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Stumpjumper BB install


Carbon_Kooi
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Hi all,

 

A friend bought a 2009 Specialized Stumpjumper S-Works, and asked me to do the build for him.

I am a bit confused/uninformed of how to install the specific press fit BB that came with this frame. It is the BB 91-42. I have seen a lot of videos on the press fit BB installation but none of them are the same as this BB. Most of the have the little lip that presses against the BB shell when fully pressed in or the frame takes a clip that stops the bearing when fully pressed in, this one has nothing like this?

 

Any help?

Edited by Carbon_Kooi
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Take a piece of 10mm rod and find 4 washers with a larger outer diameter that the BB shell.

 

Put the rod through the BB and put 2 washers on each side.

 

Now put a not on each end of the rod. Tighten from both ends to get equal force on both side..

 

The washers will press the BB into place and because the washers are bigger than the BB, it wont press into the shell but sit flush with it.

 

Maybe try to put some copper paste on the BB before inserting it - should make fitment easier.

 

I did mine like that at the office - but it did have a lip.

 

Enjoy!

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Thanks for the replies.

AndreZA this one does not have the lips, it is a specialized one for Specialized :)

Maybe I will take it to the LBS to have a look....

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Did you take the C clips out of the bb shell? you need to take these out and then put the presfit bb in. You are going to need the correct BB tool if you are to do this correctly.

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There are no circlips in the shell, so my question is how deep do I press these into the shell, until they are flush? At the moment they are about 3mm from flush.

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There are no circlips in the shell, so my question is how deep do I press these into the shell, until they are flush? At the moment they are about 3mm from flush.

 

It should be flush agains the bb shell. I think you will struggle if you dont have the tool to pull the bb in with.

you risk damaging the bb and the shell by hitting it in

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I went to the bike shop ad they confirmed it is correct. Here is a pic.

sorry the BB phones seem to have the worst cameras ever ;)

post-7170-0-83294100-1320302690.jpg

Edited by Carbon_Kooi
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Cut cut cut cut cut

 

Tighten from both ends to get equal force on both side..

cut cut cut

 

 

Methinks if you just tighten it from one side you'll have the same effect.

 

Newton said: "The anchor pulls as hard on the ship as the ship pulls on the anchor."

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Hi all,

 

A friend bought a 2009 Specialized Stumpjumper S-Works, and asked me to do the build for him.

I am a bit confused/uninformed of how to install the specific press fit BB that came with this frame. It is the BB 91-42. I have seen a lot of videos on the press fit BB installation but none of them are the same as this BB. Most of the have the little lip that presses against the BB shell when fully pressed in or the frame takes a clip that stops the bearing when fully pressed in, this one has nothing like this?

 

Any help?

 

A generic solution to this type of problem is to find the design length of the crank axle. For instance, with Shimano Hollowtech II and Truvative cranks and compatibles, the axle length is a standardised BB shell width (we standardise it with the addition of one, two or three 2.5mm spacers) and the combined thickness of the BB cups' protrusions.

 

If you know the lengh, you'll quickly figure out how to space the BB adapters and certain ridges and/or spacers will start to make sense. What this doesn't solve is the chainline issues, but that you can tune afterwards once you know the sumtotal of spacing.

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