Hi everyone,
I have what I think is an old Morrison road bike from the 80's (I'm not completely sure as I bought the bike already painted) and I have stripped the tread in the crank, rendering it useless. After a lot of searching, I finally found some second hand cranks in good condition that fitted, only to have them break again after 6 months.
I am fairly hard on my bike, but I would expect cranks to last a little longer than that, thats why I am looking to replace the bottom bracket. but its an unusual system and it doesn't appear to simply screw out.

Can anyone tell me a little more about this bottom bracket and how to replace it?

Thanks.

(I will try to attach some pictures later)

If you twist this with the same tool as I am using, you will achieve satisfaction. Betcha that would make more sense with a picture or two, would it not?

The point is, you have to supply pictures (like this one) and a detailed description, if you hope to get quality answers.



I am aware of a few bottom brackets, such as this work of art (not) on an old Chiorda, that might be what you are talking about but without some more input from you, it will be impossible for me, or anyone else to be much help.

So, hope you can find some good clear pictures for us to work with. And, by the way, welcome to the Bike Forums.

Thanks for the help, sorry I haven't managed to post any pictures yet, my first attempt at attaching failed and I have been very busy with my studies lately. I hope these pictures do attach (and appologies for the low quality)

I believe what you have there is/was the Shimano FFS (front free wheel) system, which did not prove to be a success for the Big S. I'm afraid I have nearly zero experience with that product (and want to keep it that way) so can't offer you advice as to whether it can be saved, but if the BB shell has conventional threading (maybe) I'd replace it with a conventional BB and crankset. I'm sure somebody here (or in the mechanics forum) can tell you what your options are.
You can do an archive search here (as well as checking Sheldon Brown's site) for more info on the FFS.