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Crunchy sounding bb...
 

[Closed] Crunchy sounding bb. What are the options?

Posts: 8328
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Got myself a 2020 defy, done about 800 mainly dry miles and the bb is crunching badly when putting out high torque/low cadence efforts.

Called the bike shop but they are completely full until mid July!! I don't have any press fit bb tools, nor know anything about pressfit bb maintenance. The chap mentioned bearings may just need a decrease. Can this be done with the bb still in situ? I assumed the unit was sealed so this would not be possible.

Ta


 
Posted : 09/06/2020 1:26 pm
Posts: 7617
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Pop the cranks off and have a look.

If you can see the bearings then just carefully take the seals of and clean and re-grease the bearings.

If the balls are badly pitted it wont make a huge difference, but if its just dirty you should be able to eke out some more miles.

Or you could just buy the right tools and change the BB. its not a hard job, its pretty much the same as fitting / removing a headset but you do need the right tools.

Would be a lot quicker than waiting until July


 
Posted : 09/06/2020 1:56 pm
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My Giant Anthem came with the chainset bearing preload torqued up too much so removing / checking and reattaching might be a good first step.

I've been lucky with press fit, I'm still on the original XT BB after 1500 miles and still as smooth as butter / no creaks. However, it isn't uncommon for them to go early on if they've been fitted poorly. Wheels Manufacturing / Hope do some excellent solutions that will sort out many potential problems when its time to replace.


 
Posted : 10/06/2020 11:44 am
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Buy the pressfit tools or learn how to use a hammer, you are going to need them, as you say the bearings don't really last that long.

In the meantime pop the seals, clean and grease to put them on a bit.


 
Posted : 10/06/2020 12:29 pm
Posts: 3783
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Sometimes just removing the cranks and cleaning everything is enough without removing the bb bearing seals.

You can tell when you rotate them if they are OK or not.


 
Posted : 10/06/2020 12:34 pm