Removing BB then fitting new BB

Chucker_Dude

Could anyone please tell me how to remove a bottom cracket? And then fit a new one? And also what tools i will need for each job.

Any help is appreciated

Scubar

Read this and it should give you all the info you need about replacing a bottom bracket, Its very simple and only takes a few minutes to acheive with the correct tools.

http://www.parktool.com/repair/byregion ... Field2.y=2

MarvintheAndroid

If you don't already have the tools, and depending which sort of BB you have, it may be cheaper to get your LBS to do it than buying everything from scratch. Just a thought.

Marv

Chucker_Dude

Thanks, but that information is a bit confusing

i dont understand some of it :oops:

And as i work at my LBS, i have all the tools at hand

MarvintheAndroid

If you work at your LBS, where is the problem ? Surely someone in the building should know this stuff, even if you don't. I am resisting the urge to think you are taking the p*ss, such is my trusting nature....

OK, begin with what sort of bottom bracket do you have - is it square taper axle, hollowtech, hollowtech II with pinch bolts on the left crank, ISIS or whatever. If you have difficulty describing it, send a photo.

Are you planning to replace with the same type, or upgrade to something different ?

Marv

Chucker_Dude

MarvintheAndroid wrote:

If you work at your LBS, where is the problem ? Surely someone in the building should know this stuff, even if you don't. I am resisting the urge to think you are taking the p*ss, such is my trusting nature....

OK, begin with what sort of bottom bracket do you have - is it square taper axle, hollowtech, hollowtech II with pinch bolts on the left crank, ISIS or whatever. If you have difficulty describing it, send a photo.

Are you planning to replace with the same type, or upgrade to something different ?

Marv

First, im not taking the p*$s. We are not allowed to work on our own bikes during our own working hours. I have to go into my LBS during my free time. If anyone helps me, me and the person who helped me may get in a bit of trouble with the boss, as hes strict on stuff like this.

Its a square taper axle. I'm going to fit a Shimamo BB, although im not sure what the exact model is.

The new bracket looks like this...

http://www.evanscycles.com/large_images/F626_BIG.jpg

MarvintheAndroid

OK. You need a square taper crank removal tool and a shimano splined bottom bracket tool - hopefully your shop will have a decent professional one with plenty of leverage and not the poor pathetic things we mortals have to use.

The bit of Park Tools you need is here http://www.parktool.com/repair/readhowto.asp?id=94

Begin by removing the cranks, then remove the cup on the non-chainring side. This is a normal direction thread. It will be tight but shouldn't be too bad.

When this is removed, depending on the type you have either the axle and bearings will fall out, or the bottom bracket cartridge will still be in place but will be free at one end. It makes no difference to the method.

Now use the same tool to remove the bottom bracket from the chainring side, this will be VERY tight and you will probably have to clamp the tool on to the BB. This is a reverse thread direction.

When it is out, clean and inspect the threads for damage and use a little copaslip or grease in the threads before re-fitting.

Now fit the new cartridge assembly in the reverse sequence, screw the new bottom bracket in from the chainring side (reverse thread) until it is very tight, then fit the non-chainring side cup (standard thread).

Check that the axle rotates freely and install the cranks.

Marv.

Chucker_Dude

Woah thats really helpful! i'll print it off and follow that when i do it this week

thanks alot marv!

MarvintheAndroid

It's one of those jobs where you can end up skinning your knuckles, so go careful. If you don't have a sturdy bike stand or vice, a second pair of hands will come in - well - handy.

Marv

Chucker_Dude

hmm...i dont know whether to do it myself (sounds a bit tough) or just leave it with the guys at the LBS :?

Scubar

Its extremely easy providing you have the correct tools.