JCB set the previous FIA world diesel land speed record at 350.092 mph with its Dieselmax car.
JCB
How JCB engineered the Hydromax to excel under extreme load
The initial technical partner meeting for the project with JCB, Prodrive, Ricardo, and Xtrac was held on June 5th, 2025, and almost a year to the day, the 32-foot JCB Hydromax rolled onto the tarmac at RAF Wittering for its very first run under its own hydrogen power. This marked the start of a full U.K. test program covering shakedown runs, hydrogen refuelling drills, and pit-stop rehearsals.
The JCB Hydromax is powered by two of the company’s own production-based hydrogen internal combustion engines, producing a combined 1,600 bhp — the same engines now powering JCB earthmoving machines.
It has been built to a rigorously engineered design. Around one kilometre of wiring runs through the car, and extensive use of 3D-printed components was used to keep weight down and packaging tight. The crankshaft is the same one JCB uses in its 448 hydrogen and diesel engines — highlighting how the land speed car is built on production hardware.
Keeping that hardware working at full power is a key engineering challenge. The pistons alone require one litre of cooling oil every second — as much oil flow as the rest of the engine combined — to stop them from overheating. A specially developed exhaust valve technology handles the temperatures generated by 1,600 bhp of hydrogen combustion. Each titanium turbo compressor spins at more than 150,000 rpm at roughly 300 degrees Celsius, pumping the equivalent of a standard bathtub of air every half-second.
On a full run, JCB Hydromax will consume just over two kilograms of hydrogen and produce 18 litres of water.
The U.K. testing puts every system under load for the first time: the powertrain, four-wheel-drive transmission, clutch, brakes, cooling, and bespoke control electronics. Hydrogen refuelling drills bring the pit crew, the on-car systems, and the fuel supply together at full pace, while pit-stop and tire change rehearsals will sharpen the turnaround times that, at Bonneville, can decide whether a record run goes ahead or not.
JCB to attempt the record this August
In early August the team will attend SpeedWeek, Bonneville’s land speed racing event, run by the Southern California Timing Association (SCTA). The team will then remain at the Salt Flats to pursue officially recognized world records under the FIA.
JCB has a long history of pushing land speed limits. In 2019, the JCB Fastrac tractor was crowned the world’s fastest tractor at 135.191 mph, and in 2014, the JCB GT set the world record for the fastest backhoe loader at 72.58 mph.
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