I currently have some old school Sugino cranks, and the chain ring I'm using has 42 teeth, and the cog at the back has 16 (not sure if this info is needed). Close the jaws so that they’re flush with each exterior edge on your pegs. The hub is at a shop being laced into a wheel now. If this information was not supplied with your crank, look it up on the net or give your local bike shop a call. 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. Always remember, the crank determines the spindle length, not the frame. Bottom Bracket Standards and Terminology. Calculate the length of the bracket from spindle to spindle. 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. Finding the correct bottom bracket for your frame can be challenging. spindle width (or length depending on your perspective) has to be wide enough so the cranks clear the frame but after that, it's kind of personal preference. Length: overall spindle length in millimeters. What chainset do you plan to use? ). The position of the front rings is in large part determined by the length of the bottom bracket spindle. The bottom bracket and spindle together form the foundation of the drivetrain on your road bike or mountain bike. Many people are not aware of how to pick the right bottom bracket that suits their needs. 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. How do I determine what bottom bracket spindle length will work with the crank to give me a good chainline? I was thinking about getting these BB cups and getting a spindle after figuring out what length it should be. Then use the chart below to help identify key crankset dimensions needed to select the correct bottom bracket for your frame. The first is the part of the frame itself, usually called the bottom bracket shell. How does one determine what bottom bracket spindle length to get? 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. Crankset Standards. This dimension has to do with what kind of frame the bottom bracket fits, and has nothing to do with the crank. The second is the component that goes inside the shell, which is often referred to simply as the bottom bracket, but is also known as the spindle. How does one determine what bottom bracket spindle length to get? 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? I would become familiar with Sheldon Brown's Bottom Bracket Size Database.It will give you a good idea of what length spindle is intended for many cranksets, and has a table showing the lengths of Japanese spindles by code (3H = 113mm etc. The chainline refers to the way the front chainwheel and rear sprocket are aligned. I presume this is a question about setting up chainline on a single-speed/fixed gear bicycle. I am using an internal 7 speed hub that says the chainline it uses is 45.3mm. To some level, the kind of a bottom bracket you prefer will be identified by the frame type, since some frames – especially carbon models beyond a particular price point – are created to utilize a form of bottom bracket and one kind only.