Screw you bottom bracket

[Milkfloat]

I think you need to edit the thread title to 'Unscrew you bottom bracket'.

 

[Yellow Saddle]

My BB is also seized on the non-drive side. I've used the official Shimano tool but no joy.

The other side came out easily but this side - no joy. All I did was scuff the "thread". I was thinking about brute force but have stayed away from this so far. Maybe I need to have another go! I don't mind destroying it as I have a new one to replace it.

You need the BB socket. It covers all the splines and so to their complete depth. Many brand are available including Shimano and ParkTool. Choose one that has the right ratchet drive size - 3/8th or 1/2".

 

[GrumpyGregry]

Even with right tool steel tool alloy cups is an unfair fight if the cup is seized.

 

[Buck]

You need the BB socket. It covers all the splines and so to their complete depth. Many brand are available including Shimano and ParkTool. Choose one that has the right ratchet drive size - 3/8th or 1/2".

Yes. I have the Shimano one.

Even with right tool steel tool alloy cups is an unfair fight if the cup is seized.

And I think this is my challenge as the seized unit is still winning even with the "official" tool.

 

[Tim Hall]

You need the BB socket. It covers all the splines and so to their complete depth. Many brand are available including Shimano and ParkTool. Choose one that has the right ratchet drive size - 3/8th or 1/2".

Yes. I have the Shimano one.

Even with right tool steel tool alloy cups is an unfair fight if the cup is seized.

And I think this is my challenge as the seized unit is still winning even with the "official" tool.

<possible egg sucking lesson>What I've done it the past is secure the BB tool to the BB using a crank bolt and suitably large washer. Get it nice and snug. Then put the socket (32mm in my case), 10 inch bar on it and then a handy length of scaffold tube a couple of feet long.
<end of lesson>

 

[Arjimlad]

I have found it easier to put the tool in my engineer's vice, then drop the BB onto it.

Pushing down with one hand to hold the BB on the tool I then rotate the frame for leverage.

 

[keithmac]

I have to contend with seized fasteners and bolts on a daily basis at work, all for the want of a bit of anti seize paste on first assembly..

Shallow headed allen bolts with threadlock from hell are another joy.

 

[rogerzilla]

I once broke the splines off a Shimano BB tool and still didn't get the BB out. The LBS did it in the end.

 

[mjr]

I have to contend with seized fasteners and bolts on a daily basis at work, all for the want of a bit of anti seize paste on first assembly..

Shallow headed allen bolts with threadlock from hell are another joy.

I just met one of those while replacing a broken mudguard.

I'm rereading this thread because I also failed to get the BB out of that bike. It's OK for now but is feeling worn. I really hope they didn't threadlock the BB...

 

[si_c]

I really hope they didn't threadlock the BB...

I don't really understand the point of threadlock on a BB given they self tighten.
Just fitted a new one a week ago, removed the threadlock prior to fitting and added lots of grease to the threads. Do this every time now.

 

[mjr]

I don't really understand the point of threadlock on a BB given they self tighten.

Do they? It seems to me like the circulating forces should undo a loose square-taper cartridge BB if anything, but maybe I'm not thinking clearly. I hate physics.

I'd also remove the threadlock, grease it and torque it to about 440in lb = about 5.1 kg m unless otherwise indicated.

But I didn't fit this one, I think it was fitted by someone who didn't grease another now-replaced part and I suspect it's good old metal cup corrosion

 

[Tim Hall]

Do they? It seems to me like the circulating forces should undo a loose square-taper cartridge BB if anything, but maybe I'm not thinking clearly. I hate physics.

No, precession is your friend, combined with a left hand thread on the relevant* side makes the circulating force tend to tighten them. This applies to "British" threaded bottom brackets. Italian threaded bottom brackets have both sides right hand threaded, so have to be done up bastard tight.

The nett effect of British threaded and Italian threaded systems is that they're hard to undo, but for different reasons.



*Note how I didn't specify left or right side. That's because I can't remember.

 

[si_c]

No, precession is your friend, combined with a left hand thread on the relevant* side makes the circulating force tend to tighten them. This applies to "British" threaded bottom brackets. Italian threaded bottom brackets have both sides right hand threaded, so have to be done up bastard tight.

The nett effect of British threaded and Italian threaded systems is that they're hard to undo, but for different reasons.



*Note how I didn't specify left or right side. That's because I can't remember.

If it's not ISO it's a pain. The right hand (fixed) cup is the one which needs to be opposite threaded.

 

[Venod]

so have to be done up bastard tight

My favourite torque setting.

 

[Lonestar]

I don't really understand the point of threadlock on a BB given they self tighten.
Just fitted a new one a week ago, removed the threadlock prior to fitting and added lots of grease to the threads. Do this every time now.

Mine kept coming loose so,so much for the self tightening.Used a tiny bit of threadlock but it was still a bitch to get off.