1. Threaded (English/BSA and Italian)

The threaded bottom bracket has been around for many years and is the most common type. The width of the shell is 68mm (73mm on mountain bikes) and is threaded either English (1.37" x 24 TPI) or Italian (M36 x 24 TPI). Most bikes are English threaded unless it is an Italian bike (Colnago, Pinarello, etc.) in which case it is likely Italian threaded.

A number of bottom bracket bearing assemblies fit the threaded shell type including square taper, ISIS, Octalink and external cup. External cup bearings are currently the most popular (see the photo below). External cup designs include Shimano, FSA and others that have a 24mm crank spindle. SRAM's Giga-X-Pipe 'GXP' bottom bracket uses external cups but the bearings taper from 24mm on the drive side to 22mm on the non-drive side.

Regardless of the bottom bracket bearings you have now it is easy and inexpensive to move your power meter to a different threaded bottom bracket type.

Threaded BB Compatible: Quarq ELSA 10R, Quarq RIKEN 10R, SRAM RED, SRAM S2275 MTB

2. BB30, OSBB and PF30

The BB30 bottom bracket was developed by Cannondale and appears on more bikes every year. It uses a 68mm wide shell and a 30mm diameter spindle, hence the name BB30. The shell itself is not threaded; instead the bearings press directly into the frame.

The most common BB30 bikes are Cannondale and Specialized. Specialized call it Oversized BB or OSBB and have an excellent guide to their bikes on their web site. Other manufacturers also use this standard. OEM BB30 cranksets include Cannondale's Hollowgram SI, SL and SISL2, and the Specialized S-Works Carbon. A BB30 crankset will not fit on a bike with a threaded bottom bracket shell.

Press Fit 30 (PF30) is a SRAM-developed version of the BB30 system where the bearings are housed in press-in plastic cups, which are in turn pressed into the frame. This system facilitates looser manufacturing tolerances and promotes improved bearing life. BB30 and PF30 bottom brackets use the same cranks.

BB30 Compatible: Quarq ELSA 10R, Quarq RIKEN 10R, SRAM RED, SRAM S2275 MTB, Quarq for Cannondale, Quarq for Specialized

• Fitting BB30 power meters in a Specialized OSBB requires spacers found in the SRAM BB30 Assembly Kit.

3. Integrated Bottom Bracket - BB86 and BB90

The integrated bottom bracket standard uses a 24mm spindle with press-in bearings. i.e. The bottom bracket bearings from an external cup system are pressed directly into the frame, eliminating the cups and threads. This system can use cranks designed for external, threaded bearing cups.

Variations on this system were developed independently at Scott, Trek and others. There is not a common name beyond "integrated bottom bracket" but the overall shell width is typically 86mm or 90mm wide so the terms BB86 and BB90 have been popularized.

Bikes with BB86 and BB90 include high end carbon models from Trek, Scott, Giant and others.

BB86/BB90 Compatible: Quarq ELSA 10R, Quarq RIKEN 10R, SRAM RED, SRAM S2275 MTB

4. BBright

BBright is a bottom bracket standard developed by Cervelo that uses a 30mm axle and press-in bearings, but the left side bearing is moved outward 11mm to allow for wider frame tubes. This promotes increased stiffness. Some newer Cervelo frames use BBright. More information on BBright can be found at bbright.net.

BBright Compatible: Quarq ELSA 10R, Quarq RIKEN 10R, SRAM RED, SRAM S2275 MTB

Contact our Customer Service team to get the BBright power meter installation sheet.

5. BB386EVO

We have tried to install ELSA 10R, RIKEN 10R and SRAM RED GXP and BB30 power meters on several bikes with BB386EVO bottom brackets without success. Please contact us before buying or trying to install a Quarq power meter on a bike using a BB386EVO bottom bracket.

SRAM S975 & CinQo Saturn - Frames with Known Compatibility Issues

The discontinued SRAM S975 and CinQo Saturn power meters will not fit the following bikes due to their oversized bottom bracket shells.

• Update Willier Cento Uno - 2010 or later. The Quarq for Rotor 3D Power Meter will work, but you must use a 2mm spacer (available in the SRAM bearing kit for the Cento 1) between the bearing and frame.
• Garneau Gennix.
• Eddy Merckx EMX-5 & EMX-7 2011 or later .
• Gary Fisher Carbon Road Cronos - 2009 and 2010 models.
• Principia C24T.
• Avanti Team Quantam.
• Basso Diamante.
• Fuji Altamira.
• Davinci Leo SL 2012.
• Simplon Serum.

If you are aware of any other frames that do not work, please contact us with the make, model and year of the frame.