Royal Enfield has taken a bold step towards infusing racing pedigree into its lineup by collaborating with renowned Spanish custom motorcycle builder XTR Pepo. The result of this partnership is the stunning Royal Enfield GRR, a one-off supermono sportsbike based on the recently launched Guerrilla 450.
The GRR made its official debut in June at the Wheels and Waves Festival in Biarritz, France—a five-day event celebrating motorcycles, surf culture, and cutting-edge custom builds. Each year, the festival showcases factory-supported projects, and this year’s GRR certainly captured attention.
The bike is built upon the Royal Enfield Guerrilla 450, launched in 2024, which features a 452cc liquid-cooled, Euro5-compliant single-cylinder engine, delivering a claimed 39bhp. But this machine is far more than a simple styling exercise.
The brainchild of single-cylinder enthusiast Pepo Rosell, the GRR was designed with one clear goal: to be as light and fast as possible. Through extensive weight reduction measures, Rosell managed to shed an impressive 53kg, reducing the standard Guerrilla 450’s kerb weight from 184kg to just 131kg, dramatically improving performance and handling.
To achieve this transformation, Rosell collaborated with Italian specialist Futura 2000, employing 3D modeling, prototyping, and custom fibreglass moulds for the bike’s sleek fairings. The fuel tank, seat, and tail section are a lightweight monocoque design, complete with a transparent fuel strip for quick visual level checks.
Performance enhancements continue with a modified aluminium swingarm, adapted from the Aprilia RS660, paired with a bespoke Nitron R1 rear shock. The stock front end has been replaced by 43mm adjustable Showa inverted forks, offering superior control with both rebound and compression adjustability.
Styling cues nod to the racing heritage of the 1980s, particularly with the tinted aftermarket front light inspired by the iconic Honda RC30. The GRR rolls on lightweight Dymag CH3 wheels, featuring classic three-spoke styling reminiscent of the bikes ridden by racing legends like Eddie Lawson. These aluminium wheels are wrapped in grippy Continental ContiSportAttack 2 tyres, ensuring optimal traction for the bike’s lightweight, punchy setup.
Further modifications include a redesigned frame with a bespoke subframe to accommodate the new single seat and higher tail section. Adjustable footpegs provide increased ground clearance for aggressive cornering, while clip-on handlebars enhance the bike’s sporty, track-focused ergonomics.
Acoustic and performance upgrades include a larger airbox and a distinctive 45mm exhaust system, routed along the side of the engine and capped with a Spark titanium silencer, delivering both visual impact and a more aggressive exhaust note.
Completing the performance package are Discacciati CNC-machined twin front brake calipers paired with larger, lightweight discs for improved stopping power.
While the GRR is a one-off, factory-supported project, its development hints at Royal Enfield’s growing interest in exploring the sporting potential of their 452cc engine platform, signaling exciting possibilities for the future of lightweight performance motorcycles.
