CeramicSpeed BB ALPHA for T47a SRAM DUB Road

 

Danish-made flagship ceramic bottom bracket for T47a asymmetric threaded frames (47mm bore, 77mm asymmetric shell width) paired with SRAM DUB 28.99mm axle road cranksets. Grade-3 Silicon Nitride ceramic balls, hardened stainless-steel races, 500% moisture protection improvement, 101g, hand-built in Denmark with lifetime warranty. Black finish.

BB ALPHA is CeramicSpeed's flagship bottom bracket line, engineered to outlast your frame. This model fits T47a asymmetric threaded frames paired with SRAM DUB 28.99mm axle cranksets, and is designed for road, triathlon, and track disciplines.

T47 is a relatively new threaded bottom bracket standard, co-developed by Chris King and Argonaut Cycles. Its design philosophy was to combine the installation advantages of traditional threaded BBs — such as BSA/English thread — with the structural benefits of a modern large-diameter shell. Traditional threaded BBs offer creak-free operation (the cups are torqued into threads, eliminating the movement that plagues press-fit designs), straightforward maintenance, and no requirement for expensive pressing tools. T47 uses a 47mm bore diameter (significantly larger than BSA's 34.8mm), accommodating larger bearings and providing ample space and superior stiffness support for modern oversized crankset spindles. The threaded cups screw into the internal threads of the frame's BB shell and are secured to a defined torque, completely avoiding the cup loosening and frustrating creaking that can occur with press-fit designs. Servicing and replacement are also far simpler than press-fit.

The "a" in T47a stands for "asymmetric" — the BB shell is 77mm wide with an asymmetric design where the drive side (right) is longer than the non-drive side (left). This shifts the drive-side bearing outboard, providing better chainline alignment while giving carbon frame designers more freedom to optimise chainstay and rear wheel clearance. This asymmetric layout is increasingly adopted by premium road frame manufacturers including Specialized (Tarmac SL7/SL8, Aethos, etc.), Trek (select models), Cervélo, Factor, Allied, Argonaut, and others.

SRAM DUB (Durable Unified Bottom bracket) cranksets use a unique 28.99mm spindle diameter — positioned between the traditional Shimano 24mm and the 30mm standard — designed to provide a single spindle size compatible with all major BB standards. DUB cranks are widely used across SRAM's road groupsets including Red AXS, Force AXS, and Rival AXS. Because of this non-standard 28.99mm dimension, T47a frames require a purpose-built bottom bracket specifically adapted for DUB to ensure the bearing inner diameter, preload setting, and axial alignment are precisely correct. The CeramicSpeed BB ALPHA for T47a SRAM DUB Road is engineered for exactly this requirement.

The bearing core uses grade-3 Silicon Nitride (Si₃N₄) ceramic balls paired with hardened stainless-steel races. The ceramic balls offer an exceptionally smooth surface and far greater hardness than steel, resulting in ultra-low friction and outstanding longevity. The hardened stainless-steel races are inherently corrosion resistant — ideal for riding in Hong Kong's hot and humid conditions where sweat and rain are constant challenges. The product features a black finish for a clean, understated aesthetic.

Protection is where BB ALPHA truly excels. Custom-engineered seals and precision dust covers were refined through 28 design iterations for optimal fitment, delivering 500% better moisture and contamination resistance than conventional designs. While threaded designs inherently offer somewhat better sealing than press-fit (the threaded cup-to-frame interface is more enclosed), BB ALPHA's 500% protection improvement remains critical — particularly for riders who frequently ride in wet conditions, regularly wash their bikes, or compete in triathlon events involving water stages. Top-tier sealing performance means the bearings maintain their initial smoothness for thousands or even tens of thousands of kilometres.

Structurally, the cups feature optimised material and geometry for maximum strength at reduced weight, while a simplified spacer tube design uses fewer parts for quicker, more intuitive installation. Together, these changes achieve a 10% weight saving over the previous generation, bringing the net weight to just 101g. The threaded installation also ensures that future maintenance and bearing replacement require no special pressing tools — simply unscrew the cups. The included DUB Spacer Kit ensures that the SRAM DUB crankset achieves the correct axial positioning within the T47a shell.

Every BB ALPHA is hand-assembled and quality-checked at CeramicSpeed's factory in Holstebro, Denmark, and is backed by a lifetime warranty for ultimate peace of mind.

Key Features

• Ultra-Low Friction: Grade-3 Si₃N₄ ceramic balls with hardened stainless-steel races for dramatically lower drag than steel bearings
• 500% Moisture Protection: Custom seals and dust covers refined through 28 iterations to block water and contamination
• Corrosion Resistant: Hardened stainless-steel races resist rust — perfect for humid climates and sweat exposure
• Lightweight Design: 101g net weight — 10% lighter than the previous generation through optimised cups and spacer tube
• Threaded Installation: T47a standard 47mm × 77mm asymmetric threaded, creak-free operation and easy maintenance
• SRAM DUB-Specific Fit: Purpose-built for SRAM DUB 28.99mm axle cranksets with included DUB Spacer Kit for precise alignment and optimal preload
• Serviceable: Seals and dust covers are independently replaceable; threaded cups are easy to remove and reinstall without pressing tools
• Lifetime Warranty: Official CeramicSpeed lifetime warranty
• Black Finish: Clean, understated aesthetic that complements any frame colour

In the Box

• BB ALPHA for T47a SRAM DUB Road × 1
• DUB Spacer Kit × 1
• UFO TECH All Round Bearing Grease 5ml × 1
• CeramicSpeed Decal × 1

Frame Compatibility

All road frames using the T47a asymmetric threaded bottom bracket standard (47mm bore diameter, 77mm asymmetric shell width, internal threads). This standard is commonly found across brands such as Specialized (Tarmac SL7/SL8, Aethos, Venge), Trek (select models), Cervélo (select models), Factor, Allied, Argonaut, Open, Parlee, and others.

⚠️ Before installation, confirm your frame's BB shell is T47a (47mm × 77mm asymmetric, internally threaded). Do not confuse with T47 symmetric (68mm or 68.5mm shell width) — while both share the 47mm threaded bore, shell widths differ and the corresponding bottom brackets have different lengths. If your frame spec sheet states "T47a", "T47 Asymmetric", or "T47 77mm", it is compatible with this product. Note that some earlier frames use the symmetric T47 version, which requires a different model.

Crank Compatibility

All SRAM DUB 28.99mm spindle road cranksets, including but not limited to: SRAM Red AXS, Force AXS, Rival AXS, Red eTap AXS (12-speed), and earlier-generation SRAM road cranksets that support the DUB standard.

⚠️ If your T47a frame requires a Shimano 24mm spindle crankset, please select the corresponding T47a Shimano version. This product is designed exclusively for SRAM DUB 28.99mm spindle cranksets.

Installation Notes

T47a uses a threaded design, meaning the cups screw into the frame's internal threads using an appropriate torque wrench and T47 cup tool. This BB shares installation procedures with BSA and ITA threaded bottom brackets. Before installation, thoroughly clean the frame's BB shell internal threads and apply an appropriate amount of grease (UFO TECH grease is included) to ensure smooth thread engagement and prevent thread seizing. The CeramicSpeed Dual Socket Tool T45 Colnago/T47 is recommended for installing and removing the cups. When installing SRAM DUB cranksets, use the included DUB Spacer Kit to set the correct axial position, and the CeramicSpeed Preload Ring for SRAM DUB is recommended for optimal preload adjustment.

💡 The key advantage of threaded installation: as long as threads are in good condition and tightened to the correct torque, threaded BBs will never exhibit the creaking common in press-fit designs, and future removal for service is straightforward.

Recommended Accessories

• CeramicSpeed Dual Socket Tool T45 Colnago/T47 (T47 cup installation tool) 
• CeramicSpeed Preload Ring for SRAM DUB 
• CeramicSpeed Crank Bolt Removal Tool