Stripped thread Brompton BWR hub

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Bryan Attewell
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Joined: 31 Aug 2019, 9:18am

Stripped thread Brompton BWR hub

Postby Bryan Attewell » 31 Aug 2019, 9:25am

Hi

The gear selector chain on my wife's 6 speed BWR Brompton won't tighten into the hub, the threads catch but it is possible to pull the chain out. The threads on the selector chain appear OK so I fear an internal fault. Is it possible to buy a replacement internal component and is this a DIY job? I'm reasonably competent at bike repairs but have never stripped a hub gear.

Brucey
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Re: Stripped thread Brompton BWR hub

Postby Brucey » 31 Aug 2019, 9:35am

you probably need a new toggle key. The one from the current AW hub (HSA295 I think) is the same part as is used in a BWR. It is cheap enough to buy and only slightly tricky to fit; unlike older versions of the AW I think that you can replace the toggle key from the right side, without dismantling the whole hub. You just need to unscrew the RH cone, then remove the driver, clutch spring and the sliding clutch. The key will then be accessible, using a pair of tweezers.

If you measure the ID of a new key and the OD of a new control rod, you will realise that there is only a few thousandths of an inch of engagement between the two. They mostly are caused to fail when folk think the control rod needs to be screwed tightly into the key. If in any doubt then a new control rod is a good precaution; if the thread is even slightly undersize it may damage a new key even.

cheers
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Mick F
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Re: Stripped thread Brompton BWR hub

Postby Mick F » 31 Aug 2019, 9:48am

Hub gear stripping:
Remove the left side bearings completely. Cone, locknuts, spacers, the lot.
Take the sprockets off and any spacers etc.
You'll see the ball ring has two notches.

You'll need a strong hard punch and a nice hammer.

Stand the wheel up and give a notch on the ball ring a few hard accurate blows, then rotate and do the same to the other notch. It unscrews anti-clockwise of course.
It's a two-start thread and you should refit it so it goes back in the same orientation. Mark the ball ring and the hub with felt pen perhaps.

Eventually, it will shift.
Unscrew the unit and remove it as a complete unit.

Unfamiliar with the internals of the BWR, so can't advise further.
Mick F. Cornwall

Brucey
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Re: Stripped thread Brompton BWR hub

Postby Brucey » 31 Aug 2019, 9:52am

Mick F wrote:….Unfamiliar with the internals of the BWR, so can't advise further.


you don't need to do any of that with the current AW or BWR hubs, if you only want to change the toggle key.

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

2Phat4Rapha
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Joined: 1 Dec 2010, 1:58pm

Re: Stripped thread Brompton BWR hub

Postby 2Phat4Rapha » 31 Aug 2019, 10:01am

I'm in SW London and could do it for you if nearby.

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Mick F
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Re: Stripped thread Brompton BWR hub

Postby Mick F » 31 Aug 2019, 10:40am

Brucey wrote:
Mick F wrote:….Unfamiliar with the internals of the BWR, so can't advise further.


you don't need to do any of that with the current AW or BWR hubs, if you only want to change the toggle key.
Ok.
Fair enough! :D
Mick F. Cornwall

philvantwo
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Re: Stripped thread Brompton BWR hub

Postby philvantwo » 31 Aug 2019, 12:48pm

Is this the job where you've used an empty steak and kidney pudding tin Mick F?
[color=#FF0000][/color]

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Mick F
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Re: Stripped thread Brompton BWR hub

Postby Mick F » 31 Aug 2019, 5:01pm

Now that's a completely different subject! :lol:

Undoing the ball ring usually consists of using a hammer and punch.
Sturmey Archer in their wisdom produce a spanner.
Trouble is, the spanner isn't man enough for the job, so reversing the issue, it's better to fit the spanner in a vice and turn the wheel instead.
The trouble is, the spanner slips off, so using a big tin with a suitable hole in the end, you can screw on the wheelnut to hold the tin tight over the spanner to hold it on firmly.
Turn the wheel, and the spanner doesn't come off as the torque increases.

Better IMHO than hitting anything with a hammer.
Back in my day, we called it "hammer mechanics". :wink:
Mick F. Cornwall

Brucey
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Re: Stripped thread Brompton BWR hub

Postby Brucey » 31 Aug 2019, 6:11pm

Mick F wrote:….Better IMHO than hitting anything with a hammer.
Back in my day, we called it "hammer mechanics". :wink:


Sometimes this is the best way. Its what SA recommended for over 70 years.

1972 instructions here

http://www.sturmey-archerheritage.com/files/view-1046.pdf

FWIW I have never seen a working bike mechanic use a spanner on a SA ball ring.

Not that you need to remove the ball ring to do the OP's repair.

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

Bryan Attewell
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Re: Stripped thread Brompton BWR hub

Postby Bryan Attewell » 1 Sep 2019, 7:15am

Brucey wrote:you probably need a new toggle key. The one from the current AW hub (HSA295 I think) is the same part as is used in a BWR. It is cheap enough to buy and only slightly tricky to fit; unlike older versions of the AW I think that you can replace the toggle key from the right side, without dismantling the whole hub. You just need to unscrew the RH cone, then remove the driver, clutch spring and the sliding clutch. The key will then be accessible, using a pair of tweezers.

If you measure the ID of a new key and the OD of a new control rod, you will realise that there is only a few thousandths of an inch of engagement between the two. They mostly are caused to fail when folk think the control rod needs to be screwed tightly into the key. If in any doubt then a new control rod is a good precaution; if the thread is even slightly undersize it may damage a new key even.

cheers


Many thanks for that, I think that you have hit the nail upon the head! Thanks also to everyone else who has suggested solutions.

I managed to dig out this video https://www.youtube.com/watch?v=TRDCAQP1EyI which shows the disassembly process as you have described, it doesn't look to be too bad!

Any idea where I can buy the two parts, toggle key and control rod?

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Mick F
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Re: Stripped thread Brompton BWR hub

Postby Mick F » 1 Sep 2019, 7:34am

Bryan Attewell wrote:Any idea where I can buy the two parts, toggle key and control rod?
SJS have everything.
https://www.sjscycles.co.uk/hub-spares/ ... ey-hsa124/
As for the control rod, there are many sorts. They have a number on them.

They do a Brompton one.
https://www.sjscycles.co.uk/search/?ter ... 0indicator
Mick F. Cornwall

Bryan Attewell
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Joined: 31 Aug 2019, 9:18am

Re: Stripped thread Brompton BWR hub

Postby Bryan Attewell » 1 Sep 2019, 8:37am

Mick F wrote:
Bryan Attewell wrote:Any idea where I can buy the two parts, toggle key and control rod?
SJS have everything.
https://www.sjscycles.co.uk/hub-spares/ ... ey-hsa124/
As for the control rod, there are many sorts. They have a number on them.

They do a Brompton one.
https://www.sjscycles.co.uk/search/?ter ... 0indicator


Thanks Mick!

Brucey
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Re: Stripped thread Brompton BWR hub

Postby Brucey » 2 Sep 2019, 12:30am

Bryan Attewell wrote:
Mick F wrote:
Bryan Attewell wrote:Any idea where I can buy the two parts, toggle key and control rod?
SJS have everything.
https://www.sjscycles.co.uk/hub-spares/ ... ey-hsa124/
As for the control rod, there are many sorts. They have a number on them.

They do a Brompton one.
https://www.sjscycles.co.uk/search/?ter ... 0indicator


Thanks Mick!


HSA124 is the wrong part for a BWR hub. You want HSA295 as previously specified.

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

Brucey
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Re: Stripped thread Brompton BWR hub

Postby Brucey » 2 Sep 2019, 10:00pm

Here's a later set of instructions for a SA hub (old style pre-NIG AW) and even after they would sell you a spanner, they still said 'or use a hammer and punch'.

http://www.sturmey-archerheritage.com/files/view-133.pdf

IME on a machine with large wheels that has seen a bit of hard use, it would need to be some spanner to shift the ball ring. Not so bad on a small-wheeler.

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

rogerzilla
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Re: Stripped thread Brompton BWR hub

Postby rogerzilla » 8 Sep 2019, 11:26am

On Sachs Torpedo 3-speeds, the key often snaps in half. This immobilises the bike as freewheeling causes the chain to tangle.

Knock-off SA indicators often won't thread into a good key becauae the tapered thread on the indicator is so badly forned. There's a reason why some stuff is cheap, and most of it ends up on fleaBay.