Custom Triumph Castleton T120: Rugged, Moody, and Unapologetically Tough

PUBLISHED 13.02.2026

Following on from the Dakota and Libertad y Felicidad builds, the Castleton T120 marks the latest collaboration between Stockwell Design and Triumph London, and it continues an unmistakable direction. Rugged. Moody. Unapologetically tough.

Built on the iconic Triumph Bonneville T120 platform, the Castleton leans away from café racer polish and toward something more grounded. Classic British heritage remains at its core, but here it’s filtered through a darker, more muscular lens. Less refinement for show. More presence for the street.

The design language is deliberate. Blacked-out components create a stealth aesthetic that tightens the silhouette and lowers the visual weight of the bike. A chunkier stance, reinforced by Heidenau K60 Scout tyres front and rear, gives the T120 a planted, urban confidence.

The custom paintwork, finished in Gravel Grey and Denim Black, keeps graphics to a minimum. No excess striping. No unnecessary flash. Just depth, tone, and texture, with premium finishes that elevate the platform without softening its edge.

Shortened Motone fenders front and rear clean up the profile, while a Motone El Dorado LED rear light and discreet Motogadget mini indicators keep the lighting modern and minimal. A BAAK headlamp bracket paired with a Tamarit headlamp cage sharpens the front end, bringing a subtle scrambler influence to the Bonneville’s classic proportions.

At its core, the 1200cc parallel twin remains untouched: torquey, responsive, and unmistakably Bonneville. The modifications here are about attitude rather than compromise.

Hitchcox black slip-ons deepen the soundtrack, while Fox Racing rear suspension adds composure and control. A gold D.I.D chain paired with a black billet rear sprocket introduces contrast at the rear wheel for a small but deliberate detail that reinforces the build’s mechanical honesty.

Blacked-out throttle bodies further darken the engine’s profile, tightening the overall visual language and keeping the focus on stance and silhouette.
 

What defines the Stockwell approach is not excess, but intention. Respect for the original lines. Premium materials. Subtle but deliberate customisation. A balance of aggression and refinement.

Where the Dakota hinted at refined rebellion and Libertad y Felicidad carried cultural narrative, the Castleton strips things back to something more elemental. It feels built for cold morning city rides and late-night urban runs. Less about spectacle. More about presence.

The Castleton T120 isn’t designed to shout. It’s built to stand its ground.