Jan 28, 2011

Unsticking a Seized Bottom Bracket

Few things can be quite as frustrating as a stuck part. It shuts down the whole maintenance operation until lubricants, greater force or destruction frees things again.

The last time I rode my winter bike, it felt like it was pedaling poorly. Closer investigation revealed that the sealed bottom bracket was one its very last legs. If felt like there were rocks in it, and it had to be replaced because the sealed units are not really meant to be user-serviceable.

The sealed cassette bottom bracket is usually a really simple operation, but I quickly realized that my bottom bracket was seized up in the frame. Every time I attempted to turn the cartridge out of the frame, the bottom bracket socket would cam-out of the splines before the cartridge would break free. Dammit. I screwed around with this a few evenings trying to free it with Liquid Wrench and percussive blows, but it was clear that I was going to round the splines if I kept at this much longer.

Pedro's makes a tool for just this problem, so I ordered one up from my LBS, but it won't be in until sometime next week. There's no way I could ever leave this alone until then, however, so I went to the hardware store to devised my own DIY tool and finish this.

One 8m 1.25 bolt and a few washers set me back $1.12. The spacing to get this tight enough to hold the socket in the splines was a process of trial and error. It turned out that using an old freewheel removal tool as a large spacer and fine tuning it with washers was the winning combination.

The 8m bolt and spacers were threaded through the removal tool (with the wrench already on the tool) and then carefully screwed nto the spindle of the bottom bracket, like so.

Once this was holding the removal tool in place I was able to give the wrench a few good baps with a hammer and break the bottom bracket free. Installing the new one was a piece of cake after that.

I am still going to pick up that Pedro's tool because the spacing would be so much simpler, but in the event anyone else runs into this problem and doesn't want to buy a specialized tool,  this little trick is pretty easy and useful enough to make it worth sharing.

Thanks to Kyle, Andrew, Liam and Bob for their helpful advise on this one. Success!

EDIT - I am getting quite a few hits on this post. If this was helpful, or if you have something to add, kindly post a comment and let the world know.


  1. OH nice. I didn't know there was a tool for this sort of thing. That's really great to know. When I ran into a stuck bottom bracket (old loose bearing and cup style), I took it to Nokomis Cycle and they worked their magic on it and only charged me $5. I take all my little chores like that to them.

  2. Nice. Reminds me of my "hardware store" headset press.

  3. Nice one, never knew this tool existed until I had the same problem.