Modern BBs are rubbish

[zacklaws]

Now along comes Johnny and opens his BB to replace the bearing inside. He takes the plastic cup off and sees inside that it is an 6805 RS/2 bearing. Bingo! he thinks and goes to the bearing shop and buys two 6805 RS/2 bearings. He fits them and finds that they are 1mm too thick (wide). He double-checks the code and sees that he did not make a mistake, he used the right code. He then measures the old bearing which is marked as 6905 and sees that it is only 6mm wide. Puzzled, he gives up.

Yes, I'm puzzeld now, Johnny see's he has a 6805 RS/2 bearings in his BB and orders those, but they do not fit correctly, so he checks again to see if he had made a mistake and he had not, but when he checks his old bearing, it is now marked as 6905?

I think Johnny would be better off going to specsavers so that he can read the codes on the bearing correctly the first time.

 

[Yellow Saddle]

Yes, I'm puzzeld now, Johnny see's he has a 6805 RS/2 bearings in his BB and orders those, but they do not fit correctly, so he checks again to see if he had made a mistake and he had not, but when he checks his old bearing, it is now marked as 6905?

I think Johnny would be better off going to specsavers so that he can read the codes on the bearing correctly the first time.

Nope, Johnny's eyes are good. 6905 bearings are 9mm wide with an ID of 25mm. Different bearing, different BB. Nevermind....

 

[derrick]

I have fitted one of these, http://www.madison.co.uk/products/c...essfit-30-bottom-bracket-ceramic-bearing-red/
See how long this last's.

 

[Yellow Saddle]

I have fitted one of these, http://www.madison.co.uk/products/c...essfit-30-bottom-bracket-ceramic-bearing-red/
See how long this last's.

Good luck. Let us know how it holds up.

 

[zacklaws]

He then measures the old bearing which is marked as 6905 and sees that it is only 6mm wide.

Nope, Johnny's eyes are good. 6905 bearings are 9mm wide with an ID of 25mm

Somebody needs to go to specsavers then, is a 6905, 6mm wide or 9mm wide, no wonder their is so much confusion with BB bearings if they change size every hour or two.

 

[GuyBoden]

After reading the title of this thread and the thread posts, I'm about to change the BB on a used road bike I purchased recently, I've removed the BB, it's a standard 68x110mm square taper English thread type.

So, do you think it is a good idea to convert to an old style spindle, bearing cups and loose bearing type?

 

[zacklaws]

I would love to go back to something like that on my "Work Horse" that clocks the miles up, at least when you get play you can tighten the cones up and also you can strip it all down and clean it. In fact I cannot ever recall wearing a BB out in them days and replacing everything, the only thing ever done was adjust them for play. I have just got rid of an old Raleigh, 30+ years and it still had the original BB in.

 

[Tim Hall]

After reading the title of this thread and the thread posts, I'm about to change the BB on a used road bike I purchased recently, I've removed the BB, it's a standard 68x110mm square taper English thread type.

So, do you think it is a good idea to convert to an old style spindle, bearing cups and loose bearing type?

Yes. Put a Shimano UN55 in there. The subject of the original discussion was one of those new fangled fancy pants external bearing jobs. Mind you your one does lok very shiny, so if it's not giving you any grief AND you can adjust just right, you could leave it in.