SQUARE TAPER BOTTOM BRACKETS

Eccentric Bottom Brackets

We manufacture several types and sizes of both eccentrics and eccentric shells.

Standard Eccentric

The standard eccentric shell is for framebuilders. It is made out of 4130 chromoly tubing. It uses 17-4 stainless stand-offs that can be welded or brazed to the shell. These stand-offs accept cupped-point set screws used to fix the position of the eccentric body.

Our standard eccentric is meant for an eccentric bottom bracket shell with an inner diameter of 2.142.” It provides 1/2" of eccentricity. A 6mm hex wrench can be used to rotate the eccentric to the desired position. The half-link eccentric provides 1/4" of eccentricity and is meant to be used with an eccentric bottom bracket shell that has an inner diameter of 1.840.” Both the standard and half-link are to be used in a bottom bracket shell with a width of 68mm. They are British threaded and compatible with many brands of bottom bracket.

Our HL30 eccentric also provides 1/4" of eccentricity. The inner diameter of the HL30 shell is 47mm - slightly larger than our half-link eccentric. It is produced in both 68 and 73mm widths. The HL30 provides more versatility than the other eccentrics. In addition to the standard functions of an eccentric, it will accept bearings for BB30 cranks. These press fit bearings have a dynamic basic load rating of over 50% greater than the standard BB30 bearings used today. (Note that when using the bearings for the BB30 cranks, the bottom bracket no longer functions as an eccentric and may require a chain tensioner.)

PhilcentricTM

The Philcentric provides 1/4" of eccentricity for OBB cranks. The Philcentric has a similar outward appearance as the OBB cups and will thread directly into a threaded bottom bracket shell (available in all threadings). The Philcentric has discrete fixed positions every 15 degrees. The maximum looseness that may be found in the chain will be no more the thickness of two business cards. The Philcentric uses the same 6805 bearings as standard OBB cups.