It’s been an open secret for a while now, but the new CeramicSpeed OSPW Aero jockey wheel set has now been officially launched.
We spotted the OSPW Aero on the Factor Ostro VAM of Israel-Premier Tech’s Giacomo Nizzolo at the Giro d’Italia in May and CeramicSpeed says that it’s also been used in anger at the Ironman World Championships.
As we reported at the time, the CeramicSpeed OSPW Aero has been developed in collaboration with aerodynamicist Simon Smart at Drag2Zero, whose initials also grace the recently launched Enve SES 4.5 wheels.
CeramicSpeed says that it’s taken over two years of development to bring the OSPW Aero system to market. It claims that the final product reduces local drag around the derailleur by 40 per cent on average and at some points in the airflow by up to 60 per cent, relative to a standard derailleur cage.
According to the brand, that translates to 2.5 seconds trimmed off the time for a 25km time trial ridden at 50km/h or 1 minute 15 seconds for an Ironman bike leg ridden at 30km/h. That may sound like the most marginal of gains, but those small increments are CeramicSpeed’s specialism.
Wind tunnel and real world testing
The OSPW Aero is the result of extensive wind tunnel and real-world testing. Since the derailleur cage moves relative to the bike frame as the rider shifts gears, its angle - and so its frontal area - changes. This means the cage has to perform aerodynamically in different positions relative to the airflow.
Wind tunnel tests were performed using Canyon and Scott time trial bikes and Factor, Specialized and Scott aero road bikes. They also included a disc rear wheel as well as a 60mm deep, spoked aero one. CeramicSpeed says that it wasn’t able to simulate the fluctuating airstream wake from a pedalling rider effectively though.
CeramicSpeed says that it’s also tested both in the wind tunnel and outdoors at different crosswind yaw angles. There’s a more comprehensive description of the test protocol and analysis of the results on CeramicSpeed’s site (opens in new tab).
Smart says that the development has been complex: “Given that this only represents about one per cent of the total system drag, we knew that we had a challenge on our hands particularly as the rear derailleur cage sits on the most complicated area of flow on the bike, and also given the position and angle changes. This is one of the most complex areas of the bike to develop,” he points out.
Smart says that they tested alternative pulley set-ups, but these reduced the mechanical efficiency of CeramicSpeed’s original OSPW design, so the new OSPW Aero retains that system’s pulley layout. Keeping weight down while retaining stiffness for precise gear changes was also a challenge, says Smart.
When we first spotted the new system, questions were raised whether the new OSPW Aero would fall foul of the UCI’s regs banning fairings, but the aero cage design is structural and integral to the system. CeramicSpeed says that it’s discussed the design with the UCI and gained its agreement that it doesn’t contravene the regulation governing fairings.
The derailleur cage itself is made of carbon fibre reinforced polyamide. As with the standard OSPW system, there’s a 19-tooth lower pulley and 13-tooth upper pulley (15 teeth on SRAM-compatible models), both made of aluminium. They come with CeramicSpeed’s metallic-coated bearings, designed to up longevity, with CeramicSpeed offering a lifetime warranty.
Options and prices
There are three options for the OSPW Aero, giving compatibility with Shimano 9250/8150 12-speed, Shimano 9100/8000 11-speed and SRAM Red/Force eTap AXS groupsets. Availability is from 21 June 2022 and the price for all options is €739 from CeramicSpeed’s own website.
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Paul has been on two wheels since he was in his teens and he's spent much of the time since writing about bikes and the associated tech. He's a road cyclist at heart but his adventurous curiosity means Paul has been riding gravel since well before it was cool, adapting his cyclo-cross bike to ride all-day off-road epics and putting road kit to the ultimate test along the way.