Brompton T5. How To Remove the FAG Bottom Bracket.

Hello Everybody,

RE: FAG, Germany, BSA.AA, 1.37"x, 24Tpi-, RH (This is what is stamped on the plastic cover)

I have a Brompton T5 and want to remove the plastic covers (see picture below) that hold the bottom bracket.

I'm not sure but think the correct tool to do so would be a Park BBT-4, is that correct?

And is there another way of doing the removal which would not involve having to buy the tool (I can't think of any except maybe my mole grips but that would be crude)?

Your thoughts on this matter is much appreciated.

Thanks in advance.


Safe and Happy riding.
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Mole grips will destroy the nylon cups. You need one of these:


Senior Member
Berlin Germany
This is what the correct tools for the job look like.








For one-time use buying a tool is probably not really worth it. You could use cheaper tools or even gaspipe pliers if you don't mind destroying the old bottom bracket but there's a good chance that you may just destroy it but not be able to remove it and have at the same time sucessfully hindered the proper tool from working. So I'd preferably go to a workshop if you have the possibility - the removal is a one minute job and the FAG tool is very common with traditional workshops. If you don't have a workshop around a cheap tool could be the second best choice, though even that may harm the old bottom bracket.
A bike shop is going to charge you £10 to £20 to remove the old BB. The tool costs +/-£10. In general I like to support my local bike shop, but this is a no brainer. Buy the tool. And then sell it afterwards if you think you'll never use it ever again.


Legendary Member
Don't fit another FAG one if you can help it. They tend to get stuck. I have a nasty feeling it might have an ISO taper, though, and the RH length is fairly critical. Yiu can mess with rear chainline by moving the spacing washers provided for this purpose, but not by much. The crankset has an unusually large Q-factor to clear the rear triangle when folded.


Über Member
No. Because an FAG BB has a six indent lobe pattern, not a 20 spline.
Going by the picture posted above, I'd say it has both. Hence the question.



Casper WY USA
I like my BBs to have 2 metal cups. I have overtorqued the left side cup on Shimano BBs and cracked them. My OCD wouldn't abide the cup being not flush with the bike. I repaced my FAG BB with an all metal UN55 Shimano 118mm fairly early on as it creaked. Not having the proper tool a Visegrip was used, which trashed the plastic. BTW the original was ISO, as was the one piece crank but the Shimano is JIS. Per Sheldon, ISO cranks work fine with JIS spindles although the reverse is not so. In my case he was right.
Mr Cotter Pin

Mr Cotter Pin

Hello Gunk,
Thank you for your kind offer to lend me your FAG tool.
I have bought one online and it has just arrived.
I did so before you posted.
This community is very considerate.
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