 32mm tyres, and the Ultra comes specced with 28mm Continental Tyres as standard.
At 68mm in depth and 15mm in width, the Ultra’s forks cut a deep blade-like shape, also helping shield the disc brakes from wind — with the disc rotor sitting inside the front forks. The bulky shape adds to our surprise that the entire bike comes in at only 7.6kgs in a size medium. Our Ultra Hero build was palpably light considering its pure bulk.
The SL R frame itself comes in at just 1,050g in a size medium.
While the Ultra SL R Hero tops the range at £7,299, the range begins at £3,199 for the entry-level Ultra SL build.
“On the SL frame we have the same platform with a slightly different carbon layup – so it's a bit heavier. It's 250g more than the SL R for the complete frame and fork," explains Smallwood. “That spec comes with our Level Five finishing kit. When you go up into the SL R frame you get the Ultra Aero Handlebar across all the models. They all come with deep-section carbon wheels.”
Unsurprisingly, Ribble has also developed a triathlon-specific version, as we don’t doubt that the platform will appeal to triathletes as much as road racers.
The Ultra SL R will begin at £4,199, while the Ultra SL will start at £3,199. The earliest delivery times across the range appear to be November, with some models stretching out into a projected 2022 delivery.
We hope to get our hands on a review sample in the next few months, and so watch this space for a more in-depth look at the Ribble Ultra.
