BB left to right right to left ??

[razzman]

I used Alex's tutorial to remove the BB from my Specialized Hardrock XC and clean it up etc all running smooth.

Then went onto do the same for my Road Bike, a Giant OCR 4T 2003 with ofmega BB square tapered spline.

Flushed with my previous success I took no pictures and made no notes about how it was already fitted.

The lockring is labeled LH where the BBT engages and RH on the drive side of the BB itself.

However the lock ring and BB seem to only be able to screwed in on opposite sides.

e.g. LH to right-hand side of frame and RH - left hand side of frame.

Do some frames have the BB mounted this way ? and other than potential problems with damaging threads on the frame and BB does this pose any longer term problems?

Thanks

[DaveM]

I'm having trouble following the specifics of your notes. But any bike with English threads (which is all Giants) will have "reverse" threads on the drive side and "normal" threads on the left. Usually the drive side of the BB tightens down to the frame and the lockring goes on the adjusting cup on the left. But not sure if you have anything unusual.

[razzman]

Dave,

Thank you for your reply. Essentially from Alex's tutorial and others I understand that it is the norm for the drive side of the bottom bracket to be threaded into the right-hand side of the frame and the lock ring into the left.

In fact where the park BBT engages with the bottom bracket it does have RH on it (presume to indicate right-hand) and LH on the lock ring. They also have little arrows to indicate the direction that each should be threaded in. However....

Despite I can only get them screwed into the frame on the opposite sides of the frame to the markings on BBT.

e.g. LH to right-hand side of frame and RH to left-hand .
I was aware about the reverse thread and also the rotational arrows on the Bottom bracket parts would have cleared up any confusion.

If I try to mount the bottom bracket the way round that the part indicates and I expect the threads just do not engage at all on either side.

Now of course this it not the usual case. Is this sometimes the case with some frames / bottom brackets?

Also if I am not damaging the threads on either the bottom bracket or the frame does it actually matter?

Thank you.

[cyclerUK]

Normally, as you say, the lockring / adjustable cup are on the none drive side (Left).
This is because you would have trouble getting to the adjustment with chainrings in the way.
Is this a new bike or has someone else owned it previously.
Have a close look at the threads on the cups and see if you determine their direction.

[DaveM]

LH and RH probably refer to left handed and right handed <i>threads</i> rather than to the side of the frame. Right handed threads are "normal" and so go on the left side of the frame. (This is why I prefer the 'normal'/'reverse' naming to RH and LH.)

It doesn't matter which way the BB rotates. But if you try to force the wrong threads in you could seriously damaged the frame.