Currently in the process of restoring an old MBK (Motobecane) Mirage 18 road bike made some time between 1985 and 1988.
Around the bottom bracket there seems to be a plastic cover that I can’t figure out how to remove. Since it’s plastic I’m also hesitant to put any pressure with an adjustable wrench etc. on it especially considering that there’s already some marks which I assume are from somebody else’s attempts at doing the same.
Do you know of any way to remove this bottom bracket or alternatively how to properly get the bottom bracket greased without having to remove it? I poured some mineral oil in it from both sides and while it helped somewhat, it still doesn’t feel nearly as good as I’d like it to feel and it would also be the only part on the bike that I couldn’t remove.
The writing on it reads “THT ⌀34HS” and it’s made FAG Germany.
GenericName187 on
I think you have a 40mm Thun Thomson bottom bracket. I believe these are pressed in, not threaded.
2 Comments
Currently in the process of restoring an old MBK (Motobecane) Mirage 18 road bike made some time between 1985 and 1988.
Around the bottom bracket there seems to be a plastic cover that I can’t figure out how to remove. Since it’s plastic I’m also hesitant to put any pressure with an adjustable wrench etc. on it especially considering that there’s already some marks which I assume are from somebody else’s attempts at doing the same.
Do you know of any way to remove this bottom bracket or alternatively how to properly get the bottom bracket greased without having to remove it? I poured some mineral oil in it from both sides and while it helped somewhat, it still doesn’t feel nearly as good as I’d like it to feel and it would also be the only part on the bike that I couldn’t remove.
The writing on it reads “THT ⌀34HS” and it’s made FAG Germany.
I think you have a 40mm Thun Thomson bottom bracket. I believe these are pressed in, not threaded.
https://www.sheldonbrown.com/cribsheet-unthreaded-bottombrackets.html
I could be wrong, these are not common in America. Here is more information on installing
https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/publication/downloads_18/wl_05114_5_de_en.pdf
An older bike shop in Europe may have more knowledge of these