Fitting a Sealed BB

[madmaxusm]

Just wondered if fitting a sealed BB was the same as fitting a loose bearing one.

When tightening the screws on the sealed BB do you do just the same as on a loose bearing model ie. Tighten up until you loose all play in the bearings but not too much that the crank won't trun freely.

Any help much appreciated.

[pickle]

i'm no expert on these things but i think it might be diferent depending on crank and BB??

what crank and BB is it?  piccies will help too 

[madmaxusm]

This is the crank and sealed BB :

[pickle]

i've never fitted one of these before....but do they not require a spacer in the middle so you don't crush the barings?

[Rooonga]

Yeh looks similar to the profile bb set. Will need a spacer between the bearings.

I used a small bit of 22mm copper tubing cut down to size on a set that didn't come with the spacer. Nice fit, and keeps the bearings spinning properly.

[madmaxusm]

Hi

Found this pics and the kit does not come with a spacer by the look of things...how long should the spacer be ?

[TwoBobRob]

Two ways to do this.

The 'right' way is to have a spacer fitted between the bearings as the other lads have said, then do everything up nice and tight.   However, lots of riders used to do away with that spacer and just nip everything together on the tight side so that your cranks didn't rotate and disappear when you did no-footers.  Important to threadlock the bolts if you do this though  

I did this on my Condor for years and it had no real bad effect on the bearings, mine lasted 5-6 years or so  


You can buy the spacer individually I think, or people will have spares on here but beware, there are two different sizes based on the width of your BB  shell. One is metric and one is imperial....

[perry]

theres a simple way to determine the width of the spacer to use

and id use a spacer otherwise the bearings have an unessesary load on them and increased friction  ( mightas well ride with the brake on )

take the 2 bearings and offer them up to the underside of the bottombracket shell , im guessing theres a lip to the cups the bearings sit in to stop them dissapearing when being fitted so that makes it even easier

the size needed is the gap between bearings 

cut a bit of tubing if needed ( im sure plenty of people have spares kicking about you could have ) and just file for a precise fit 

[sonic-1]

the ct crank set dont come with a spacer yer fit it so the treded collers on the crank sit in bearings without puting side load on them then yer use the lock nut to stop it coming undone !!!! takes a couple of goes to get it just right as when yer do the lock nut it tightens it a little
then they run smooth as silk

[madmaxusm]

Cheers all !!!

Many thanks for all your help 

I will try without the spacer to start and see how it goes, if I am not happy I will make a spacer and try that.

[madmaxusm]

Just one more quick question

Will this fit a 92 Robinson SST frame ok.

Many thanks in advance

[SaMAlex]

the ct crank set dont come with a spacer

Like the man said, those cranks dont use a spacer, they are designed to not need one. You lock the BB nuts up independantly of the crank arms, where as on Profiles, the arms also tighten up the BB so you just crank (haha) them up tight, hence needing the spacer

[madmaxusm]

Thanks for the info, the only reason I asked about if the BB would fit the Robinson frame is that when I fiitted the cups earlier they seemed to go in very easy (like they were slightly too small).

Are there different sizes of BB cups or are they designed to fit all frames ?

[Gary72]

I have Robinson pro and found that my OPC shells fell in, so dont know if it is a Robby thing, I'm looking to use 3 piece and if they are loose might go with the tin can shim method

[SaMAlex]

There is/was only one size of USA BB, but there is no set standard for what the size is! It was a right nightmare, esp if you were trying to make a frame. If you got 10 brand new BB cups from different cranks they would all be slightly different sizes! If you make the frame BB large enough for the biggest cups, the smaller ones would be too loose! Same applies if you were trying to make BB cups.

Mid Vs Spanish is hard to pick ... but a BB size that actually has a set size to it is great!

[madmaxusm]

Again thanks for the info guys !!!

I will get it built up and see how things go, only one way to find out i guess