American Custom Bicycles in Steel, Titanium and Ti/carbon mix

Eccentric Bottom Bracket


What is an Eccentric Bottom Bracket?

An Eccentric Bottom Bracket (EBB) is a device used to add tension to a bike chain or belt. A traditional bottom threads into an EBB in an off center location, which allows tension to be increased or decreased by swiveling the EBB clockwise or counterclockwise. When the appropriate tension is achieved, the EBB is held in place by expander bolts inside the unit.

What is the difference between an EBB and sliding drop outs?

The EBB adjusts chain tension at bottom bracket, allowing the frame to have traditional horizontal drop outs.

How much do adjustable drop outs cost?

$400 per frame.