Bottom bracket threads on 1950s Phillips

[andyz]

I've just started restoring a bike which I rode in the mid to late 70's, and hasn't been used for many years. Its a Phillips frame, but it was built for off-road used, a British Klunker if you like, or tracker as we used to call them.

Anyway, the bottom bracket was a bit rough, so I dismantled it yesterday, and found something rather odd:
The non-drive side cup is the fixed cup, and left-hand threaded.
The drive-side cup is adjustable, and normal threaded.

Is this normal for this period?

Cheers,
Andrew

 

[Midlife]

nope, don't remember anything like that from any era..........the driveside cup is a left hand thread so that it doesn't unscrew in use.

Trying to work out if it's posssible to build it back to front LOL

haun

 

[andyz]

The cups appear to be just like normal ones, its the frame which is weird!
If the drive side is locked and the other side tightens anti-clockwise, how would it undo in use?

 

[Midlife]

Newtons law of motion. Turning the right hand drive side crank clockwise while riding produces an equal and opposite force in an anticlockwise direction. Hence the left hand thread on English bikes on the drive side

never bothered the Italians though lol

Shaun

 

[andyz]

Newtons law of motion. Turning the right hand drive side crank clockwise while riding produces an equal and opposite force in an anticlockwise direction. Hence the left hand thread on English bikes on the drive side

never bothered the Italians though lol

Shaun

Sorry to be pedantic, but its nothing to do with Newton's laws, its called precession. The drive side cup is locked by a lock-ring anyway. In 1000s of miles of use it never came loose either.
Do Italian BBs come loose?

Anyway, still doesn't explain why my BB is threaded like that!

 

[Midlife]

..........well that's blown years of theory Always thought precession was an astronomical / groroscopic term.....

http://sheldonbrown.com/gloss_bo-z.html#bottom

Sheldon Brown thinks that Italian Bottom Brackets have a tendency to unscrew.

Back to the topic, I have no Idea why your BB is threaded like that. I worked in a bike shop in the 70's and came across a lot of quite old bikes but don't remember a reversed bottom bracket. Maybe someone like Keithglos on here who owned a bike shop before that can help.

Shaun

 

[keithglos]

Have you got the chainwheel on the wrong side, ie on the left?

Or its been forced in the wrong sides
Keith

 

[andyz]

Have you got the chainwheel on the wrong side, ie on the left?

Or its been forced in the wrong sides
Keith

No, chainwheel on correct side and threads are perfect.

I'm starting to think that it may have been threaded incorrectly from new! Friday afternoon job, or and incompetent apprentice?

I'll try and find out where the frame came from, but I've a feeling my Dad rescued it from the dump in about 1965! It was ridden for a very long time like that, and I don't remember any issues, but I was only about 10 or 11....

 

[hamster]

Do Italian BBs come loose?

Occasionally yes. I've had one of the little horrors do that and then jam the crank. The reverse threading is for the same reason one pedal has a left hand thread. Precession is effectively the drag from the bearing.

 

[andyz]

I feel the use of loctite may be a good idea!