Recently acquired a mid 80s fuji frame with the 414 butted tubing from someone on CL, and currently I'm in the process building it up. however, I'm having problems finding a proper cartridge BB.

The old spindle taken off is marked 3t and checking on sheldon brown's site the modern symmetrical equivalent is 130mm, (for a road/mountain triple?) the crank I have planned for this bike is a double up front and 8 in the back.

Since this bike also came with 700c wheels that were too big to fit the frame. I can only assume this was a project bike that the previous owner tried to put together but abandoned.

Which cartridge bearing bb can I use for this setup?

other than the width and threading Italian is 70 wide and 36x something and English is 68 wide by 1.37x something everythignelse is based on the crank set. what cranks are you using? buy the correct lenght English BB for it and should be OK

This is a difficult question to answer with the information you've supplied so far.

Assuming that you have a rear wheel/freehub/cassette combination that you'll be running, you'll have to measure the chainline to the center-most cog when installed. For an 8-speed, this will be in the gap between the 4th and 5th position. For a 7-speed, this will be the 4th cog.

Measure from the inner distance between the two rear dropouts, both ways. Do the math do determine the millimeters from the center of the dropout spacing (likely 63mm from the non-drive side dropout inner face) to the cog in question. This is your nominal chainline. So, for your double, you'll want to straddle this chainline for the front crankset chainrings. If you have ~4.5mm to 5mm separation between your chainrings, then, factor that into your determination of the correct chainline. Align the center of the separation with the chainline measurement from the rear.

Now to the empirical part. Let's say, for discussion, that your desired chainline for the front is 48mm. That's the goal.

Install your existing spindle (the one you've just removed) with its bearings and the cups/retainers tightened properly. No need to worry about lubrication. Install the right crankarm with chainrings and measure the chainline. From the drive side outside of the seat tube to the center separation between the chainrings, in millimeters. Add to that measurement half the diameter of the seat tube. That's the current chainline. How much is it off from your desired goal? Write it down, in mm.

Remove the drive side crank and bb spindle. measure the spindle length, taking into consideration any asymmetries (you said it was from a triple). Add (subtract) the difference between what you have and what you desire, and that's your answer, the correct spindle length for your double.

Order a cartridge of that size that fits the threading and width of your bottom bracket shell.

Does this help?
PG

hmm, I have not physically measured the threads, but the bottom bracket shell width is 68mm and the bike being Japanese made.. I'm going to assume its iso/british..I'm planning to reuse the sugino double that came with the bike.

phil, sounds like something I can measure later today, thanks for the instructions

alrite, not quite sure what i should make of these numbers

i got my hands on a 9 speed cassette so I measured from the end of the cassette to the 5th cog to be about 11mm, with a hub length of 130mm that would give me a chainline of 54mm

seat tube O.D. is 28.7mm
using a caliper the distance between the seat tube and the middle of the 2 chainrings measure 34.29..so the front chain line is 48.6mm.

does this sound right?..i remember reading on the sheldon brown website saying something about a road double should be about 43.5mm?

If 70mm try this one 5s-B - I have really been lucky with this one...

https://www.amazon.com/Bottom-Bracket...6288651&sr=8-1

I'm very interested in reading more feedback on this topic. I still get confused over ISO vs. JIS. Basically, ISO is more of an euro-Italian thing with a short taper, and JIS is most common to JP bike (JIS: Japanese Industrial Standard). You may find the model of your crank on velobase and they may tell what type taper it has. It sounds like you need an english thread 68mm BB. Now determining the length is what I would be interested in hearing others discuss. Typically a 115 or 117 should be OK for a double crank I think.
https://velobase.com/
https://www.sheldonbrown.com/bbtaper.html

zand, I'm looking for a sealed cartridge replacement, but thanks anyway

rothen, I'm more than certain that I need the iso/british 68mm BB, its the length that is confusing me. I was thinking since 130mm is the most common road hub, what bb length is everyone else using with a double?

also what variables would there be for a bike to use a 115mm length compared to a 117mm and vice versa.

I had the same questions about going from an asymmetrical spindle to a symmetrical cartridge. I was replacing an old touring bike triple with a 128mm spindle. It was 4mm longer on the drive side than the non-drive. That would be taking 2mm off the driveside and adding 2mm to the other side. Not much. I went with a 127.5 Shimano cartridge and it worked fine. The chainline is very proper. If you are going with a double crank, the length will be shorter. Image wanting the middle of the double crank, the distance inbetween the the chainrings lining up with the center cog of the freewheel. Try it with what you have if you can without tightening it down. Getting a proper chainline using math and measurements is possible. I just don't know how to do it. The difference between 115 and 117 is almost insignificant, 1mm to either side. The important thing is to not get a length so short that the inner ring rubs the chainstay.