PHIL WOOD Philcentric Outboard BB｜Convert Your Cherished Bike into a Single Speed

A special bottom bracket that transforms your favorite bike into a simple yet profound single-speed, without changing the wheels or altering its characteristic appearance.

For those who want to enjoy their long-ridden MTB, cyclocross, or road bike as a single speed without adding unnecessary parts, the PHIL WOOD Philcentric Outboard BB is an eccentric bottom bracket made just for them.

It installs into a standard BSC threaded BB shell, and by offsetting the BB spindle position, it allows for chain tension adjustment. This enables you to leverage your existing rear wheel and brake position while enjoying the direct pedaling feel unique to single speeds and a clean, minimalist silhouette.

The inner surface of the outer shell features fine splines, adopting a structure that resists displacement even during strong pedaling or dirt riding. It boasts a robust body primarily made of stainless steel and the smooth rotational performance characteristic of Phil Wood products.

Features

• Eccentric bottom bracket installable into standard BSC threaded BB shells
• Allows chain tension adjustment by offsetting the BB position
• Enables single-speed conversion without changing the existing rear wheel or brake position
• Internal spline structure suppresses displacement under high load
• Available for SHIMANO HOLLOWTECH II and SRAM GXP/TRUVATIV
• Compatible with a wide range of bikes including MTBs, cyclocross, and road bikes

SPEC

• Standards: SHIMANO HOLLOWTECH II, SRAM GXP/TRUVATIV
• Compatible BB shell width: 68mm, 73mm
• Thread standard: BSC / British
• Thread direction: Right cup reverse thread, left cup standard thread
• Main materials: Stainless steel, aluminum
• Purpose: Single-speed conversion for threaded BB frames
• Installation requires Phil Wood specialized tools and symmetry adjustment
• BB height and crank fore-aft position will slightly change depending on the eccentric position
• Not installable on full-suspension MTBs except those with a coaxial BB pivot

The ability to convert to a single speed without a tensioner and by utilizing your current rear wheel is a major draw. The reduced chain slap and the direct feeling of power transfer are sensations only truly experienced with a simple setup.

Installation and left-right alignment require specialized tools and precise adjustment. We recommend professional installation when considering a single-speed conversion, including verification of compatibility with your frame and crank.