Threaded BBs – Bottom brackets [01] - article comments

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To prevent article pages from being miles long, but preserve all the useful questions and answers provided over time, I've decided to copy/paste the website comments to the forum - and "move" further discussions here.

These are the comments from the article:
Threaded BBs – Bottom brackets [01]


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If you can't find the answer to your question in this thread, please open a separate thread with your question/problem, in an appropriate forum section (this is the Drivetrain section).

Relja
 
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  1. ericonabike
    11/03/2019 at 22:05
    Hi Relja, have you found a way to service, lubricate external bearings? Surely we could extend the bearings life with a little bit I’d lugbe…
    Thanks
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      Timothy Takemoto timtak
      30/06/2022 at 09:15
      If you purchase cheap Chinese external bearings e.g. from Ztto or other, generally colourful cartridge BBs in BB109 BB68 BSA68 bsa73 size (all the same?) which are compatible with Shimano HollowTech 2, then unlike Shimano BBs, the cheaper Chinese cartridges can be disassembled and they take standard bearings in the 6508-2RS (2RS means double rubber seal, on both sides of the bearing) size. The sealed bearings can be bashed out of the old cartridge from the back and if you have a vise, new bearings can be pushed into the cartridge, with difficulty, using an old or spare sealed bearing as a plunger. 6508-2RS bearings can be purchased for about 1USD a sealed bearing. I find that the drive side goes first so replacing the bearing (or swapping non drive side to drive side and putting a new one on the non drive side) means that instead of about 15USD a year for a new cartridge BB you can pay about 1USD a year for a new sealed bearing.
      Thanks to Relja as always for his super site. If there were more information about the meaning of “BB109 BB68 BSA68 bsa73” (which is how the ZTTO cartridge I purchased was designated, then I would be grateful. I did not really know what I was purchasing.
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      Relja Novović
      30/06/2022 at 10:00
      Hi Timothy,
      Thanks for taking the time to write this. My feedback/info:
      I had taken out bearings from an (threaded, BSD) older-mid-range Shimano HT 2 BB (newer and high-end ones have smaller cups and I’m not sure about the bearing size).
      They came out easily using a blind puller. With or without prying off the plastic caps before (I’d say that it’s recommended to pry them out first, nonetheless, but had to try doing otherwise as well 🙂 ).
      Didn’t even have to take the cups out of the frame (I worked on some old cups, and screwed them into a steel “tube” with BSA threads machined, held in a vice – to simulate cups screwed into a frame).
      Bearing dimensions are:
      25x37x6 mm
      However, I’ll have to re-measure it, didn’t write it down, as I’ve just realized (DOH! 🙂 ).
      My idea was to try sourcing some decent-quality cartridge bearings and press them into the old cups.
      If my memory (and measurements) are correct, I could try 2 variants:
      1)
      25x37x6 mm bearings, and placing the plastic caps back into place (probably a better option).
      2)
      35x37x7 mm bearings, without the plastic cups (likely to cause cranks to scratch on the outer bearing race).
      Will edit this comment once I re-measure and remember to take the note with me. 🙂
      Edit: just to confirm the measurements – 6 mm wide, definitely.
      Once I have the exact measurements and see which option works best, I’ll (hopefully remember to) post the standard model designations (along with the dimensions).
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    Relja
    11/03/2019 at 23:33
    You could pry off the dust seals, rinse them in some degreaser (mineral spirits), wipe and let them dry, then re-lube.
    Some pics can be found here:
    https://bike.bikegremlin.com/2002/types-and-construction-of-bicycle-bearings/#2
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    Christopher A. Salmons Sr.
    07/05/2021 at 06:32
    Question I just completely stripped a Roadmaster 18 Speed 26 inch wheel frame. When I removed the bottom bracket, It had 10 bearing balls on one side and 8 on the other (right). The balls were 1/4 inch, I found no trace of any cages. I took and cleaned the axle and bearing cups and then tried fitting bearings, I got 11 1/4 inch balls per side. Is this BB supposed to have 9 ball cages or loose bearings? Up until this time I have not found any information on this BB.
    • 3fd0d771d754ced79ca6b702635900b5.jpg

      Relja
      07/05/2021 at 08:59
      Hello Christopher,
      In my experience, a vast majority of bottom brackets use eleven 1/4″ bearing balls on each side (each cup).
      Bearing balls for such BBs also often come with a cage, in which case only 9 bearing balls will fit.
      Also, in my experience, some people service such BBs and put only 9 loose balls.
      I presume that they see a cage with 9 balls and conclude that to be the correct number of balls, even if they place loose balls (without a cage).
      In this case, there are 10 balls on one side, and 8 on the other side. I have no idea how and why.
      BikeGremlin CSI mode: 🙂
      Maybe someone got 2×9 balls, then miscounted on one side, and put all the balls that were left on the other side – without counting, or checking.
      Regardless of that – if 11 balls fit nicely and the spindle spins smoothly, I’d go with 11 and call it good. 🙂
      If 11 balls fit with slight overlapping, you will notice that the spindle turns roughly (as happens when there are too many bearing balls, or when the cups, or cones are severely pitted).
      In that case, I’d go with 10 balls per side.
      Relja
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    Christopher A. Salmons Sr.
    08/05/2021 at 08:02
    Thank you very much for clearing this up, I will just rebuild the BB with 22 new balls and new grease, adjust it out and finish rebuilding the bike.
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    mike
    24/05/2021 at 08:23
    i use all loose bearings on my bikes and most times i have used caged bearings they only wear in one spot and the cages usually fail and a bearing or two falls out,i aslo dont like sealed bearings,loose bearings roll much better and they are cheap to replace.years and years ago all bikes had loose bearings,cages were only made to make it easier to install,they serve no other purpose
 
  1. mike
    01/07/2022 at 18:13
    if your not sure how many loose bearings were in a wheel or crank i just fill up the whole space then remove one bearing sometimes two bearings but usually removing just one does the trick also dont over tighten on loose bearings as they will also run rough and grind away
  2. e997f8b7bd00e2fb80564fd7249af830.jpg

    Christophe
    31/10/2022 at 10:57
    Hey Relja
    You’re explanations are super clear as always !
    I was wondering if you explain somewhere the differente lenght of the square taper axles. I would like to buy one but there is a wide variety of size around… 107 to 127mm… Which one for what ? Is it important ?
    Also in the end are JIS, and ISO completely compatible ? Should I take care of that when I mount old cranckset on various bikes or it doesn’t really matter ?
    I was amazed to realized that your website is now big enough so I need to use the research function. Nice job !
    Thx for your answers !
    Christophe
 
This topic is closed for further replies.

If you can't find the answer to your question in this thread, please open a separate thread with your question/problem, in an appropriate forum section (this is the Drivetrain section).

Relja
 
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