# Brompton T5. How To Remove the FAG Bottom Bracket.



## Mr Cotter Pin (1 Mar 2021)

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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## mickle (1 Mar 2021)

Mole grips will destroy the nylon cups. You need one of these: https://www.ebay.co.uk/itm/Cyclo-Bo...-/141547754760?_trksid=p2349624.m46890.l49292


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## berlinonaut (1 Mar 2021)

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.


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## Ian H (1 Mar 2021)

mickle said:


> Mole grips will destroy the nylon cups. You need one of these: https://www.ebay.co.uk/itm/Cyclo-Bo...-/141547754760?_trksid=p2349624.m46890.l49292


That's the kind I have. You just need a big spanner to go with it.


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## mickle (1 Mar 2021)

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.


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## Kell (3 Mar 2021)

Wouldn't any 20 spline BB tool work? 

£5.99 and a big 32mm spanner or adjustable...

New Bike BOTTOM BRACKET REMOVAL TOOL Socket ISIS Shimano 20 Tooth Spline Spanner | eBay


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## mickle (3 Mar 2021)

Kell said:


> Wouldn't any 20 spline BB tool work?
> 
> £5.99 and a big 32mm spanner or adjustable...
> 
> New Bike BOTTOM BRACKET REMOVAL TOOL Socket ISIS Shimano 20 Tooth Spline Spanner | eBay


No. Because an FAG BB has a six indent lobe pattern, not a 20 spline.


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## rogerzilla (3 Mar 2021)

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.


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## Kell (4 Mar 2021)

mickle said:


> 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.


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## TheDoctor (4 Mar 2021)

The OP has a BB that doesn't have the 20 spline thing though - have a look at post 1.
A T5 is quite an old Brompton, I assume FAG changed the design at some point.


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## Kell (4 Mar 2021)

TheDoctor said:


> The OP has a BB that doesn't have the 20 spline thing though - have a look at post 1.
> A T5 is quite an old Brompton, I assume FAG changed the design at some point.



Ah.

It's not often I'm right, but I'm wrong again. 

As you were...


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## 12boy (4 Mar 2021)

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.


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## Gunk (5 Mar 2021)

I have a FAG tool but for some reason they are hideously expensive, unfortunately nothing else really works.

Happy to post it to you if you need it and you can send it back once you’ve finished with it.


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## Mr Cotter Pin (7 Mar 2021)

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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## Mr Cotter Pin (7 Mar 2021)

Hello
Mickle, Berlinonaut, Ian H, Kell, Rogerzilla, The Doctor, 12 Boy and Gunk
thank you for your contribution/s on this matter.
Very much appreciated
Mr Cotter Pin


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## Blue Hills (7 Mar 2021)

Mr Cotter Pin said:


> 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.


Can I ask where you got it from/how much?
I also have a Brommie Traveller.
Must admit that I was a bit P'd off to find a few years ago when I had a peer at it to find that they had used something so "non standard". Luckily I didn't try to bodge anything - and wasn't entirely sure what it was.
All working OK I stress - I was just thinking of taking the BB out to grease the threads.
Spare BBs are available I hope so that I can retain the cranks if the BB ever packs in?


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## berlinonaut (7 Mar 2021)

Blue Hills said:


> to find that they had used something so "non standard".


FAG type bottom brackets are the absolute opposite of "non standard". Just not as common today as they used to be. But your bike obviously has some years on the counter already.


Blue Hills said:


> I was just thinking of taking the BB out to grease the threads.


Why? There's absolutely no reason to do that.


Blue Hills said:


> Spare BBs are available I hope so that I can retain the cranks if the BB ever packs in?


No. As said before on older Bromptons you do have have an ISO bottom bracket and these are close to impossible to get hold of for some years already. For quite some years it has been replaced with JIS, you can use them with the old cranks but it is a bit off. Never change a running system... BTW: The Brompton manual recommends replacing the cranks every 5k miles.


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## Gunk (7 Mar 2021)

I’ve got a used FAG ISO BB in my parts box if anyone needs one. They’re no longer available new


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## Mr Cotter Pin (7 Mar 2021)

Hello Blue hills. I bought a PARK BBT-4 bottom bracket tool. 

From eBay seller 'biketart'. £12.49 posted.

Search for "Park Tool BBT4 - Bottom Bracket Tool - Sachs, Campag Veloce, Thun, SKF"


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## Blue Hills (8 Mar 2021)

@berlinonaut 

>>FAG type bottom brackets are the absolute opposite of "non standard". Just not as common today as they used to be. But your bike obviously has some years on the counter already.

Well I suppose after a few adventures in the outer reaches of biketech I tend to favour Shimano bits and bobs. If a standard FAG clearly wasn't a standard to last if, as I understand, you can no longer get those old bits. I have several bikes older than that brommie - no issues with their bits. Yep, mine is getting on - it's not actually done too many miles.

>>Why? There's absolutely no reason to do that.

I've always understood that it's good practice to take BBs out periodically to degrease the threads. I have definitely had one stick. Factory fitted stuff is also often I think rather lacking in grease so I always take BBs out of new bikes soon after buying.

>>No. As said before on older Bromptons you do have have an ISO bottom bracket and these are close to impossible to get hold of for some years already. For quite some years it has been replaced with JIS, you can use them with the old cranks but it is a bit off. Never change a running system... BTW: The Brompton manual recommends replacing the cranks every 5k miles.

Thanks for the info. You seem to be an expert on this stuff. If you could recommend a Shimano BB and a crankset from whoever that would fit I'd be very interested/grateful. Won't be doing until I need to obvs.

As a sign of how much I have thought about all this on this relatively lightly used bike it was only your comment on the cranks needing to be swapped every 5,000 miles that alerted me to the fact that chainrings can't be replaced. That wasn't very clever of them was it? And definitely not green. 

So down the line I'll be looking for a new crankset with a standardish BB and a replaceable chainring.

Thanks for your post.


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## 12boy (9 Mar 2021)

I have gone tens of thousands of miles on Japanese cranks, and Sugino RD cranks in particular. After many on and offs I've seen them get too worn in the area where the crank meets with the square spindle and also having the threads of the pedal insert become damaged. The pedal thread problem can occur with cross threading. Otherwise they seem bullet proof to me. A 118 Shimano U55 bottom bracket has worked well for me. I like to grease the BB threads, as well.


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## Blue Hills (9 Mar 2021)

[QUOTE="12boy, post: 6339415, member: 45924"\]A 118 Shimano U55 bottom bracket has worked well for me. I like to grease the BB threads, as well.
[/QUOTE]
Was this on a brompton traveller T5 5 speed?
I ask as I know the rear triangle is different than on more modern bromptons.


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## rogerzilla (9 Mar 2021)

A Shimano BB 113mm long works with Sugino XD2 cranks (or Spa Cycles' unbranded XD2 cranks) if you put the chainring on the inside of the spider. You must get the XD2 DOUBLE crankset, not the triple. You will need a 110mm BCD ring - 52T is reasonably easy to find.


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## 12boy (9 Mar 2021)

No, Blue Hills, it was on a 2010 and worked fine with the stock one piece, a Sugino 130 BCD RD with 54 and 38 tooth chainrings and later with a Sugino 110 BCD with a 58 and a 38.


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## rogerzilla (10 Jun 2021)

A bit of experimentation and measuring shows the old swaged crankset gives the correct chainline with a 110mm Shimano UN55, exactly as Sheldon Brown suggests (ISO crank on JIS taper sits 4.5mm further out). It seats just as well, which you'd expect as a JIS taper is really an ISO taper with the narrowest bit cut off. Total contact area will be a bit less but is neither here nor there.


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