CeramicSpeed BB90 Bottom Bracket Bearing 25x37x6mm - Compatible with Shimano & GXP Drive Side (61805) - High-Performance Bicycle Upgrade for Road & Mountain Bikes

This CeramicSpeed BB90 bearing is specifically designed for the drive-side position on Trek BB90 frames using Shimano road cranks or SRAM GXP cranks with a 25mm spindle. It features a 25x37x6mm bearing size and requires the Trek "Top Hat" reducer sleeve for proper fitment and spacing when installed.

The Trek Shimano Top Hat is a small aluminum or plastic adapter that sits inside the bearing bore and steps the ID down from 25mm to 24mm to match the spindle of a standard Shimano crankset. For SRAM GXP cranks, it supports the drive-side interface by acting as a bearing surface and fit adapter. Without the Top Hat, the bearing ID would be too large to support the crank spindle directly.

Why CeramicSpeed?
Hand-built in Denmark, all CeramicSpeed bearings feature Grade 3 Silicon Nitride balls, matched within microns to hardened steel races polished to an ultra-smooth groove. The reinforced polyamide cage and non-contact seals ensure minimal rolling resistance and maximum protection from dirt and moisture.

Each bearing is factory-lubricated with CeramicSpeed’s low-viscosity Blue Grease, engineered to reduce friction and extend longevity. During production, every bearing is inspected by hand four times to ensure flawless quality and performance.

CeramicSpeed balls are up to 400% smoother, 128% harder, and 58% lighter than typical steel balls. Compared to other ceramic bearings, CeramicSpeed balls are 15% harder, support 99% higher loads, and are 100% smoother.

Specifications:

• Brand: CeramicSpeed

• Part Number: 61805RS

• Standard: Trek BB90

• Bearing Size: 25x37x6mm

• Position: Drive-side bearing for Shimano or GXP cranks

• Shimano Compatibility: Requires Trek Top Hat reducer sleeve

• Material: CeramicSpeed-grade silicon nitride balls, hardened steel raceways

• Grease: Low-friction CeramicSpeed Blue Grease

• Seals: Non-contact

• Weight: Net 15.55g / Gross 16g

• Category: Single bearing

Includes only what is pictured. This is a single bearing sold individually.

These are genuine CeramicSpeed bearings sourced directly from the manufacturer to guarantee authenticity.

This CeramicSpeed BB90 bearing is specifically designed for the drive-side position on Trek BB90 frames using Shimano road cranks or SRAM GXP cranks with a 25mm spindle. It features a 25x37x6mm bearing size and requires the Trek "Top Hat" reducer sleeve for proper fitment and spacing when installed.

The Trek Shimano Top Hat is a small aluminum or plastic adapter that sits inside the bearing bore and steps the ID down from 25mm to 24mm to match the spindle of a standard Shimano crankset. For SRAM GXP cranks, it supports the drive-side interface by acting as a bearing surface and fit adapter. Without the Top Hat, the bearing ID would be too large to support the crank spindle directly.

Why CeramicSpeed?
Hand-built in Denmark, all CeramicSpeed bearings feature Grade 3 Silicon Nitride balls, matched within microns to hardened steel races polished to an ultra-smooth groove. The reinforced polyamide cage and non-contact seals ensure minimal rolling resistance and maximum protection from dirt and moisture.

Each bearing is factory-lubricated with CeramicSpeed’s low-viscosity Blue Grease, engineered to reduce friction and extend longevity. During production, every bearing is inspected by hand four times to ensure flawless quality and performance.

CeramicSpeed balls are up to 400% smoother, 128% harder, and 58% lighter than typical steel balls. Compared to other ceramic bearings, CeramicSpeed balls are 15% harder, support 99% higher loads, and are 100% smoother.

Specifications:

• Brand: CeramicSpeed

• Part Number: 61805RS

• Standard: Trek BB90

• Bearing Size: 25x37x6mm

• Position: Drive-side bearing for Shimano or GXP cranks

• Shimano Compatibility: Requires Trek Top Hat reducer sleeve

• Material: CeramicSpeed-grade silicon nitride balls, hardened steel raceways

• Grease: Low-friction CeramicSpeed Blue Grease

• Seals: Non-contact

• Weight: Net 15.55g / Gross 16g

• Category: Single bearing

Includes only what is pictured. This is a single bearing sold individually.

These are genuine CeramicSpeed bearings sourced directly from the manufacturer to guarantee authenticity.