Removing bottom bracket

[Zippy]

I am planning to remove the bottom bracket cassette as I will be hacksawing a fused seat stem out of the downtube and don't want aluminium filings in my BB!

Is this a straight forward op? Anything to look out for?

There again the BB cassette is about six years old (though with no problems) so maybe it is time to have this replaced at the same time?

 

[alecstilleyedye]

bottom bracket tool and crank puller, with big adjustable spanner. a five minute job with the right tools, a bike shop job if you don't have them. you'll need the same to replace the bb once you've finished, or to put in a new one.

 

[Zippy]

thanks, and are BB cassettes universal or are there some things to look out for? If its a 5 min-ish job I may as well replace it myself.

 

[MichaelM]

If it's a cassette BB, then it's sealed an it doesnt matter wherther or not some swarf falls on it.

Check size of BB, shell and length, also, not all square taper cranks fit all square BB.

 

[Zippy]

OK thanks. I know it is a cassette, so I guess for the seat stem op that is ok.

When it comes to replacing the BB, I'll take the part to my lbs to be sure.

... and yes, i'll be loosening and resnugging my BB to make sure it is not seized as well, along with my headset! This is a hard lesson to learn, but one never forgotten.

 

[accountantpete]

BB's can be a complete barsteward like seatposts!

If you are replacing it take a look at the externally mounted BB's - they are a big improvement IMHO.

 

[HelenD123]

BB's can be a complete barsteward like seatposts!

If you are replacing it take a look at the externally mounted BB's - they are a big improvement IMHO.

Yes, I was told the Hollowtech BBs were a similar price to the old sort and they are much easier to install and remove. No special tool required.

 

[Rhythm Thief]

They're easy enough to remove, if you think about it a bit. The best way is to clamp the removal tool to the bottom bracket with a bolt and a large washer in the crank bolt hole. This prevents it slipping off while you wield the spanner. Either that, or clamp the tool in a vice and use the bike frame for leverage. Oh, and bear in mind that one side (can't remember which) is a left hand thread, so will undo the other way.

 

[Zippy]

Can anyone post me a link to an external fitting BB cassette? I can't quite get my head around how it fits and what it looks like.

 

[BigSteev]

I am planning to remove the bottom bracket cassette as I will be hacksawing a fused seat stem out of the downtube and don't want aluminium filings in my BB!

The seat stem is stuck in your downtube?!! I think I see a problem here.
Assuming you actually meant it's stuck in the seat post tube I'd imagine that having the frame upside down when doing any hacksawing would stop filing encroaching on your BB.
As for BB replacement, things to remember are is it British or Italian threaded, Shell width (68 or 73mm normally) and then is it the correct taper for the cranks if they are the square taper sort. Of course if they're ISIS or Octolink or Ultra-Torque or.......etc. Simplest is to remove the old one, take it along to the LBS, and get one the same.

 

[HelenD123]

Can anyone post me a link to an external fitting BB cassette? I can't quite get my head around how it fits and what it looks like.

Something like this

or this

 

[SimonC]

Bear in mind that your current chainset will be no good for an external bearing BB.

 

[SimonC]

Axle is part of cranks on external bearing BB's, larger diameter and hollow for strength/weight, so bearings have to be bigger so wont fit in a standard bb shell, therefore fitted external to shell.

Thats why they are cheap compared to cartridge bb's - no axle, just bearings and cups.

Also, I bet that bb cartridge thats been in for 6 years will be a right pig to remove. I would be tempted to leave well alone if its still OK, and doesnt come out easily. Nowt to be gained by taking it out, you cant regrease it anyway.

 

[swee'pea99]

You say you know it's a cassette - so leave it alone! You can't get filings in it; it's sealed. Good luck with the stem - they really are buggers!