HED Jet 180 180mm-deep rim . has a radical rear wheel with

HED has announced the Jet 180, a new rear wheel with a 180mm-deep rim.

The Jet 180 is specifically designed for athletes competing at the Ironman World Championships in Kona, Hawaii. Full rear disc wheels have been banned in the Kona due to safety concerns in windy conditions.

The 180mm-deep rim has a maximum outer width of 32.5mm and an inner width of 21mm.

It is tubeless-compatible and available in both rim and disc brake Form. Claimed weight is 1,229g for the wheel as a disc brake, or 1,258g as a rim brake.

HED hasn’t announced pricing yet, but has indicated availability is currently four to six weeks out of order, with a limited number of wheels available at the 2022 Ironman World Championships in Kona.

How fast is the HED Jet 180?

The rear wheel of the HED Jet 180 uses the darkest rim we’ve seen.

At the time of writing, HED has not published any performance claims or data compared to other, more traditional aero wheels in its range, such as jet 6 either jet disc,

That said, the purpose of the wheel appears to be to mimic the rim surface area of ​​a disc wheel as closely as possible, within the limits imposed by race organizers at Kona.

The significantly increased rim surface area of ​​disc wheels and rims thus helps improve aerodynamic efficiency in two ways, depending on how the wind is hitting them.

The vast surface area of ​​the rim is designed to optimize aerodynamic efficiency.

In a head wind or cross headwind, the deep rim or surface of a solid disc helps to keep the airflow attached to the wheel for as long as possible. This reduces turbulent air flow and reduces drag.

In a tailwind or cross-tailwind, the surface area of ​​the rim acts as a sail, helping to propel the rider forward with greater efficiency.

Can this rim be used on a front wheel?

As things stand, the HED Jet 180 is only available as a rear wheel.

Theoretically, yes, although HED is only offering it as a rear wheel for now.

Neither the ITU (International Triathlon Union) nor the UCI (Union Cycliste Internationale, cycling’s world governing body), place a specific restriction on front-wheel rim depth in individual time trials.

Britain’s time trial governing body, the CTT however places a limit on front rim depth. Its rules state that a front wheel “must have at least 45 percent of the surface area open”, although how this would be measured in an event is unclear.

Solid rear disc wheels are commonplace in the time trial world, but could we soon see even darker rims on the front?
Simon Von Bromley / Instant Media

Regulations aside, however, the primary issue holding people back will likely be concerns about tackling.

A super-deep rim may be theoretically faster than a shallow one (all else being equal), but if that prevents you from confidently having optimal aero position on the bike as it keeps catching air, you’ll slow down Altogether.

However, today’s wider and more refined rim profiles generally offer significantly better handling characteristics than rims of the past.

As a result, time trial and triathlon experts are regularly pushing the envelope for incremental gains.

Super-deep front rims, such as this unbranded Aerocoach AEOX Titan, are increasingly common in WorldTour time trials.
Simon Von Bromley / Our Media

Aerocoach’s AEOX Titan front wheel, which has a 100mm-deep rim, has seen widespread use in recent years by some of the world’s top testing experts, such as Filippo Gaana, Geraint Thomas and Vout van Aert.

Rumors have even spread that at least one world tour team Have tested the front disc wheel for time trial use on the road, and haven’t ruled out the possibility of using it in race scenarios.

So, if HED makes this rim available for use as a front wheel, you can be sure that this marginal advantage will generate some interest among chasers.

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