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Mavic unveils Cosmic CXR 80 aero wheels

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After already being raced for about a year under the Garmin-Barracuda team, Mavic finally announced the release of the new Cosmic CXR 80 aero wheels. According to Mavic's testing at the wind tunnel in Geneva - which we were on hand to witness - the new Cosmic CXR 80s produce substantially lower drag than Zipp's 808 Firecrest

After already being raced for about a year under the Garmin-Barracuda team, Mavic finally announced the release of the new Cosmic CXR 80 aero wheels. According to Mavic's testing at the wind tunnel in Geneva - which we were on hand to witness - the new Cosmic CXR 80s produce substantially lower drag than Zipp's 808 Firecrest (Image credit: Jonny Irick)
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Garmin-Barracuda sports scientist Robby Ketchell worked with Mavic to help develop the new Cosmic CXR 80. Team riders have been testing the new wheels for about a year

Garmin-Barracuda sports scientist Robby Ketchell worked with Mavic to help develop the new Cosmic CXR 80. Team riders have been testing the new wheels for about a year (Image credit: Jonny Irick)
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Mavic tested and developed the new Cosmic CXR 80 wheels at the Hepia wind tunnel in Geneva, Switzerland

Mavic tested and developed the new Cosmic CXR 80 wheels at the Hepia wind tunnel in Geneva, Switzerland (Image credit: Jonny Irick)
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The Geneva wind tunnel occupies a unique setting beneath a bridge that spans the Rhone River

The Geneva wind tunnel occupies a unique setting beneath a bridge that spans the Rhone River (Image credit: Jonny Irick)
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This space was once intended for train tracks

This space was once intended for train tracks (Image credit: Jonny Irick)
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The Geneva wind tunnel is literally built inside the side of a hill, occupying space that was once intended to be a tunnel for a train

The Geneva wind tunnel is literally built inside the side of a hill, occupying space that was once intended to be a tunnel for a train (Image credit: Jonny Irick)
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The wind tunnel that Mavic uses in Geneva, Switzerland, also tests a wide range of other equipment including Formula 1 cars, airplanes, and just about anything else that will fit inside the chamber. For example, these wings were used by Swiss daredevil "Jetman" Yves Rossy to cross the Grand Canyon back in May 2011. The single gram resolution of the wind tunnel has even allowed drag measurement of watch hands for a Swiss company - for improved long-term accuracy, of course

The wind tunnel that Mavic uses in Geneva, Switzerland, also tests a wide range of other equipment including Formula 1 cars, airplanes, and just about anything else that will fit inside the chamber. For example, these wings were used by Swiss daredevil "Jetman" Yves Rossy to cross the Grand Canyon back in May 2011. The single gram resolution of the wind tunnel has even allowed drag measurement of watch hands for a Swiss company - for improved long-term accuracy, of course (Image credit: Jonny Irick)
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Ever wondered about the aerodynamics of a squirrel suit?

Ever wondered about the aerodynamics of a squirrel suit? (Image credit: Jonny Irick)
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The wind tunnel was only made possible by virtue of an abandoned civil works project. Back in the 1920s, a tunnel was partially dug to run train tracks below the road surface of this bridge but that plan was scrapped. The wind tunnel now occupies the leftover void and thus enjoys constant environmental conditions around the clock - and year-round - thanks to the considerable thermal mass of the surrounding mountain

The wind tunnel was only made possible by virtue of an abandoned civil works project. Back in the 1920s, a tunnel was partially dug to run train tracks below the road surface of this bridge but that plan was scrapped. The wind tunnel now occupies the leftover void and thus enjoys constant environmental conditions around the clock - and year-round - thanks to the considerable thermal mass of the surrounding mountain (Image credit: Jonny Irick)
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Flavio Noca is the aerodynamics master engineer at the wind tunnel facility in Geneva, Switzerland

Flavio Noca is the aerodynamics master engineer at the wind tunnel facility in Geneva, Switzerland (Image credit: Jonny Irick)
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Mavic developed this tool to measure real-world relative wind direction while riding. That information is also correlated to wheel rotational speed

Mavic developed this tool to measure real-world relative wind direction while riding. That information is also correlated to wheel rotational speed (Image credit: Jonny Irick)
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Plugs at the back of the vane tool connect to a sensor at the front wheel to measure rotational speed and a computer to download the stored data

Plugs at the back of the vane tool connect to a sensor at the front wheel to measure rotational speed and a computer to download the stored data (Image credit: Jonny Irick)
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Mavic product manager Maxime Brunard presents the new Cosmic CXR 80 wheels

Mavic product manager Maxime Brunard presents the new Cosmic CXR 80 wheels (Image credit: Jonny Irick)
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We were bystanders in Geneva, Switzerland, while technicians tested various setups in the wind tunnel. With seemingly no funny business at work here, the new Mavic Cosmic CXR 80 wheels displayed dramatically lower drag than Zipp's 808 Firecrest wheels past about nine degrees of yaw. Stall angle without the blades installed is an impressive 13.5 degrees or so while adding them pushes that out another 1.25 degrees

We were bystanders in Geneva, Switzerland, while technicians tested various setups in the wind tunnel. With seemingly no funny business at work here, the new Mavic Cosmic CXR 80 wheels displayed dramatically lower drag than Zipp's 808 Firecrest wheels past about nine degrees of yaw. Stall angle without the blades installed is an impressive 13.5 degrees or so while adding them pushes that out another 1.25 degrees (Image credit: Jonny Irick)
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Mavic say the new CX01 moniker doesn’t apply just to a single component but rather how the wheel and tire combination are designed to work together

Mavic say the new CX01 moniker doesn’t apply just to a single component but rather how the wheel and tire combination are designed to work together (Image credit: Jonny Irick)
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When installed, the 'blades' dramatically smooth the transition between the tire and rim. Overall drag measurements at lower yaw angles doesn't change much with or without the blades installed but the stall angle increases by a few degrees when they're in place

When installed, the 'blades' dramatically smooth the transition between the tire and rim. Overall drag measurements at lower yaw angles doesn't change much with or without the blades installed but the stall angle increases by a few degrees when they're in place (Image credit: Jonny Irick)
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The blades weigh virtually nothing and are extremely simple to install, securely snapping into a pronounced channel in the rim

The blades weigh virtually nothing and are extremely simple to install, securely snapping into a pronounced channel in the rim (Image credit: Jonny Irick)
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Mavic say the cross-sectional profile of the new Cosmic CXR 80 wheel and tire system adheres to a NACA 0024 airfoil. The rim measures 27mm across right at the tire but the maximum rim width is 28mm

Mavic say the cross-sectional profile of the new Cosmic CXR 80 wheel and tire system adheres to a NACA 0024 airfoil. The rim measures 27mm across right at the tire but the maximum rim width is 28mm (Image credit: Jonny Irick)
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Mavic say the cross-section of the leading side of the new Cosmic CXR 80 wheel-and-tire system replicates a NACA 0024 airfoil profile while the trailing side reproduces a truncated NACA 0011 shape

Mavic say the cross-section of the leading side of the new Cosmic CXR 80 wheel-and-tire system replicates a NACA 0024 airfoil profile while the trailing side reproduces a truncated NACA 0011 shape (Image credit: Jonny Irick)
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According to Mavic product manager Maxime Brunard, narrower front hub flanges yielded better wind tunnel numbers but the final result produced a better compromise of speed, bearing performance, and wheel stiffness

According to Mavic product manager Maxime Brunard, narrower front hub flanges yielded better wind tunnel numbers but the final result produced a better compromise of speed, bearing performance, and wheel stiffness (Image credit: Jonny Irick)
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The rear hub uses differential spoke flange diameters and a carbon-fiber center section

The rear hub uses differential spoke flange diameters and a carbon-fiber center section (Image credit: Jonny Irick)
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Mavic also say that wind tunnel data pointed to internal nipples but the difference wasn't enough to offset their inconvenience if truing was required after a tire was installed

Mavic also say that wind tunnel data pointed to internal nipples but the difference wasn't enough to offset their inconvenience if truing was required after a tire was installed (Image credit: Jonny Irick)
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The matching Mavic Yksion CXR tubular tires feature a very slightly modified casing profile to more closely approximate the desired airfoil profile of the tire-and-rim combination but it's still very close to round so there should be very minimal effect on handling characteristics

The matching Mavic Yksion CXR tubular tires feature a very slightly modified casing profile to more closely approximate the desired airfoil profile of the tire-and-rim combination but it's still very close to round so there should be very minimal effect on handling characteristics (Image credit: Jonny Irick)
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The tread on the new Mavic Yksion CXR tires are said to improve air's ability to 'stick' to the surface and then smoothly transition back along the rim

The tread on the new Mavic Yksion CXR tires are said to improve air's ability to 'stick' to the surface and then smoothly transition back along the rim (Image credit: Jonny Irick)
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Mavic claims to have logged eight separate sessions in the Geneva, Switzerland wind tunnel to fine tune the Cosmic CXR 80, totalling over 400 hours and more than 160 different test configurations

Mavic claims to have logged eight separate sessions in the Geneva, Switzerland wind tunnel to fine tune the Cosmic CXR 80, totalling over 400 hours and more than 160 different test configurations (Image credit: Jonny Irick)
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Mavic used their special on-bike wind direction meter to generate a real-world plot of wind angles vs. frequency

Mavic used their special on-bike wind direction meter to generate a real-world plot of wind angles vs. frequency (Image credit: Jonny Irick)

This article originally published on BikeRadar

Mavic on Sunday launched a wheel the company is calling the “most aerodynamic in the world,” with a uniquely integrated tire system called CX01 (pronounced "see ex one").

The new Cosmic CXR 80 has a novel 80mm-tall rim profile featuring channels for plastic 'blades' that snap into place and dramatically smooth the transition between wheel and tire. Garmin-Barracuda raced the wheels to victory in last year's Tour de France team time trial. Mavic claims this wheelset is so fast that it will unseat the current benchmark of aero speed, the Zipp 808 Firecrest.

Not just a wide profile

It should come as no surprise that Mavic's new Cosmic CXR 80 carbon tubular rim is wide, measuring a generous 27mm across at the tire bed, with a maximum width of 28mm about a third of the way down the profile. However, it's how that profile is integrated with the matching tire that produces the impressive wind tunnel figures.

About 4mm of that width at the tire bed is dedicated to a channel on either side for the new CX01 'blades' – nearly weightless plastic strips that snap into place to produce a smooth transition between the tire sidewall and rim. When combined with the slightly altered casing profile and special tread texture of the matching Yksion CXR tire, the result is a NACA 0024 airfoil profile on the leading side of the wheel and a truncated NACA 0011 airfoil one on the trailing side.

Mavic's wind-tunnel data suggests modest aerodynamic gains over a Zipp 808 Firecrest at yaw angles up to about 10 degrees. However, Mavic's data also suggests that the 808 begins to stall out at that angle while the drag for the Cosmic CXR 80 continues to drop. When the Cosmic begins to stall at 18 degrees – and where the difference is most dramatic – Mavic claims a 6.4W energy savings at 50km/h (31mph), which translates to 15 seconds saved over a 40km time trial or a more substantial 1' 10" for a full Ironman leg.

Compared to Mavic's Ksyrium, the advantages are even more dramatic: 20 watts, 49 seconds, and more than four minutes for the same conditions.

Attention has to be paid to those novel 'blades’ that smooth the transition between tire and wheel. Garmin-Barracuda used them for a bit last season — until the UCI at least temporarily banned them, pending further investigation. Mavic's tunnel data suggests that the blades' biggest effect is on stall angle, which drops to about 14 degrees when they're removed. Up until that point, however, the blades don’t have a huge influence.

So does this mean the Cosmic CXR 80 is really faster than the Zipp 808? Well, yes and no. Mavic's wind tunnel data reveals only a modest advantage over the Zipp up to 10 degrees of yaw. However, the divergence of the two curves past that point suggests that the new Cosmic is faster over a wider range of conditions, plus the gentler upswing hints to more predictable handling in swirling wind.

Aerodynamic benefits aside, the new Cosmic CXR 80 looks to be a capable wheelset in other key performance areas. Total claimed weight without tires is a respectable 1,630g (725g front; 905g rear; 2,170g with tires and blades) so they're still useful on moderately hilly courses. In addition, the sleek carbon-bodied hubs feature reasonably wide aluminum flange spacing for good overall stiffness, standard straight-pull bladed stainless steel spokes and external nipples are used for easier servicing, and the hubs use a similar internal layout to Mavic's current design.

Of course, the Cosmic CXR 80 will work with other standard road tubulars as well and while Mavic would likely quote some degradation in aerodynamic performance as a result, we expect that it'd be rather modest.

Retail price for the Cosmic CXR 80 is set at €2,490 with US pricing still to be determined. Availability is currently scheduled for mid- to late August worldwide.

Testing, testing, testing

It's commonplace for aerodynamic wheel launches to be accompanied by pages of wind tunnel data (which invariably show the presenter's new model to be the best of the bunch). However, Mavic chose to launch the Cosmic CXR 80 at the wind tunnel in Geneva, Switzerland, where the actual testing was done, and we were able to watch some of the testing.

In fairness, we at Cyclingnews don't have sufficient technical knowledge to determine if the Geneva tunnel's protocols genuinely replicate real world benefits or if the programmed algorithms generate truly accurate drag data. However, it's difficult to find fault with the relative inflection points of the Cosmic CXR 80's and the Zipp 808 Firecrest's respective curves that were generated right before our eyes.

Mavic spent more than 400 hours in the wind tunnel last year

Mavic's claims at least seem believable and given the length of time that the company has delayed really getting heavily into the aero playing field, one would at least hope the company is doing it properly, particularly given the amount of time invested. According to Mavic, the spent more than 400 hours of wind tunnel time spread out over eight sessions in 2011 alone.

The facility also built a separate "stress balance" specifically dedicated to bicycle use – supposedly the only bike-specific test stage in the world – and claimed resolution is on the order of a single gram of drag. Mavic themselves even built a special widget that measures and records relative yaw angles and wheel rotation speeds in real-time – while riding.

For that kind of investment, the new Cosmic CXR 80 had better be good. We'll find out for sure when test samples arrive later this month.

More to come

Mavic introduced just this single wheel model at the launch and wouldn't confirm plans for future releases. However, the obvious dedication to aerodynamic testing recently – not to mention the glaring omissions in the current line-up – plus the known existence of other pro-only wheels currently undergoing testing such as the Classics-friendly M40 strongly hints that there is more to come. It's difficult to predict the timeline but we expect to see 40mm and 60mm CXR variants in the near future along with some sort of clincher version, too.

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