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.
It bothered me the most that these were used on the Schwinn Continental(ABOVE) and also some of the early (Made in Japan) Schwinn 10 speeds. But especially the Continental. I mean here was the "flag-ship" of the
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?
Above: I don`t have a Continental right now so I decided to use this Ross Adventurer. This by the way is the third one of these I have restored. All of them the same color and all with the Ashtabula style crank. OK time to Fast-Forward.
Above: The first order of business is to remove the crank bearing cups. These are pressed in so you have to punch them out. You punch these out from the opposite side, I`m using a large screw-driver. Something with a blunt-end would be better than using a screw-driver. You want to tap them out evenly as possible. So tap a few times then move your driver or punch-out tool directly across from there. Do this top and bottom and side to side if necessary.
Above: Now clean-out the bracket-shell and check for damage or rust. Sand or file off any burs you feel, Do this the same depth as the thickness of the conversion piece. You may want to sand off the paint the same depth as well.Now you are ready to check the
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.
Above: This is the conversion kit I will be using. Notice it is marked L-left and R-right. Before I continue: You probably should have these pressed in at your local bike shop.Installing these without the correct tools it is likely that the kit and or housing will be damaged. Having said that, My next step is to take the kit apart. This particular one has 4 long bolts. Some have only three.
Above: In my case the conversion kit was a little too big to fit my bracket shell. I used my Dremal type
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.
Above: After experimenting with a Vice with blocks of wood then a Giant C-Clamp with wood blocks I finally came-up with this.
Above: My improvised
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.
Above: After pressing in the first side I noticed one of the "excess' tubes inside the bracket shell was partially blocking one of the bolt holes. I managed to grind it down with my "Dremel like" tool. Funny thing, When I first got the Dremal like tool I thought to myself "This thing is going to be useless". Wow was I wrong about that, it really saved me on this installation.
Above: A top view of the second piece being clamp/pressed into place. To tighten the press, I just hold a wrench on the back-side nut and tighten the front nut with a another wrench. A
Gearwrench works best for this part.
Above: Obviously with all the grinding and sanding going on I had to keep cleaning out the bracket shell. You certainly do not want a bunch of metal shavings anywhere near your bearings. I used Simple-Green cleaning wipes to keep the shell clean. Now the bracket conversion is complete. Now I am ready to install a lighter, better-looking and more modern three piece crank set.
Above: While searching the shop/garage I found a Ross Carrera mixte that I had purchased basically for the wheel-set. I eventually used the front wheel on the fixed gear build. I am pleased that the donor bike is also a Ross, I will be able to make some up grades while staying true to the brand. Here I am getting ready to degrease the bottom bracket bearings, cups and spindle. After that I will polish-up and assemble the
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.
Above: Now that the drive side cup is in place I will turn the frame around and install the
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.
Above: The left side went together without a hitch. As always I lightly coated the entire bracket spindle with grease. Then I packed the bearing cartridges with grease. After that I placed the drive side bearing on the longer end of the spindle with the exposed side of the bearings facing outward. Then the left side bearings go on facing me. Next I slide the spindle into place. When the bearings make contact with the outer cup I always twist the spindle a little to make sure the bearings are riding in the cup smoothly. Then I carefully slide the left side cup into position while keeping the spindle in place. After I start screwing the cup into place I stop and wrap the threads with Teflon. Then just tighten until I feel no play or grind. Then screw the lock-ring on to hold everything in place.
Above: As I mentioned before the lock-ring and cups are now recessed a little. So I have to finish tightening it with a screw driver because it is in to far for the lock-ring wrench to work properly. It`s not a big deal, we did them all this way when I was a kid. Before I turn the frame around I will install the left side arm.
Above: For good measure I put a little
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.
Above: At this point I have polished-up the crank and re-assembled it. It goes on the same way with a little thread-lock on the threads.
A Quick Tip: Use a penny and needle nose pliers to remove and tighten dust caps. I have never found a better way to do this. The cheapest tool I own, it only cost me a penny!
Above: A nice comparison shot. As you can see the old Ashtabula one piece crank on the floor. Anyone want to buy a good
boat anchor?
UPDATE: The Above
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
Cheers,Hugh
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