How do I tighten this bottom bracket?

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asinus
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How do I tighten this bottom bracket?

Postby asinus » 20 Oct 2019, 2:17pm

"It's a bottom bracket, but not as I know it".
My wife's pedelec has a bottom bracket of a type I've never seen before, and there's play in the bearings, and there's play between the chainwheel and the axle. See pictures to make description clearer.
It looks as if it has external cups, but a standard solid square taper axle. The chainwheel is attached, but not tightly, to the axle but not the crank. It seems to be held on by a circlip and there's a ridged ring as well on the outside of the chainwheel at the axle. On the left hand side there's what looks like a dustcap over the bearing but it's smooth on the outside, i.e. not suggesting that it's meant to be turned or tightened.
I suspect that it's an oriental imitation of an external BB, of unknown quality - but how do I tighten the chainwheehl on the axle, and the bearings??
IMG_20191019_225716.jpg
IMG_20191019_230022.jpg
IMG_20191019_225838.jpg

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Mick F
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Re: How do I tighten this bottom bracket?

Postby Mick F » 20 Oct 2019, 3:04pm

Similar to mine on the Moulton.
Click for better views.

Chainset.jpg
Screen Shot 2019-10-20 at 15.07.31.png
Screen Shot 2019-10-20 at 15.03.49.png
Mick F. Cornwall

philvantwo
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Re: How do I tighten this bottom bracket?

Postby philvantwo » 20 Oct 2019, 3:18pm

What parts will he need to grease Mick F?
:lol: :lol: :lol:
[color=#FF0000][/color]

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asinus
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Re: How do I tighten this bottom bracket?

Postby asinus » 20 Oct 2019, 3:30pm

Thanks, but I don't think it's the same - both crank arms are attached by Allen bolts and the chainwheel is definitely separate from the RH crank.
Asinus

Brucey
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Re: How do I tighten this bottom bracket?

Postby Brucey » 20 Oct 2019, 3:39pm

asinus wrote:
I suspect that it's an oriental imitation of an external BB, of unknown quality - but how do I tighten the chainwheehl on the axle, and the bearings??


A. you don't. You file it under B for 'Bin' and buy something decent instead.

I've not seen one exactly like that before but it looks pretty horrible.

A possible problem is that the torque sensor may be built into the BB, in which case you have to fit the same thing again, or at least something compatible with the rest of the system.

You would think that after ~120-odd years of making ordinary bicycles they would have run out of ways of making them fall apart. Ha. It just takes bolting on an electric motor to one (to power it or make it change gear) and suddenly the market is flooded with rubbish again.

cheers
-------------------------------------------------------------------------------
~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

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asinus
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Re: How do I tighten this bottom bracket?

Postby asinus » 20 Oct 2019, 4:50pm

Thanks - I feared as much.
Asinus

NetworkMan
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Location: South Devon

Re: How do I tighten this bottom bracket?

Postby NetworkMan » 20 Oct 2019, 6:28pm

Is the chainring on splines with a circlip to stop it falling off? If that's the case increasing play is almost guaranteed.

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531colin
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Re: How do I tighten this bottom bracket?

Postby 531colin » 20 Oct 2019, 6:54pm

What do they say where you bought it?


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asinus
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Re: How do I tighten this bottom bracket?

Postby asinus » 20 Oct 2019, 11:26pm

Thanks again all.
Not sure if the place it was bought still exists, they didn't know much about the mechanical side anyway, and we no longer live anywhere near.
The assembly does look a lot like the torque sensor BB on Aliexpress, though I haven't located a wire coming from it, and presumably there isn't any adjustment as with any other cartridge BB.
Asinus

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Gattonero
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Re: How do I tighten this bottom bracket?

Postby Gattonero » 23 Oct 2019, 8:23am

531colin wrote:What do they say where you bought it?


Indeed.
The bike looks fairly new, in those clean conditions you want the bearings to last more than a few months or one year without any play.

Unfortunately, it looks a ill-fated cheap thing, a £25 Shimano square-taper BB unit would tipycally lasts many many years of use, and fairly easy to buy and replace when necessary.
It is by riding a bicycle that you learn the contours of a country best,
since you have to sweat up the hills and coast down them.
Thus you remember them as they actually are...

Polisman
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Re: How do I tighten this bottom bracket?

Postby Polisman » 23 Oct 2019, 8:56am

I've seen this design before also. It was on a supermarket offering which was in all honesty just about the worst bike build I've ever ever come across. At £799.99 they were fairly flying out the store, and everyone commenting on what great value they were.

Unfortunately the bike was almost entirely steel in construction, and I reckon weighed the wrong side of 25kg. It would be a bugger to get onto a bike rack, and probably all advantage lost climbing a hill with assistance due to the lead weight of the thing. Sure enough they were mostly returned to the store under warranty. I can't see how this can work as a retail trade. Maybe its worth it for the few unsuspecting who rarely use their bikes?

Pedelecs at this end of the market seem to be a race to the bottom for low quality parts and build. I recommend spending no less than 1500 for a mix range one. Clearly there's no such thing as a credible 'entry level' electric bike!

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Gattonero
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Re: How do I tighten this bottom bracket?

Postby Gattonero » 24 Oct 2019, 8:05am

Which in turn tells you: what's wrong in spending £500 for an honest, decent bike that you have to pedal yourself? :wink:
It is by riding a bicycle that you learn the contours of a country best,
since you have to sweat up the hills and coast down them.
Thus you remember them as they actually are...

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asinus
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Re: How do I tighten this bottom bracket?

Postby asinus » 24 Oct 2019, 8:37pm

Sadly, this wasn't a £799 job from a supermarket, but a £1700 job from a UK-based specialist - but I think more attention was paid to the electricals than the mechanical parts.

Jamesh
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Re: How do I tighten this bottom bracket?

Postby Jamesh » 24 Oct 2019, 9:51pm

Polisman wrote:I've seen this design before also. It was on a supermarket offering which was in all honesty just about the worst bike build I've ever ever come across. At £799.99 they were fairly flying out the store, and everyone commenting on what great value they were.

Unfortunately the bike was almost entirely steel in construction, and I reckon weighed the wrong side of 25kg. It would be a bugger to get onto a bike rack, and probably all advantage lost climbing a hill with assistance due to the lead weight of the thing. Sure enough they were mostly returned to the store under warranty. I can't see how this can work as a retail trade. Maybe its worth it for the few unsuspecting who rarely use their bikes?

Pedelecs at this end of the market seem to be a race to the bottom for low quality parts and build. I recommend spending no less than 1500 for a mix range one. Clearly there's no such thing as a credible 'entry level' electric bike!



What about a Carrera electric bike from Halfords for £999

Robust and well designed?

Cheers James