CeramicSpeed OSPW RS ALPHA — Shimano 105 Di2 (R7150)

An oversized pulley wheel system that finally gives 105 Di2 riders the same drivetrain efficiency the pro peloton runs. The CeramicSpeed OSPW RS ALPHA for Shimano 105 R7150 replaces the stock pulleys and cage with a hand-built, ceramic-bearing system that runs quieter, lasts longer, and frees up real watts on every climb and TT effort.

Why riders choose OSPW RS ALPHA for 105 Di2

Oversized 13T + 19T aluminium pulleys with ceramic bearings. The stock 11T pulleys on R7150 force the chain through tight bends that bleed watts and wear the chain quickly. Larger pulleys reduce chain articulation and friction so you save measurable wattage at threshold and your chain lasts visibly longer between replacements.

Up to 60% less drivetrain friction vs stock 105. Most riders never realise how much friction is hidden in the rear derailleur — it costs 2–3 watts at race power. The OSPW system gives those watts back so your 105 Di2 bike pulls level with bikes running far more expensive groupsets.

Carbon-fibre cage with sealed pivot. Stock plastic cages flex under hard sprints and big gear changes. The reinforced ALPHA cage stays rigid through full-power efforts so shifting stays crisp through every interval and group ride attack.

Custom seal, 60% better moisture protection. Wet rides and bike washes kill standard derailleur pulleys within a season. The redesigned seal blocks water and grit so the bearings keep spinning quiet through winter base miles and post-ride hose-downs.

Plug-and-play install in under 15 minutes. No chain length change, no derailleur recalibration — it bolts straight onto your existing R7150 derailleur with the supplied tools.

2-year warranty, 60,000 km service interval.

What's in the box

• OSPW RS ALPHA cage with 13T + 19T ceramic-bearing pulleys
• UFO TECH All Round Bearing Grease (5 ml)
• Mounting hardware + install tools
• CeramicSpeed decal

Fitment

• Derailleur: Shimano 105 RD-R7150 (Di2 12-speed)
• Drivetrain: 12-speed road
• Discipline: Road, Tri
• System weight: 96 g

Confirm your derailleur model code (printed on the inside cage) before ordering. If you're unsure, contact us and we'll confirm fitment for your bike.