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Bicycle Frame Building Components



Our office is closed on Thursday, November 26th and Friday, November 27th for the Thanksgiving holiday.

Please place your order online and we will process it when we return on Monday, November 30th.


Introducing the T47 Bottom Bracket

We are excited to introduce the T47 bottom bracket, a joint effort between several American bicycle and component manufacturers:  White Industries, Chris King Precision Components, Argonaut Cycles, Engin Cycles and Paragon Machine Works.

T signifies THREADED, and 47 is the MAJOR DIAMETER of the thread.  Like the venerable English threaded bottom bracket, a standard for decades, the T47 has right and left hand threads and can be supplied in a variety of widths.  However, this new bottom bracket features a finer thread pitch of 1 mm and a larger diameter of 47 mm.

The larger diameter allows for larger diameter bearings in both internal and external applications, a requirement for 24 mm and 30 mm crank spindles.  Frame building materials have evolved from steel to aluminum, carbon fiber and titanium, and frame tubing diameter has increased.  A corresponding larger bottom bracket shell makes it far easier to join these large diameter tubes.

The threaded bottom bracket has stood the test of time as a secure and trustworthy method of assembly.  Easily serviceable by the average rider or shop personnel, threaded bottom bracket shells rarely creak or make noise, a common problem with modern bottom brackets.  Since the T47 is a modernized version of the English bottom bracket, consumers and bike shops are already familiar with how it works.

The T47 could potentially replace all other BB standards, reducing inventory for builders, bike shops and manufacturers alike.  Any PF30 eccentric bottom bracket will fit in the T47.  Future innovations in crank spindles and bottom brackets can likely be accommodated.

The design is open, available to anyone without permission or royalties.  It is not patented or trademarked.

We have a limited number of steel and titanium 69 mm (BB0040, BB2040) and 74 mm (BB0042, BB2042) T47  bottom bracket shells available for sale; more will be available the week of November 23.   Frame and bicycle manufacturers will need the correct taps to utilize this new bottom bracket; these will be available from White Industries and PMW late 2015.


BB2042 (PDF)

BB2042 (STEP), right click, "save as"


Components for Flat Mount Hydraulic Disc Brakes

Hydraulic disc brakes have become a standard feature on mountain bikes, and are now gaining popularity on road bikes.  The newest disc brake standard is a road-specific flat mounting system developed by Shimano.  The rear brake sits flush to the frame and is mounted inboard on the rear triangle, with the brake caliper directly mounted on the frame.  This offers a cleaner and more minimalist appearance, and allows a more compact packaging of the brake caliper.

The bolts thread into the bottom of the caliper, rather than threading in from the top as is the case with post mount brakes. At the chainstay the bolts no longer thread into inserts in the frame, but pass through the chainstay from the bottom.  Because the bolts thread in from the bottom of the caliper, the front brake must be used with a slim adaptor. 

We are excited to have embraced this new standard and are in the process of expanding our selection of compatible parts.  Our newest PolyDrop inserts work with flat mount disc brakes for a 140 mm rotor.  They are available for 10 mm (PA462, PB462, PA464, PB464) and 12 mm skewers (PA466, PB466, PA468, PB468), with and without eyelets.  We will eventually expand our line of products to include other flat mount rear dropouts in titanium, steel, and stainless steel.  We will also offer stand-alone flat mounts for all of our round dropouts.

Check our homepage for product updates.