Core SL Carbon Wheelset

The Core SL is our most advanced road wheelset to date. Lightweight, responsive, and built to last.

The SL combines a new carbon layup, ceramic bearings, and ultra-light unidirectional carbon spokes into a package that’s both lightweight and remarkably resilient.

At just 1275 grams, the Core SL shaves meaningful rotational mass, delivering sharper acceleration and greater responsiveness under load. Its 50mm rim depth strikes a balance between aerodynamic efficiency and predictable handling, while the 23mm internal width pairs seamlessly with wider tyre profiles to enhance aerodynamics and grip. The hooked rim design ensures broad tyre compatibility and easy tubeless setup.

What sets the Core SL apart is its spoke system. We’ve developed new UD carbon spokes specifically for this wheelset, engineered to improve lateral stiffness while significantly reducing weight. Compared to a traditional steel build, the result is over 200 grams saved and a tighter, more reactive ride feel that rewards every effort.

At the centre is the new Bossi Core SL hubset, equipped with TPI ceramic bearings for reduced rolling resistance and lasting durability. The spoke layout—20 front, 24 rear is optimised for a balance of strength, stiffness, and weight. Like every Bossi wheelset, the Core SL is hand-built to exacting tolerances for consistency you can count on.

Visually, the UD marble finish is subtle but distinct. No two sets are identical. The natural variance in the layup reflects the bespoke nature of the product. Eye-catching. Purposeful. Design values that permeate all our products

The Core SL is designed for performance, but built for the long haul. It reflects everything we stand for: minimalist, functional, and quietly confident.

RIM

• 50mm T800-T1000 carbon rim, tubeless ready
• 23mm hooked internal rim width (25mm wall to wall)
• 30.5mm external rim width, aerodynamically optimised for 28-30c tyres.
• Reinforced nipple hole patching
• Counterbalance balast patch opposite valve
• Laser engraved logos
• Marbled carbon finish
• 120 PSI max tyre pressure
• ERD = 539mm

HUB

• TPI Ceramic bearings front and rear
• Star ratchet, 45T, 8 degree engagement
• Rear lacing pattern - 24 spoke, 2:1, Cross 2 DS and NDS
• Front lacing pattern - 20 spoke, 1:1, Cross 2 DS and NDS
• 7075-T6 Forged alloy /heat treated hub body
• 7075-T6 CNC axles

WHEEL

• T1000 UD carbon bladed spokes, T head, threaded
• External nipple, black anodized
• 5 year warranty
• 120kg system limit
• 1275g +/- 15g

Experience enhanced control with our new 50mm rim. Designed for aerodynamic efficiency without compromising stability. Confident and predictable, even in crosswinds. Featuring an all new layup with T800/T1000 fiber, our new rim is lighter, and stiffer than its predecessor.

Boasting exceptionally high strength-to-weight and deep aero design. Our unidirectional carbon spokes weigh less than 3 grams each. The material offers significantly higher tensile strength compared to traditional steel spokes, contributing to improved lateral stiffness and responsiveness under load.

Our all-new Core-SL hubset is purpose-built for carbon spokes. It features premium TPI ceramic bearings and a 45-tooth ratchet system for reliable engagement and easy serviceability. Large flanges for optimal bracing angles and tangentially laced spokes for maximum torsional stiffness

Our new raw, unpainted aesthetic that celebrates the true nature of unidirectional carbon fiber. Each rim reveals a unique marbled texture, formed during the molding process and never exactly replicated. Just like our bikes, no two are ever the same. Showing off the craftsmanship, material integrity, and individuality that define every Bossi bike.

We've used laser engraving to apply a subtle, refined finish to our rim branding. The process is carefully controlled to etch only the surface weave, leaving the structural carbon layers untouched. The engraving ensures your graphics can't peel or scratch off over time.

The new forged 7075 hub body is light, stiff, and durable resulting in exceptional performance and stability. Bearing interfaces are precision machined to ensure perfect fit, improving performance and extending lifespan.

We use external nipples for easier maintenance and long-term serviceability. Alowing for for quick and precise truing without the need to remove tyres or rim tape, making it easier to keep your wheels running perfectly true. It’s a practical choice that prioritises performance and reliability.

2:1 tangentially laced spokes keep spoke tension even on both sides of the wheel and improve bracing compared to conventional radial lacing. The unique 2:1 tangentially laced spokes ensure consistent spoke tension and enhance stability.