Need help identifying bottom bracket
5 min read
Asked by: Maurice Welch
How do I know which bottom bracket model I have?
To find out the size of bottom bracket needed, measure the inside of the bottom bracket shell in your frame, it will be 73mm, 70mm or 68mm. Some older frames may have Italian threaded bottom brackets, instead of the more modern English.
How do I know if my bottom bracket is Italian or English?
The key difference is in how the two thread into the bottom bracket shell. Like pedals, one side of a BSA standard bottom bracket shell is reverse (left) threaded, while both sides of an Italian standard bottom bracket shell are regularly (right) threaded.
What do the numbers on a bottom bracket mean?
The numbers ranging from 86 to 132 refer to the nominal width of the shell in millimeters, which is not related to the press fit of the bearings. These bottom brackets will vary in the width of the dust sleeve used for that different widths.
Are all bottom brackets compatible?
In general terms, most cranksets can be fitted to a variety of bottom bracket shells, though much of this compatibility depends upon the availability of suitable hardware (see next section). Any incompatibilities that do arise are often related to the length and/or diameter of the crank axle.
Is BB92 the same as PF92?
The frame’s bottom bracket shell inner diameter is 37mm. A bearing with an OD of 37mm is pressed directly into the frame. Trek is moving away from the BB90/95 system to what they call PF92, which is the same as a BB92 (41mm ID shell and 92mm width).
How many types of bottom brackets are there?
two main
There are two main types of bottom bracket design, one with a threaded shell which the bearings screw into, or a press-fit design which the bearings press into the shell.
What is a British thread bottom bracket?
The common threaded bottom bracket uses cups or adapters with the thread specification of 1.37″ x 24 threads per inch (approximately 34.8mm diameter). The most commonly used term for this standard is “English” threading, sometimes abbreviated as ENG.
Do bottom brackets have left hand thread?
The common threading for bottom bracket shells is called “English.” The left-side cup is a right-hand thread direction, which tightens clockwise and removes counterclockwise.
Will a 68mm bottom bracket fit a 70mm shell?
No. There are two different tapers, several different threads and several different lengths. Different bottom bracket shell widths.
When identifying a bottom bracket type what are the critical dimensions to measure?
The two major dimensions that differentiate bottom brackets of similar types are the shell width and spindle diameter.
What is the difference between BB30 and BSA?
BSA is English standard and have screw thread inside the hole ,usually use in shimano,while BB30 is Italian standard and don’t have screw thread, usually use in CP.
What is the difference between BB386 and BB386 Evo?
A standard 68mm BB shell width allows a down tube or seat tube diameter of around 63mm maximum. The BB386EVO system allows a much more generous amount of area, up to around 83mm.
What is the difference between BB92 and BB86?
BB86 vs BB92? No difference. They are one and the same bottom bracket. Well, BB86 refers to road bikes with their 68mm BB shell; BB92 refers to mountain bikes with their 73mm BB shells.
Are Shimano bottom brackets interchangeable?
All Shimano Hollow-Tech II road bottom bracket cups are interchangeable, that is they all have the same bottom bracket shell threads, fit in same shell width, have the same axle diameter and overall width.
What does BC1 37×24 mean?
What Type of Bottom Bracket do I Have?
What is the difference between BB30 and BSA?
BSA is English standard and have screw thread inside the hole ,usually use in shimano,while BB30 is Italian standard and don’t have screw thread, usually use in CP.
What is the difference between BB386 and BB386 Evo?
A standard 68mm BB shell width allows a down tube or seat tube diameter of around 63mm maximum. The BB386EVO system allows a much more generous amount of area, up to around 83mm.
What is a 68 73 bottom bracket?
The 68mm and 73mm dimension measure the width of the bottom bracket on the frame of the bike with no BB installed, simply the width of the shell. Most road bikes that use a threaded bottom bracket measure 68mm wide and most cross country/trail mountain bikes measure 73mm.
Are Shimano bottom brackets interchangeable?
All Shimano Hollow-Tech II road bottom bracket cups are interchangeable, that is they all have the same bottom bracket shell threads, fit in same shell width, have the same axle diameter and overall width.
How do I know what crankset fits my bike?
The two most important factors are axle diameter and crank length.
- Axle diameter: The two common axle diameters are 19mm and 22mm, so check before you buy that your bottom bracket is compatible. …
- Crank length: This is measured from the centre of the bottom bracket axle to the centre of the pedal axle.
What does JIS mean on bottom bracket?
the Japanese Industrial Standard
J.I.S. is the Japanese Industrial Standard, and is generally used on square taper cranks made in Asia. All of the common black spindles identified with standard numbering use the J. I. S. taper. Many of these have a threaded boss for a nut on each end, rather than being hollow and threaded internally for a bolt. J.I.S.