how do i determine bottom bracket spindle length

My crank says it has a chainline of 43.5mm when used with a 68x113mm BB. Over the years, the bicycle industry has created numerous bottom bracket standards. When the bicycle is pedalled, the spindle inside the bottom bracket turns simultaneously. If I use a 68x116mm BB would the aditional 3mm need to be divided by 2 because it will add 1.5mm to each side making my chainline 45? This dimension has to do with what kind of frame the bottom bracket fits, and has nothing to do with the crank. I was thinking about getting these BB cups and getting a spindle after figuring out what length it should be. Bottom Bracket Standards and Terminology.

To determine the compatibility of a bottom bracket with a bottom bracket shell and/or crank set, two sets of measurements are taken: respectively, the bottom bracket width and bottom bracket spindle length. All the different standard dimensions can make it hard to determine what kind of bottom bracket shell your frame has and what bottom bracket bearings you need.
Unfortunately, the industry has not been clear and consistent when creating terms and names for them, sometimes creating several names for the same bottom bracket standard. The first is the part of the frame itself, usually called the bottom bracket shell.

This topic has 0 replies, 1 voice, and was last updated 1 year, 1 month ago by qagmmmcbca. If the Bottom Bracket you have isn't the right size, you will need to replace it with one that is the right size. I'm asking what I need to measure on the bike to make sure I get a length that will give me a good chainline.This is for a newer road racing frame that had no bottom bracket when I got it so I have nothing to compare it to. Shimano sometimes specs two different lengths for the same crankset. This will determine the chainline and various clearance dimensions. I was thinking about getting these BB cups and getting a spindle after figuring out what length it should be. Close the jaws so that they’re flush with each exterior edge on your pegs. I offered you additional info to help you get to the spindle length answer, in case that's what you were actually asking, and said it depended on the chainset you plan to use. Don't include those in that measurement. What length bottom bracket (BB) spindle do we recommend for your new Surly? Length: overall spindle length in millimeters.

I'm asking what I need to measure on the bike to make sure I get a length that will give me a good chainline.This is for a newer road racing frame that had no bottom bracket when I got it so I have nothing to compare it to.
). When measuring the bottom bracket, it is important to remember that it consists of two parts. some people like a wider spindle to get their feet further away from the frame.

Calculate the length of the bracket from spindle to spindle. The bottom bracket is the part of a bicycle frame around which the pedal cranks revolve.