Threaded. Serviceable. Quiet. Now with ceramic bearings.

A T47 bottom bracket for frames with an 86mm threaded shell, built around SRAM's DUB 29mm spindle standard. Internal ceramic bearings, aluminum alloy construction, with the full spacer kit for both Road and Road Wide chainlines in the box.

What ceramic bearings actually do

Ceramic balls are harder, rounder, and lighter than steel balls, and those three properties do different things.

Rounder means less friction. Steel balls are ground to a tolerance; ceramic balls can be manufactured to a tighter sphericity and a smoother surface finish. Less deviation from a perfect sphere means less energy lost as the ball rolls through the race.

Harder means less deformation. Under pedaling load, a steel ball flattens slightly at its contact point. Ceramic resists that deformation, so the contact patch stays smaller and the bearing keeps spinning freely under the loads that matter — out of the saddle, in a sprint, grinding up a climb.

Lighter means less inertia, though on a bottom bracket that's a rounding error compared to the other two.

Being honest about the magnitude: the measurable power savings from ceramic bearings is small — single-digit watts at most, and often less than that. Anyone selling you more than that is selling. What you will notice, immediately and every ride, is how the cranks feel when you spin them: smoother, freer, and quieter than a steel bearing.

The stronger argument is longevity. A harder ball wears its race more slowly, and a smoother surface gives contamination less to grab onto. Keep the seals intact and a ceramic bearing outlasts a steel one.

Why T47 threaded beats press-fit

Press-fit bottom brackets are pressed into the frame with an interference fit. When that fit is even slightly off — from manufacturing tolerance, from a frame that's flexed, from a cup that's worked loose over a season — you get creaking. And press-fit creak is famously hard to chase, because the noise travels and the fix usually means pulling the whole thing back out with a press.

T47 threads in. A threaded interface doesn't rely on tolerance to stay put; it relies on threads, which either engage or don't. Quieter, better aligned, and longer-lived because the bearings aren't being subtly distorted by an imperfect press.

It's also the standard you can service yourself. Threaded cups install and remove with a standard bottom bracket tool. No press, no drift, no shop visit.

That matters more on a ceramic bottom bracket than a steel one: you're spending more, so being able to keep it clean and properly preloaded yourself is what protects the investment.

Fitment — three things have to match

If you're unsure about your shell standard, measure the width of your bottom bracket shell and look for threads inside it. A T47 shell is visibly larger than a BSA shell and has threads all the way through.

Road and Road Wide, both covered

SRAM's road cranks come in two chainlines, and which one you have determines how the bottom bracket gets spaced.

• Standard Road — 45mm chainline. The setup on most road bikes and shorter-chainstay all-road frames. Uses the 1mm, 2mm, and/or 3mm spacers.
• Road Wide — 47.5mm chainline. The wider setup for gravel frames with longer chainstays and bigger tire clearance. Uses the 2.5mm and 5.5mm spacers.

All five spacers ship in the box, so you can run either configuration and change your mind later if you swap cranksets.

Internal bearing design

The bearings sit inboard, inside the shell, rather than hanging outboard of it. On an 86mm shell that's the right arrangement — a wider bearing stance supports the spindle better without adding width at the cranks, so Q-factor stays where the frame designer intended.

Sealed cartridge construction keeps water and grit out, which is what determines how long any bearing lasts, ceramic or not.

Specifications

• Standard: T47 threaded
• Shell inner diameter: 47mm
• Shell width: 86mm
• Spindle compatibility: SRAM DUB, 29mm
• Bearing type: Internal ceramic, sealed cartridge
• Material: Aluminum alloy with composite internals
• Chainline: Road (45mm) and Road Wide (47.5mm)
• Spacers included: 1mm, 2mm, 3mm (Road) · 2.5mm, 5.5mm (Road Wide)
• Color: Black

Installation

You'll need a bottom bracket tool that matches the cup interface and a torque wrench. Grease the frame threads before installation — the single most effective thing you can do to prevent creaking and to make removal possible in two years.

Note the thread direction. Like most threaded bottom brackets, the drive side is reverse-threaded. Turning it the wrong way with force is how threads get damaged.

Set your spacers before final torque, following SRAM's spacing chart for your crankset and chainline. Then set the crank's preload collar properly — not so tight that there's drag, not so loose that there's play.

Preload matters more here than on a steel bearing. Over-tightening a ceramic bearing loads the balls against the races harder than they're designed for, which trades away the low friction you paid for and shortens the bearing's life.

Care

Keep the seals intact and don't aim a pressure washer at the bottom bracket shell. Ceramic balls are harder than the races they run in, so if grit does get past the seals it can score the races faster than a steel ball would.

Kept clean, this is a bearing that outlasts steel. Neglected, it doesn't — the seals are what you're really protecting.