Bottom bracket standards
Modern Campagnolo bottom brackets
Campagnolo currently offers three types of cranks with their drivetrains.
Ultra-torque and Power-torque cups thread into traditional 68/70mm threaded shells. Over-torque cups are pressed into BB30/PF30 frames.
In 2007, Ultra-torque was introduced on all double cranksets to replace square taper systems. The bottom bracket spindle is split into two halves, where each half is integrated onto a crank arm. Ultra torque uses sealed bearing cartridges pressed onto each spindle half, and empty, external bearing cups are threaded into the bottom bracket shell using this tool. Super Record cups are required if you have CULT ceramic bearings, which are included with Super Record cranks. A wavy washer is installed onto the non drive side spindle, inboard of the bearing (see figure below). The two crank arm spindles are then inserted into the bearing cups, and connected in the center with a Hirth Joint and an over-sized bolt installed through the drive side crank (left hand threaded on Super Record). This tool is required to complete installation. Care must be taken to ensure the crank arms are installed at 180°. A retaining clip is inserted into the drive side cup to secure the bearing.
2015+ SuperRecord 4-bolt cranksets use a left-hand threaded titanium central fixing bolt.
In 2011, Power-torque was introduced on the lower end models of Athena, Centaur and Veloce. Power-torque is a two-piece crankset with the full-length spindle integrated into the drive side crank spider. This system uses different cups than Ultra-torque.
In 2012, Campagnolo released Over-torque cranksets and bottom brackets as their answer to the 30mm diameter crank technology. Cups can be pressed into modern frames with BB30, PF30 shells, although Campagnolo also makes a threaded cup set for traditional threaded frames.
Press Fit bottom brackets
Park Tool has a great article about the different types of bottom brackets on the market. Check it out here:
Square taper width, diameter, threading
Square taper bottom bracket width, diameter and threading
Road bottom brackets generally are available with either British or Italian threads.
British is more popular in the US and is widely called English threading. British threads measure 1.37 inches x 24 threads per inch.
The frame, bottom bracket shell diameter of an English threaded bottom bracket (C) , is 1.37 inches (34.8 mm).
The length, distance from one cup face to the other (B) , of a road frame bottom bracket shell that is English threaded is 68 mm.
Road frames also come with Italian threaded bottom bracket shells. Italian threads measure 36 mm x 24 threads per inch.
An Italian threaded bottom bracket shell is 36 mm wide (C ) and 70 mm in length(B ). A British threaded cup will slide into an Italian shell without catching any threads. An Italian cup is too tall to fit into a British threaded bottom bracket shell.
The length (A) of your bottom bracket spindle must be matched in length and taper to the crank arm it was designed for.
Mountain bikes almost always come with English threaded shells. The exact thread measurement is the same as road bikes, 1.37 inches x 24 threads per inch. However, mountain bikes come with two different bottom bracket shell lengths; 68 or 73 mm. 68 mm is the most popular but 73 mm is catching on. Both often require different bottom brackets even though spindle length and cup threading is the same.
Square taper compatibility - length and tapers
All cranks must be matched with a specific length bottom bracket spindle. Triple cranks or frames with oversize seat tubes require slightly longer bottom bracket spindles.
Shimano and almost every major bottom bracket maker have traditionally used the same spindle end cross section of 12.9 mm and two degree taper. Campagnolo uses the same two degree taper but has a smaller starting cross section of 12.7 mm.
A Shimano crank arm will bottom out on Campagnolo spindle. A Campagnolo crank arm will not draw far enough onto a Shimano spindle.
Phil Wood now produces both Campagnolo and Shimano taper bottom brackets in a wide variety of lengths. Phil bottom brackets are exceptionally well made and usually last for 30,000 miles without maintenance.