Bicycle Mechanics - Bottom Braket Lockring/Cup

Bikeforums.net is a forum about nothing but bikes. Our community can help you find information about hard-to-find and localized information like bicycle tours, specialties like where in your area to have your recumbent bike serviced, or what are the best bicycle tires and seats for the activities you use your bike for.




View Full Version : Bottom Braket Lockring/Cup


jelucier
07-11-10, 10:54 AM
Hi,

I'm having difficulty removing the left side cup and lockring on my mid 80's stumpjumper. It won't move when I wrench it. I used penetrating oil, but it is stuck. What should I do to get it to loosen up and remove it?

Jeff


JohnDThompson
07-11-10, 11:51 AM
What have you tried at this point? You should use a hooked spanner to remove the lockring, like the upper tool in this picture:
http://www.os2.dhs.org/~john/atd-bb.jpg

Once the lockring is off, you can use a pin spanner to remove the cup:
http://www.os2.dhs.org/~john/atd-pin.jpg

Bike shops often have more effective (and expensive) tools they can bring to bear if you can't do the job with the tools you have at home.

2_i
07-11-10, 12:45 PM
Single hook is most often insufficient, i.e. sufficient for destroying the lockring but insufficient for moving it. Few grab points are preferred. Otherwise, to remove the cup, you need secure the BB tool with a bolt+washer screwed into the axle of BB, to keep the tool in place.


FBinNY
07-11-10, 12:59 PM
Sometimes it takes more than gentle force to pop off an old lockring. This is the tool (http://www.sheldonbrown.com/var/pages/var0013.html) of choice used by old timers who do lots of these. If you don't want to buy or borrow one, consider letting the LBS do this job, or simply set an old dull chisel into one of the notches and giving it a sharp hammer blow. Don't tap it, that just drives the chisel in, give it a meaningful shot which should sent it spinning off.

Once the lock ring is off you can try the cup, but if it's rusted in there's a good chance that it'll shear the pins off a two pin tool. There were 6-pin tools back in the day for stubborn cups, but i don't know if they can be had today. If 2-pins isn't enough, and you have a small home shop, you can make a 6-pin tool yourself from scrap metal, or resort to desperate measures. Try driving the cup out with a chisel or punch set into a hole, or try grabbing the cup with a big pair of Channellocks, or try clamping the cup in a vise and turning the frame.

If it's really seized, you might try getting the right side off first (Don't forget that many are left hand threaded) then using a fine thread 9/16" bole and nut to work the left off.

garage sale GT
07-12-10, 04:36 AM
If I am not reusing a lockring I remove it with a pipe wrench. Make sure you are turning the right way.

jelucier
07-12-10, 09:15 AM
Ok, thanks for the great advice. I actually ordered the park tools necessary for the job.

Now the stupid question, which way do I turn it off? Right or left?

Jeff

FBinNY
07-12-10, 09:20 AM
Ok, ....

Now the stupid question, which way do I turn it off? Right or left?

Jeff

That's easy, left is always right. It's right that's tricky; left for British, and right for French and Italian.

To clarify, It's a RH thread so you turn it counter-clockwise to loosen.

JohnDThompson
07-12-10, 10:35 AM
Ok, thanks for the great advice. I actually ordered the park tools necessary for the job.

Now the stupid question, which way do I turn it off? Right or left?

Jeff
Adjustable cups are always standard thread, so counterclockwise will loosen it.