Odd one - stiff bottom bracket - but only in one direction

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karlt
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Odd one - stiff bottom bracket - but only in one direction

Postby karlt » 18 May 2017, 12:52pm

Son #2's bike - turning the pedals backwards is fine, turning forwards is stiff. It's (in the normal way of putting 40 year old tech on kids' bikes) a cup and cone; I shall probably just stick a cheap cartridge in there. If I can find a box spanner to remove the crank nuts (yes, nuts, it's one of those with a thread on the spindle and nuts holding the crankset to it.

It might just need stripping down, but by the time I've done that and found it is actually knackered it I might as well have the cartridge ready, and if I've got it I might as well fit it rather than fanny around adjusting the thing.

Just thought I'd mention it as a curiosity.

mercalia
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Re: Odd one - stiff bottom bracket - but only in one direction

Postby mercalia » 18 May 2017, 1:29pm

well cycle backwards then :lol:

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NATURAL ANKLING
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Re: Odd one - stiff bottom bracket - but only in one direction

Postby NATURAL ANKLING » 18 May 2017, 2:02pm

Hi,
You don't say what bike / gear set up, check that the chain hasn't something to do with it?
I know it sounds weird, I had a bike which was stiff back pedalling, the chain although was shimano was made in India :?
Links were stiff from new almost.
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karlt
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Re: Odd one - stiff bottom bracket - but only in one direction

Postby karlt » 18 May 2017, 2:10pm

Nah, I unshipped the chain before I started investigating. It's a Raleigh hardtail, front sus only, for the record.

PT1029
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Re: Odd one - stiff bottom bracket - but only in one direction

Postby PT1029 » 18 May 2017, 9:00pm

I have seen this once or twice before. It is when the BB has got corrosion in the bearings (and probably been standing idle for a while), the grease in use results in a bit more grease one side of the balls, and a space the other (due to rotation). The space on one side of the ball gets rust in, which makes it easier to go one way than the other. My description might not be 100%, but dismantling (if possible), cleaning and regreasing should do the trick.
The case I mainly remember was a cheap sealed BB, so in that case it was replaced. I did tell the customer she had been pedalling the wrong way, but she saw through my cheap solution!
I think this problem has been posted in the past, and Brucey had a more competent description that mine if I remember correctly.

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Re: Odd one - stiff bottom bracket - but only in one direction

Postby Vorpal » 18 May 2017, 9:16pm

Some wear patterns on bearing races can do this, too, especially if the bearings have been reused. It may be possible to clean it all & smooth some of the wear with some emery cloth or something like that. It's really only a temporary solution, but likely enough on a kid's bike.
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breakwellmz
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Re: Odd one - stiff bottom bracket - but only in one direction

Postby breakwellmz » 19 May 2017, 6:51am

Had this once, turned out to be a broken bearing cage that would jam the BB axle in one direction only.

Dave W
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Re: Odd one - stiff bottom bracket - but only in one direction

Postby Dave W » 19 May 2017, 6:10pm

I thought I had this last week - turned out one of the cartridge bearings had seized in the Campag freehub.

Brucey
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Re: Odd one - stiff bottom bracket - but only in one direction

Postby Brucey » 20 May 2017, 9:08am

breakwellmz wrote:Had this once, turned out to be a broken bearing cage that would jam the BB axle in one direction only.


this sounds familiar to me. Even if the cage is still in one piece it can still be worn in such a way that the bearing will run in one direction OK but not the other. I think this can happen because the cage is normally driven round by the balls, and over time wears so that it is at least different going one way vs the other.

FWIW If the wear/damage isn't too bad, replacing the caged balls with (more) loose balls is usually an effective cure. If you fit an inexpensive MTB with a decent sealed BB unit, it may (given the 'usual treatment') outlast the rest of the bike, which is both good and bad...

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

karlt
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Re: Odd one - stiff bottom bracket - but only in one direction

Postby karlt » 21 May 2017, 8:55am

Breakwellnz wins. One bearing cage utterly mangled.

MikeF
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Re: Odd one - stiff bottom bracket - but only in one direction

Postby MikeF » 21 May 2017, 9:21am

karlt wrote:Breakwellnz wins. One bearing cage utterly mangled.
Replace with non caged bearings perhaps?
"It takes a genius to spot the obvious" - my old physics master

karlt
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Re: Odd one - stiff bottom bracket - but only in one direction

Postby karlt » 21 May 2017, 1:41pm

Could have. Just banged a sealed cartridge in.

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meic
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Re: Odd one - stiff bottom bracket - but only in one direction

Postby meic » 21 May 2017, 1:44pm

A solution that I arrived at years ago!
I have a drawer with plenty of perfectly good cup and cone bottom brackets in, all have been replaced with fit and (almost) forget sealed units.
Yma o Hyd

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NATURAL ANKLING
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Re: Odd one - stiff bottom bracket - but only in one direction

Postby NATURAL ANKLING » 22 May 2017, 9:33am

Hi,
I save all sealed BB's from the skip bikes I break up to reuse on another project, as said the sealed variety which come out in one piece will out last the rest of a cheap bike.
Most of the cheap mtb;s sold by Halfords etc tend to have loose BB's I find.
A number of sealed loose ball bb's but they are normally of cheap manufacture so the bearings tend to go oval with little use by me :)
Even if sealed one piece bb's a little rough when turned by fingers, if no play exists then they are serviceable for reuse.
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You'll Still Find Me At The Top Of A Hill
Please forgive the poor Grammar I blame it on my mobile and phat thinkers.