Hello and Welcome,
I was hesitant for a long time to attempt a "one piece" to "three piece" bottom-bracket conversion. And honestly a few years ago my skill level was probably not up to doing the job. And even if I was ready to attempt one, my tool-box was not.
Above: The infamous Ashtabula One Piece bicycle Crank also know (by some) as The Boat Anchor. For many many years this type of crank has been the standard for entry level bikes in the US. It is still used today, but mostly on single speed retro style bikes.
Schwinn Bicycle Co. line sporting Weinmann center-pull brakes, (which by the way were really cool back in the day) and then you look down and see this Gawd Awful Monstrosity of a crank. I am sorry I don`t mean to offend any Schwinn purists. Hey I love them too, But What the Heck were they thinking?
bottom bracket conversion kit US to Euro pieces for fit. These are also press-in parts, if they were not you would need to get the bracket shell threaded.
rotary tool to grind it till I felt it was workable. Before pressing it into place I check the position of the piece. I do not want to run-into any tubes with any of the four bolts. This kit has arrows on it, I note the position of the arrow when I have the cup-adapter in the correct position. After applying a very light coat of grease inside the bracket-shell where I did the grinding. I am now ready to press in the piece. I start the cup by gently tapping it into place with a plastic head mallet. This is tricky, It has to be flat or going in evenly.I do not want it tilted. This took a few attempts. I only tap it in far enough to hold it in place probably about 1/32nd to 1/16th of an inch.
Bottom Bracket Installation Tool made with a piece of threaded rod two nuts and various size washers. Note: I took this pic after I started tightening the clamp/press. You would never want to tap a piece in this far. For the first side I used a larger washer on the opposite side (bigger than the housing) When I pressed in the second piece I used the brass colored washers on both sides. Making sure that the bolt holes lined-up first. I was fortunate to have the correct size brass washers on hand. They actually fit in the adapters inset perfectly. And being brass they are less likely to do any damage. They were in with some of my Dads tools I inherited. I guess Dad liked to hang onto any part he thought could be useful on some future project as well.
Gearwrench works best for this part.
Road bike crankset.
Above: I start with the drive side wrapping the threads with Teflon tape. This will help prevent creaking and make for a tighter fit. And of course protect the threads from
moisture and contaminants. There is absolutely nothing different about this three piece crank install at this point. Except that the threaded cup pieces are now recessed into the conversion pieces a little. They will be a little harder to tighten, but not real difficult.
bottom bracket spindle from the left side. I read somewhere that one restorer had trouble at the next point because the bracket shell was not square. This has been in the back of my mind since I started this. Hopefully that will not be the case for me.
thread lock on the threads before screwing the retainer nut on tightly using a socket and ratchet. You might find it easier to put the thread-lock on the nut threads.After installing the dust cap it is time to turn the frame around so I can finish this up.
BB Conversion BP American to Euro by Bulletproof can be ordered on Amazon dot com. It will actually come from Niagara Cycle. The cost is about 15.00 US.
Until next time, Please RIDE SAFE and Remember to Always RESCUE, RESTORE & RECYCLE