Pressfit BB tips

timothyw
timothyw Posts: 2,482
edited July 2014 in Workshop
Hi All
Had my bottom bracket explode on the club run today - fortunately managed to limp home in the little ring.

Unfortunately bottom brackets are rather a mystery to me, particularly the pressfit variety!

The bike specs list is as BB86 pressfit (sometimes referred to as PF86 I understand) - it's a Fuji Sportif 1.1 2014

Is it just one of these that I need?

http://www.chainreactioncycles.com/sram ... -prod75586

Presumably I then just need to hammer out the existing BB, and gently tap in (with block of wood) the new one?


Second question, I've been contemplating replacing the frameset with an On One Dirty Disco or perhaps Kaffenback 2 (both BSA threaded) - would this require me to replace the chainset/crankset as well as the bottom bracket? Is there such a thing as an adapter to fit a BSA bottom bracket into a PF86 frame, or vice versa? I'm guessing probably not due to the added diameter (and lack of resistance with anything to screw into)?

Cheers all!

Comments

  • dj58
    dj58 Posts: 2,217
    Hi Tim,

    If your existing pressfit BB is an FSA like the one in your link and you are replacing like for like, them that should be fine. As to the removal of the old unit, yes you can drift it out, just be careful not to damage the bb shell.

    As for fitting the new one, you don't want to be hammering the new one in with a block of wood, yes you could probably do it that way, but you will damage the bearings which will lead to your BB failing prematurely.

    There are tools available for pressfit BB's however they tend to be expensive for what they are. You could make your own as has been done before by people on BR, Have a read of these links

    viewtopic.php?f=40004&t=12950137&p=18635811#p18635811

    http://www.parktool.com/blog/repair-hel ... et-service

    If you swop your frame for one with a treaded BB shell then you will need a corresponding threaded type BB. Whether you could use your existing crankset would depend on whether the axle length and diameter were compatible with the particular BB's specification. Shimano Hollowtech II cranks work with Shimano's external threaded type and pressfit BB's.

    FSA make this adaptor for BB30 to BSA BB, don't know if they make one for BB86 though.
    http://www.wiggle.co.uk/fsa-bb30-conversion-kit/
  • Monty Dog
    Monty Dog Posts: 20,614
    If you've been riding in wet conditions without guards then any external BB isn't going to last too long if you put the bike away with a seat-tube full of water. I have BB86 on 2 bikes - a CX bike and MTB and they've been fine.
    Get your LBS to fit a replacement - you can easily damage the bearings by pressing too hard on the inner race.
    Make mine an Italian, with Campagnolo on the side..
  • mrkev83
    mrkev83 Posts: 184
    Not still under warranty?
    http://www.strava.com/athletes/mrkev83

    Built for comfort... Not for speed
  • timothyw
    timothyw Posts: 2,482
    Well, maybe, but to be fair I think I'd be pushing it getting Evans to swap the Bottom Bracket after around 9 months and nearly 3000 miles. Plus it's a hassle getting there.

    Anyway, for what it's worth I managed to hammer out the old bottom bracket cups with a large amount of brutality (it's an Alu frame that I have no great love for - I dread to think what it must be like getting push fit BBs out of nice carbon frames), and have now ordered the Shimano pressfit tool - TL-BB12 - from Rose bikes (along with a new BB72 bottom bracket):

    http://www.rosebikes.co.uk/article/shim ... aid:341005

    This seems to be much better value than all the alternatives I've come across (well, excluding the block of wood and hammer/desk vice).
  • dennisn
    dennisn Posts: 10,601
    TimothyW wrote:
    ... and have now ordered the Shimano pressfit tool - TL-BB12 - from Rose bikes (along with a new BB72 bottom bracket):

    http://www.rosebikes.co.uk/article/shim ... aid:341005

    This seems to be much better value than all the alternatives I've come across (well, excluding the block of wood and hammer/desk vice).

    A much better choice than a hammer / wood block. :wink:
  • timothyw
    timothyw Posts: 2,482
    Argh, fecking bottom bracket isn't compatible with the chainset - fits fine on the drive side but other side needs stupid star shape fitting (as depicted in the first BB I linked.... This was not obvious from the original bottom bracket as that side had exploded), and to compound the situation the bastard crank arm (which came off with barely a wiggle last week) will not shift (I managed to fully tighten the fecker before noticing the play) and it seems apparent that when I bought the bike it didn't come with the self-extractor crank cap.

    So now I have to -
    - buy a new bolt cap to get the crank arm off the crankset.
    - buy a shimano crankset that does fit the new bottom bracket that I've just fitted.
    OR
    - remove the brand new (thankfully cheap) bottom bracket that I've just fitted (probably destroying it in the process), and get the correct GXP one.

    Bugger.
  • patrickf
    patrickf Posts: 536
    A GXP chainset has two different sized cups as you've found out.

    If you do have a Sram chainset then you'll want this BB: http://www.wiggle.co.uk/sram-bb86-gxp-p ... m-bracket/ or another compatible one.
  • dilatory
    dilatory Posts: 565
    For what it's worth and I hate to sound like that guy, but maybe if when you have the BB replaced you should keep it a bit cleaner!

Categories