Forged carbon outside. Bikone ceramic bearings inside.

Look at a carbon pulley and you see the shell. What decides how it rides is the bearing in the middle, and a pulley bearing has a rough job: thousands of revolutions a minute at bunch pace, sitting low on the bike in whatever spray and grit the last wet Sunday threw at it.

So that is where these start. Forged carbon bodies handcrafted in Gemini's Barcelona workshop, built around ceramic bearings Bikone developed specifically for pulley duty. ABEC 7 grade, a different bearing in the top wheel than the bottom because the two do different work, sealed behind labyrinth dust covers, and re-greasable with the grease in the box. Fit them with the titanium bolts supplied and the back of your bike runs smoother and quieter, and keeps running that way.

In the box

• 2 × forged carbon pulley wheels (upper guide and lower tension)
• 1 × Bikone Speed Grease for ceramic bearings, 3 ml
• 2 × titanium bolts

Why it works

• Bikone ABEC 7 ceramic bearings. Stainless-steel races and ceramic balls, developed by Bikone for pulley duty rather than borrowed from another application. Low friction and smooth at the high rotational speeds pulleys actually see, built for long-term performance.
• A bearing per position. The upper guide pulley runs a dedicated shifting bearing that minimises unwanted play, so the derailleur holds its position and the gear changes stay accurate. The lower tension pulley runs a more forgiving configuration that copes with chain angle when you're cross-chained, and sheds friction doing it.
• Sealed against the road. Both bearings sit behind a labyrinth seal system that keeps water, dust and grit out, backed by low-friction silicone seals that seal without dragging.
• Re-greasable. The bearings run Bikone's high-speed, low-friction grease, with detergent additives that lift degraded grease out of the bearing. Grease-level protection, oil-like friction, and a 3 ml bottle in the box so you can service them yourself.
• Larger diameter. The biggest that fits a standard rear derailleur cage. Less chain articulation around the pulley means less drivetrain friction, with no cage modification and nothing given up on shifting.
• Narrow-wide teeth. Alternating narrow and wide teeth on an asymmetric profile keep the chain seated and guided. Controlled chain movement, precise shifts, less noise.
• Aero profile. A solid body shaped at both the chain-contact area and the bearing interface to work with the air moving around the drivetrain, not against it.

Specs

• Weight: 22.2 g the pair (25.1 g for SRAM E1)
• Body: forged carbon, handcrafted by Gemini in Barcelona
• Bearings: Bikone ABEC 7 ceramic, stainless-steel races with ceramic balls
• Seals: labyrinth dust covers with low-friction silicone seals
• Bolts: titanium, included
• Grease: 3 ml Bikone Speed Grease for ceramic bearings, included

Compatibility

• Shimano Ultegra / 105 Di2, 11-speed and 12-speed (12T upper, 14T lower)
• Shimano Dura-Ace Di2, 11-speed and 12-speed (12T upper, 14T lower)
• SRAM Red / Force / Rival D1, 12-speed (12T upper, 14T lower)
• SRAM Red / Force / Rival E1, 12-speed (12T upper, 16T lower)
• Uses the largest pulley size your rear derailleur's standard cage takes. No cage swap or modification needed.

Service and support

Carbon from Barcelona, bearings from Spanish specialists Bikone, and we look after both here. Warranty, spares and bearing questions go through us in Australia, not an overseas returns portal. If you want to keep the whole drivetrain honest, the threaded DCTech bottom brackets run the same bearing programme, and the rest of the range is on the Bikone collection page.