T47 Internal Bottom Bracket

Rotation Engineering’s internal T47 bottom brackets are made right here in Connecticut out of U.S.-sourced 7075-T6 aluminum. Small but necessary refinements set our products apart from our competition.

• The STANDARD bearing option features hardened 52100 high chromium races coated in our PEEK cage, hardened steel ball bearings, two low-friction rubber seals, and a specially formulated anti-corrosion low-friction bearing grease. This option is for the more budget-oriented customer that still wants a premium, USA-made bottom bracket.
• The ULTIMATE bearing option features one low-friction rubber seal facing out, one non-contact PEEK shield on the inside, a PEEK bearing cage, a specially formulated ceramic-bearing-optimized low-friction grease, silicon nitride (ceramic) balls, hardened 52100 high chromium bearing races that have been polished and coated with WS2 & TDC for the ultimate blend of durability and performance. This option is for the consumer who wants the ULTIMATE, period!

KEY DESIGN ELEMENTS:

1. Optimized bearing bore tolerance to minimize bearing compression for lower friction.
2. Installation tool splines have been uniquely machined to keep the BB installation socket from scoring your frameset during installation
3. We offer two pre-assembled bearing options STANDARD and ULTIMATE (description above).
4. Our bearing ID reducers are machined from high-density Delrin, not injection-molded plastic, to guarantee perfect fitment and protect the crank spindle from wear and fretting
5. Frame and crank fitment, we support three crank spindle diameters (29mm-24mm/30mm) and two frame width options (86mm-85.5mm).
6. We control all aspects of our BB production through design, testing, manufacturing, quality control checks, and assembly, it gives us the ability to refine our product and ensure consistency much better than our mass-produced competition. We also never rest on our laurels! We continuously test other specialty bearing options so please feel free to inquire or check out our recommended options in our “spare parts “ section.