Modern BBs are rubbish

[derrick]

Took the BB out of my wife's Cervelo R3 today, The bearing are so small they are not really up to the job, Have seen bigger bearings in a sewing machine, Did want to do a conversion on it but have found a set of ceramic bearings so will give them ago, Have ordered them but they will not be here for a couple of days, I can't believe
the original bearings are fitted to a plastic housing, Talk about cheap and cheerful, did not expect to find that on an expensive bike. PF30. The job itself is a piece of cake so no problems there. Just got to wait a couple of days before i can refit it.

 

[Yellow Saddle]

Don't expect the ceramic bearings to be any better. If your previous ones failed due to load problems rather than lube failure, the ceramic ones will fail even quicker.

 

[Katherine]

Mine seized up on my 4 month old Dawes Super Galaxy! I had to be rescued 16 miles from home. The shop replaced it the next day.

 

[derrick]

Don't expect the ceramic bearings to be any better. If your previous ones failed due to load problems rather than lube failure, the ceramic ones will fail even quicker.

The bearings have not failed, it's the bearing housing is made of some kind of plastic, over time the plastic flexes causing the creak, but at the end of the day the bearings are not up to the job.
It is the PF30 BB just rubish.

 

[fossyant]

Get a praxis works converter and go back to hollow tech or ultra torque.

 

[Yellow Saddle]

The bearings have not failed, it's the bearing housing is made of some kind of plastic, over time the plastic flexes causing the creak, but at the end of the day the bearings are not up to the job.
It is the PF30 BB just rubish.

I agree it is rubbish, but like I say, don't expect the ceramic bearing unit will last longer. There is an inherent design flaw in left hand BB bearings and no matter what the actual ball bearing cartridge is made of, it will fail quickly. The so-called ceramic bearings are actually hybrid bearings with ceramic balls and steel races. Although the ceramic ball is harder than steel, that is what causes the problem in this hybrid combination. The steel race actually fails far quicker than its cheaper steel-on-steel cousin.

 

[User6179]

The bearings have not failed, it's the bearing housing is made of some kind of plastic, over time the plastic flexes causing the creak, but at the end of the day the bearings are not up to the job.
It is the PF30 BB just rubish.

The plastic housing is there to cure the problems that you get on standard BB30s with clicking , same as Shimano PF which I found to be the most reliable BB I have used .
Never used the PF30 but looks much the same as the Shimano .

 

[Yellow Saddle]

The plastic housing is there to cure the problems that you get on standard BB30s with clicking , same as Shimano PF which I found to be the most reliable BB I have used .
Never used the PF30 but looks much the same as the Shimano .

No, the plastic housing is not there to cure clicking. It comes with its own built-in clicks. The plastic housing is to cope with the inaccuracies of a carbon BB shell. Proper BB30 can only be done on a metal BB shell that can be machined to good tolerances.

 

[derrick]

Get a praxis works converter and go back to hollow tech or ultra torque.

Have a mate who had a Praxis fitted, 6 months down the line it's creaking, Don't think there is an answer to it. We will carry on suffering the dreaded creak.

 

[derrick]

No, the plastic housing is not there to cure clicking. It comes with its own built-in clicks. The plastic housing is to cope with the inaccuracies of a carbon BB shell. Proper BB30 can only be done on a metal BB shell that can be machined to good tolerances.

You beat me to it. It's a cheap way of putting in BB30s.

 

[lpretro1]

Fully agree with Yellow Saddle - it is not the bearings per se - it is the bike manufacturers who do not adhere to what are quite strict machining tolerances for these items to work properly.

 

[User6179]

No, the plastic housing is not there to cure clicking. It comes with its own built-in clicks. The plastic housing is to cope with the inaccuracies of a carbon BB shell. Proper BB30 can only be done on a metal BB shell that can be machined to good tolerances.

I disagree, well I think we are both correct as my carbon bike and a lot of carbon bikes have a metal insert inside the BB so its not there because of the carbon shell plus the PF is now fitted in some Ally bikes with no carbon .

 

[derrick]

I agree it is rubbish, but like I say, don't expect the ceramic bearing unit will last longer. There is an inherent design flaw in left hand BB bearings and no matter what the actual ball bearing cartridge is made of, it will fail quickly. The so-called ceramic bearings are actually hybrid bearings with ceramic balls and steel races. Although the ceramic ball is harder than steel, that is what causes the problem in this hybrid combination. The steel race actually fails far quicker than its cheaper steel-on-steel cousin.

I know you are spot on, But the Ceramic bearing come in an alloy housing, Am hoping fitted with loctite 609 it may last a bit longer.

 

[derrick]

I disagree, well I think we are both correct as my carbon bike and a lot of carbon bikes have a metal insert inside the BB so its not there because of the carbon shell plus the PF is now fitted in some Ally bikes with no carbon .

It's fitted as a cheap option,

 

[User6179]

I know you are spot on, But the Ceramic bearing come in an alloy housing, Am hoping fitted with loctite 609 it may last a bit longer.

Will you not still need the plastic bit to put the ceramics bearings in ?