Bicycle bottom bracket with tool and PVC pipes

Running out of drawing boards to revert to

I’ve missed out on a weekend of riding (and several nice weekdays besides) since my last loop around Tokyo. I’ve been struggling since then to replace Kuroko’s crankset and bottom bracket with this beauty from Sugino:

Sugino crankset after chainring replacement
Sugino crankset after chainring replacement

The hold-up in this process is removing the bbinfinite bottom bracket that was my latest (and now last) attempt to fit a 30mm spindle for the ill-starred FSA crankset into a bottom bracket shell designed for a 24mm spindle (such as the Sugino, and Kuroko’s original Shimano 105).

bbinfinite bottom bracket and tool
bbinfinite bottom bracket and tool

Memory is a funny thing: it’s not until I went looking for that post that I realized it has been less than three months since I installed the bbinifinite part, and it was already giving me trouble. But as the great Hambini points out, what I was trying to do isn’t a good idea even if several makers offer ways to accomplish it.

Bigger hammer

Shattered bbinfinite press tool

After several attempts to hammer out the the bbinfinite BB as it is came to naught, and using the installation tool together with a bearing press just resulted in a shattered installation tool, I set about building up a war chest before the next attempt. I got several cans of compressed air to cool down and contract the BB, and a heat gun to expand the BB shell — the part of the frame that holds the bottom bracket. And then I got serious and added a Park Tool bearing press and removal tool.

Park Tool bearing press, removal tool and hacksaw on a wood floor
Bearing press, removal tool and hacksaw

I also got several pieces of PVC pipe. My idea was to remove the bearings one by one, and then use the PVC together with the bearing press to push the remaining sleeve out of the bottom bracket shell. The first step was to cut a larger diameter PVC pipe to fit snugly around the frame, taking the place of the shattered installation tool. It took me a good 10 minutes or so with the hacksaw to achieve a passable fit.

Hacksaw and PVC
Hacksaw and PVC

PVC stub fitted to bicycle bottom bracket
Happy with that

Once that was ready, I set about removing the existing bearings with a hammer and the bearing removal tool.

Bearing removal tool in bicycle bottom bracket
Still making good use of the hammer

The spread of the removal tool’s flanges isn’t really enough for this bearing size, so I had to move the tool from one side of the bearing to another as I hammered on the other end. At first I didn’t seem to be accomplishing anything, but after repeated whacking around the circumference of the bearing, it popped out. Amusingly, the bearings felt fine after I’d removed them and employed the ultra-precision testing method of rolling them between thumb and fingers.

Here’s where things go pear-shaped

PVC pipe inserted through bicycle's vacant bottom bracket
It isn’t supposed to do that

I was counting on the second PVC pipe to snug up against the end of the BB sleeve that remained in the shell, and I’d made a couple of efforts to find a pipe that would be just the right size. Unfortunately, the sleeve was much thinner than I had counted on, and the PVC just slid right through from one side to the other. The sleeve is so thin and fits so flush to the BB that I had difficulty getting the bearing removal tool flanges to catch on it.

I spent the next 15 minutes or so hammering on the edge of the sleeve with the bearing removal tool and a screwdriver, attempting to get the lip to curl enough so that it would catch the PVC pipe. I managed in the process to hammer the tip off the handle of the screwdriver. Finally I raised just enough of a lip that the PVC pipe caught on it, and I decided to give my impromptu bbinfinite removal press a go.

Bicycle bottom bracket with tool and PVC pipes
Improvised BB tool disaster

It took some doing to get all the pieces aligned and ready to go, but finally it all snugged up and I started turning the handles to add pressure. It all started pressing together more or less smoothly. There was enough resistance to let me know that the PVC wasn’t simply passing right through the BB sleeve again. After pressing things together for a good couple of centimeters, I backed off the handles to inspect my progress.

And that’s when I discovered that PVC had indeed passed inside the BB sleeve, instead of pushing the sleeve out of the shell. But the PVC was now firmly wedged inside the sleeve, with the lips I had created in the sleeve gouging deeply into the PVC and holding it firmly in place. I gave it a few tugs, but it wasn’t going to move easily.

The better part of valor

At that point I decided to call it quits for the day and retire to the drawing board. I was pretty well worn out from my efforts up to this point, and it was obvious that this strategy wasn’t working. I put Kuroko back in the workshop stand and cleaned up my tools.

I’m going to sleep on it before proceeding, but I think my next step will be to continue attacking the sleeve with the bearing removal tool and screwdriver (or maybe a proper chisel) until I can raise enough of a lip to allow me to cut the sleeve free (or whack it out of shape enough that it can be pulled out). There’s a small screw hole in the bottom of the BB shell (which you can see in the photos above) which I can hammer a screwdriver through to attack the sleeve from the middle as well. I’d previously contemplated whether I would have to hacksaw the sleeve out, but it’s far too snug to the BB shell for that. I’d be sure to damage the frame. (As it is, I’m likely to scratch up the shell more than a little bit with the prying and chiseling. But that shouldn’t be a big issue unless I actually distort the shell.)

Trying to resist the temptation to consider solutions that involve a welding rig …

Related posts






Leave a Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.

Recent posts