BB replacement advice

[ohnovino]

The grinding from my bottom bracket is now loud enough to scare the local wildlife, so I've decided to have a go at replacing it. It's a Shimano cartridge type, and I've had a look on various websites so I think I know what I'm doing, but I'd appreciate it if some experts could glance over my checklist and tell me where I'm going wrong:

• Remove crank arms
  Remove the crank bolts with a hex key. Screw in the crank extractor so it's tightish. Then tighten the inside bit until the arm comes off.
• Remove the cartridge
  Align the bottom bracket tool, then use a big spanner to undo the screw threads on each side (non-drive side first??)
• Clean everything
• Fit replacement cartridge
  Grease up the threads, then screw it into place (again, non-drive side first??)
• Refit crank arms
  (Is this just a case of screwing in the crank bolts?)
• Ride away and hope nothing falls off

Any help/advice/warnings would be very greatly appreciated

 

[ismailzd]

The grinding from my bottom bracket is now loud enough to scare the local wildlife, so I've decided to have a go at replacing it. It's a Shimano cartridge type, and I've had a look on various websites so I think I know what I'm doing, but I'd appreciate it if some experts could glance over my checklist and tell me where I'm going wrong:

• Remove crank arms
  Remove the crank bolts with a hex key. Screw in the crank extractor so it's tightish. Then tighten the inside bit until the arm comes off.
• Remove the cartridge
  Align the bottom bracket tool, then use a big spanner to undo the screw threads on each side (non-drive side first??)
• Clean everything
• Fit replacement cartridge
  Grease up the threads, then screw it into place (again, non-drive side first??)
• Refit crank arms
  (Is this just a case of screwing in the crank bolts?)
• Ride away and hope nothing falls off

Any help/advice/warnings would be very greatly appreciated

1. Make sure you don't tighten it too much otherwise it will damage the arms.
2. removing the BB is the hardest thing, start with the left side, the right side is much harder.
Follow the same procedure and you will be fine.
:

 

[Alien8]

Assuming it's a regular ISO/English BB remember the thread direction - drive side is left-handed, non-drive side right-handed. If the adjustable cup is plastic remove the fixed drive side first. Install the fixed drive side first. Take your time to avoid cross-threading it - you should be able to install each side a fair way by hand. If it seems to be binding either the threads aren't clean enough or you're cross threading it. TAKE YOUR TIME.

 

[battered]

Yes indeed, take your time, and ensure the threads are VERY clean before starting. A wire brush is good. Best practice is to ensure it will screw in, get everything clean and dust free, then put on a LIGHT smear of coppergrease or other antisieze compound.

 

[ohnovino]

Thanks for the tips guys - I've ordered the necessary bits and bobs, so I should be able to give it a go at the weekend.

 

[swee'pea99]

It's been said - by Alien8 - but forgive me for reiterating the point about the odd threads. The left hand end (as you sit on the bike) screws off 'normally' - like you're removing the lid from a jam jar. To remove the other end (the drive end) you have to screw the other way. Clockwise. Sorry if I'm being OTT, but it's quite important that bit!

 

[ohnovino]

Job done! I now have a BB that's beautifully smooth and completely silent, so now I can scalp people without them hearing me coming! It's good to know I'd diagnosed the fault properly, but it's also made me a little embarrassed at how bad I'd let it get

Thanks again everyone for the advice. I took it slowly, and had a piece of paper stuck to my toolbox reminding me which way the threads go.

 

[Alien8]

Nice one - jobs a good'un!

 

[cyberknight]

Good job , when i did mine the bike was leaning at on a wall so i kept cross threading the plastic non -drive side .