French manufacturer Duke has introduced two brand-new carbon wheelsets built around the 32-inch format: the Lucky Jack SLS5 32in aimed at cross-country racing, and the Sierra 42 32in designed for gravel riding.
According to Duke, the XC-oriented model is “already a winner,” since a prototype version secured a stage victory at the Cape Epic earlier this year beneath rider Felix Stehli.
The company emphasizes that both wheelsets were engineered specifically for the larger diameter rather than being stretched versions of its current 29in and 700c offerings. Duke explains that a larger wheel reacts differently whether on dirt or pavement — it generates greater leverage on the rim, carries more inertia, and produces altered spoke angles. These factors demanded a clean-sheet design approach.
Pricing for complete Lucky Jack SLS5 32in wheelsets begins at €1,559 when fitted with a DT Swiss 370 CL SP hub, and climbs to €2,489 with Chris King hubs. The rim alone is priced at €607.
For the Sierra 42 32in, complete wheelsets start at €1,659 paired with a Baron CL SP hub, reaching €2,599 when equipped with Chris King R45 CL hubs. The rim by itself costs €649.
Lucky Jack SLS5 32in
The Lucky Jack SLS5 serves as Duke’s cross-country offering. In addition to Stehli’s Cape Epic stage win, the Singer KTM Racing squad is scheduled to compete on it at the UCI Mountain Bike Marathon World Cup.
While this wheel has existed in other sizes for some time, Duke insists the 32in variant was developed entirely from scratch. The rim is produced through the company’s SLS5 manufacturing technique, which Duke claims delivers a 10% weight reduction versus the prior generation, along with enhanced vertical compliance, superior impact resistance, and better vibration absorption.
The rim features a hookless design, molded spoke holes, and a finish that skips varnish entirely.
Duke offers three rim configurations. Two of them share a 31mm internal width, 4mm offset, and 28-hole spoke pattern, tipping the scales at 360g and 400g respectively. The third carries a 29mm internal width and weighs 410g, and it incorporates the brand’s AntiPinch rim edge, which is designed to reduce puncture risk. Duke suggests combining a lighter front rim with the 410g rear option.
In its lightest configuration — using Duke’s own hubs and Sapim spokes — the complete wheelset is quoted at 1,233g, with a stated tolerance of plus or minus 30g. Duke advises tire widths between 2.2 and 2.4in, aligning with contemporary XC standards.
Sierra 42 32in
The Sierra 42 represents Duke’s gravel wheel, presented as an evolution of the current Sierra 42 that gains the rollover benefits of a larger diameter. It is constructed from Toray T1100 carbon fiber via Duke’s SLR5 process, which the brand says reduces weight by as much as 23% compared to the earlier iteration.
In contrast to the XC rim, this one uses a hooked profile suited to road and gravel tire pressures. It measures 42mm deep, carries a claimed weight of 390g, and has a 28mm internal width.
Duke lists a starting weight of 1,270g for complete pairs and recommends tire widths spanning 40mm to 2.2in.
Additional gravel rim choices are reportedly in the pipeline, though Duke has not disclosed a release schedule.
