Replacing my bottom bracket

[mat205125]

I've managed to junk another bottom bracket and want to take on replacing it myself. Working normal office hours, when I can't get too and from the bike shop, plus their normal "will be able to fit it in next month" is just too tiresome.

I've already got a crank remover, and know that I'll need to buy a bottom bracket tool as well, but would appreciate an idea of how tricky this job is to do. Currently got a normal cartridge BB.

What do I need to measure to make sure I order the right size BB in the first place

[BadgerBenji]

Remove cranks, check that it is a square taper, and not isis or some other spline derivative.

Then measure the axle across its bare ends, then measure the width of the bottom bracket shell, thats the piece of frame that the bottom bracket is mounted in.

Assuming you dont have anything odd, its english thread.

Remember one cup is left handed and the other is right handed.

When using the bottom bracket tool, if possible put the crank nut back on to hold the tool in place, it avoids slipping and hurting your bike, you will mend cheaper than a mangled bike

[deevlash]

Its a doddle but as benji said just remember that the threads are right and left specific and make sure you dont cross thread them when youre putting it all back together

[BadgerBenji]

oooh just remembered as well dont forget to put grease on the cups when putting them in, but do not get grease on the bottom bracket axle on the square taper section.

[mat205125]

Cheers guys. Mine is a spline and not a taper.

Will whip off the arms and get out the vernier this evening then.

[BadgerBenji]

Before removing the cranks, you have got the right extractor? There is an extra widget required, which stops the extractor going into the threads.

Same measurements apply.

[mat205125]

Not sure?

Haven't taken these cranks off to date. Will have a check to make sure before getting too carried away.