Question about bottom bracket Facing and Tapping- Mtbr.com
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  1. #1
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    Question about bottom bracket Facing and Tapping

    Hi all.
    I have a 2008 Kona Stinky which i got in March. Hopefully in a couple of days i will be buying a raceface Evolve DH crankset for it. After reading the installation manuals from the RF website, it says that the bottom bracket shell needs to be tapped and face to remove welding splatter and/or paint from threads and face. My question is, does the BB shell need to be tapped and faced everytime a new BB is installed or is it only needed when the frame is new? would mine need to be done, seeing as its only a couple of months old? I would get it done if it is necissary at my LBS but i dont have high hopes on the guy doing it, The guy's stupid, overpriced and slow as all hell. ( wanted $150 from my mate to build a front wheel for him, and he said it would take over a Week )
    I would buy the tool to do it myself, but nearly had a heart attack (At 16 yo) when i saw how much a parktool tapping and facing tool costs ( $1200 , what makes these things so darn expensive??) from chainreaction cycles. If it is absolutley necissary to have the shell taped and faced, ill ask the guy at my LBS to do it and if he cant im stuffed, caus the nearest city that has shops that could do it is over 500km from where i live. Can people tell me if they have installed the BB without facing and tapping the shell and if they did, did it cause the BB to violently explode and kill everyone in a 25m radius?
    cheers

  2. #2
    Err
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    You should not need to chase (tap) the threads or face the BB again unless when you pull out your old BB, you find that the threads are all messed up. Just replace the BB, should be good to go.

    Also, be careful not to cross-thread your new BB when installing. Lots of people do this and end up needing their BB tapped to fix.

  3. #3
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    other than having screwed up threads there is no reason for tapping the bb shell. The same goes for needing to face it, if you still have doubts, take your bb off and get a pic of the face of your bb shell and post it on here.


    The tools for tapping, facing and reaming cost so much $$$$$ because they are very precise and are also made out of very very durable materials.

  4. #4
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    Kona, like most all companies, faces their BB shells before sending them out. So unless you've managed to screw up the threads all you need to do is install the BB.

  5. #5
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    There is no damage to the threads and the black marks on the face is just paint that came off when i undone the BB, the metal itself is not gouged, chipped or damaged. So wat u guys think? am i all good to install the new BB? And dont worry, im always now extremely carefull about making sure i dont crossthread the BB (found out the hard way on me old XC bike

    Here are some pics
    Attached Images Attached Images

  6. #6
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    You are fine, facing just ensures the bearing cups are perfectly parallel to each other (even distribution of load and stress) and maximize the life of them. You should be able to install the cranks without ANY problems whatsoever.

    Cheers

  7. #7
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    Quote Originally Posted by NicKKo
    There is no damage to the threads and the black marks on the face is just paint that came off when i undone the BB, the metal itself is not gouged, chipped or damaged. So wat u guys think? am i all good to install the new BB? And dont worry, im always now extremely carefull about making sure i dont crossthread the BB (found out the hard way on me old XC bike

    Here are some pics
    Wow, looks like Kona's decided to cut that corner. As of 2006 all their frames were sent out faced.

  8. #8
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    Hummm...."facing" means that the flat area around the threads has been smoothed out and taken down to bare metal. Yours is covered with paint, some of it is chipping. I wouldn't call that flat.

    I woud suggest taking a plastic scraper and chipping the paint off. Or a razor blade if you're extremely carefull not to remove metal. It should be very flat when you look at it from the side. Then just hope the metal is straight.

  9. #9
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    ur in luck.....just attach cranks and go
    the trick is ENJOYING YOUR LIFE EACH DAY, don't waste them away wishing for better days

  10. #10
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    I would seriously consider chasing/facing any frame that is going to receive external BB type cups. The facing removes the paint AND any metal distortions from manufacturing. The facing tool (part of the Park Tool Kit) is designed to make both sides of the shell perfectly parallel. That is the biggest killer of external BB is a non-parallel mounting.

    Any non-external BB it is not as crucial, but important nontheless.

  11. #11
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    Quote Originally Posted by Demo-9
    I would seriously consider chasing/facing any frame that is going to receive external BB type cups. The facing removes the paint AND any metal distortions from manufacturing. The facing tool (part of the Park Tool Kit) is designed to make both sides of the shell perfectly parallel. That is the biggest killer of external BB is a non-parallel mounting.

    Any non-external BB it is not as crucial, but important nontheless.
    Not that I dis-agree with your enthusiasm for facing, but I dont buy into the need to face with an external bb more than a non-external bb. Every bb (except the old RF taperlock) is tightened against the face of the bb shell. The plane that the bearing rotates in is still dicatated by the bb face whether the bb is external or not. I would also add, that the angular difference in the two face planes (outside of some very poor QC) would be well within the tollerance of radial cartrage bearings..with any bb. Lastly, the majority of external BBs use a plastic sleeve between the spindle and bearing...allowing some 'give' in the perpendicularness required between the two parts.

    IMO the biggest killer of external bbs is two (or maybe three) fold.
    One is simply small bearings that are not designed to take the type of loads that bbs see. The large spindles reduce the ball size dramatically from what 'could' be used in the cups of external bbs. Radial cartrage bearings are designed for high speed, radial-only small loads this is exactly what a bb is NOT. BBs see quite high loads, they turn very slowly, and see significant axial loading.....
    Second (and third to some extent) are exclusive to RF. Their 'descrete' bearing adjustment on thier external bbs is severly flawed from an engineering standpoint. You have to add or subtract beairng pre-load in 1/2 mm increments only.

    Try to adjust your headset with ONLY full turns of your cap bolt....see how long your headset bearing last.....

    lastly, RF uses full complement bearings (they have more balls and no cage) in their BBs. These type of bearings have a higher radial load rating (see above for the relevance of this) but at the same time have less 'room' in the cartrage for grease. They also have no 'extra room' for contaminants to 'go to'. What you end up is a bearing that is less well lubricated and forces dirt and grime to be in the bearing path more than a non-full complement bearing.



    To the O/P, My personal suggestion would be to very carefully remove the 'paint' from the face of the bb shell with a razor blade. The paint will most likely flake off in large chips as it is powder coat, not actually paint. This will allow the BB to sit agians the metal of the frame (that was faced as some point in production) rather than the un-even paint surface.

  12. #12
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    Quote Originally Posted by davep
    Not that I dis-agree with your enthusiasm for facing, but I dont buy into the need to face with an external bb more than a non-external bb. Every bb (except the old RF taperlock) is tightened against the face of the bb shell. The plane that the bearing rotates in is still dicatated by the bb face whether the bb is external or not. I would also add, that the angular difference in the two face planes (outside of some very poor QC) would be well within the tollerance of radial cartrage bearings..with any bb. Lastly, the majority of external BBs use a plastic sleeve between the spindle and bearing...allowing some 'give' in the perpendicularness required between the two parts.
    Good points. I still think that an external bb set-up is slightly more in need of a good face compared to non-external. The lockring on a non external serves a purpose differently than the inner sleeve edge of the bearing side of an external bb that butts up to the bb shell.

    I always chase n face every new frame I get just because my shop has the Park tool.

  13. #13
    TLL
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    Quote Originally Posted by Demo-9
    Good points. I still think that an external bb set-up is slightly more in need of a good face compared to non-external. The lockring on a non external serves a purpose differently than the inner sleeve edge of the bearing side of an external bb that butts up to the bb shell.
    .
    The alignment of the L/Right threads with respect to each other is more important and will ultimately determine whether the bearing cups are parallel. It is nice to have the shell facing parallel tho.

    RF got the terminology wrong . . . it is chasing and facing. OP is good to go.

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