|stuck bottom bracket||kyle_4375|
Aug 19, 2001 7:56 PM
|I've gotten my crankarms off the splined bottom bracket and now I can't remove the bb. It won't budge on either side. Any suggestions as to what may be wrong?|
|re: stuck bottom bracket||LC|
Aug 19, 2001 9:45 PM
|You left the BB in too long. If it is a expensive frame you should take it to your LBS, but if you want to take the chance...
Take the bike off the work stand and flip it upside down with the seat and handlebars on the ground. Put a piece of pipe over the end of your wrench to get more leverage. Make sure you know which way to turn the wrench as some frames are reverse treaded.
|re: stuck bottom bracket||alex the engineer|
Aug 20, 2001 3:41 AM
|Are you turning the cups/ends the correct direction? On most bikes, the left one is left-threaded.|
|Mistake warning!||Spoke Wrench|
Aug 21, 2001 5:22 AM
|English threaded bottom brackets, which are the vast majority, have left hand threads on the RIGHT side.|
|sorry||alex the engineer|
Aug 21, 2001 9:11 AM
|had the bike upside down. I generally look at the thread ends, first. I can't keep them straight, so I look at an old set of BB cups BEFORE I turn them the wrong direction.|
|Don't force it - use a bigger hammer.||grzy mnky|
Aug 20, 2001 9:33 AM
|It is possible for corrosion to set in and make things difficult. However, I've never seen a BB that couldn't be taken apart, although I'm sure there are some out there. The trick is having the right tools and sufficient knowldege. Using something like spray on Tri Flow or Liquid Wrench is a good start - try applying some via the top of the seat tube and let everything sit over night. The next thing is to make sure you ahve the right cup tool for your BB. The wrong one or a worn one will make hamburger out of the cups in short order. The next thing is to use a torque wrench for removal. Oftimes poeple think that they are using a "lot of force" when they're really not. This allows you to use a measured and contrlled amount of force to remove the cups. check the mfr.'s spec and set the dial on the wrench. Know which way to turn each cup is critical and there is some variation depending on age of the bike - the newer stuff is fairly standard. Setting the fram up so that it is stable and adequately braced is critical. Having things slip when the applied force is high is a recipe for disaster. If you really feel unsure of the situation or your abilities STOP. It's better to take your time and even take it to a LBS and remove things as designed - I've been amazed at what a willey wrench can do - they see this stuff all the time. Custom machine shop work gets expensive very fast, but usually it's still better than a damaged bike. There should be very little reason to use a "cheater bar" (i.e. a length of pipe) you should be able to generate more than enough force using the proper tools. the cheater bar is really a last resort and the risk of damage is high. |
May the net force be with you.
|Don't force it - use a longer handled wrench||mjc|
Aug 21, 2001 5:03 AM
|the best thing about the torque wrench idea is that it has the cheater bar built into it.|
|Agree, mostly||Spoke Wrench|
Aug 21, 2001 5:46 AM
|First, see my response above.
Second, with stuck bottom brackets, I've had much better luck using Shimano's own tool.
I think that grzy mnky is right when he says prople think they are using a lot more torque than they really are. I think the problem in this case is the commonly used Park BB tool. They stick out too far and are hard to hold square on the shallow Shimano splines. The result is you think you are using enough torque to strip out either the tool or the BB when in fact you are just disengaging the tool and not really doing much.
The Shimano tool engages much closer to the bottom bracket. You have to use some kind of big end wrench to turn it. Unless you have a great big crows foot, you can't use a torque wrench with the Shimano BB tool. Fortunately, I've never had a bottom bracket that I couldn't get out using a Park headset wrench which isn't all that long or particularly robust.
Everytime I say something negative about Park Tools, someone takes me on like I've questioned the existence of God. Park is just another company. They make lots of different tools and I really like most of them. In some cases, however, the Park stuff isn't the best in the business. I think that this is one of them.
|Agree, sort of||grzy mnky|
Aug 21, 2001 8:50 AM
|Yeah, I understand your criticisms on Park Tools - afterall we're not talking Snap-On or Campy! ;-) However, I've found that they're BB tools are great if used correctly - you gotta support the head and keep it on the axis which I'd do with any tool - it's two handed operation and requires a way to keep the frame from moving. Part of the problem of using a headset wrench on the Shimano tool is that by nature, the headest wrenches are really a little too thin for this use - yes they do make them in this size, but they're thin for cranking headsets and pedals with lower applied torque. I find the ability to use a torque wrench on the BB tool far out weighs the shorter cantilever of the Shimano tool. I've never blown the Park BB tool out of the splines using the two handed approach - one handed yes! I have had to slide a QR skewer through a BB to lock the BB tool in place and then turn on the outside once the splines have been damaged. this keeps everything firmly engaged and there's no way it's going to blow out, no matter who makes the BB tool. Ultimately we all work out own techniques and as long as tools and components don't get damaged then they're all valid.|
Aug 21, 2001 10:50 AM
|I'm not too proud of this one but it worked.
I have chucked my Park BB tool vertically in a bench vise and had a co-worker help me thread the whole bike frame onto the splines just like taking off a spin-on freewheel. The BB came off real easy. The hardest part was thinking about which way to twist the bike frame.