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Compatibility [10] Bottom brackets

This post will explain bottom bracket compatibility. Which bottom brackets (BBs) can be combined with which crankset standards.

Before you start, to avoid any misunderstanding:
please take the 5 minutes needed to read the compatibility articles use instructions.

Posts that explain in detail the history and construction of each BB standard can be found here:
1 History and threaded BB standards
2 Threadless (press fit) bb standards
T47 – a new threaded BB standard

Note: crankset for mounting on externally screwed in bearings, with a hollow axle 24 mm in diameter, is compatible whichever manufacturer produces it. So: Race Face X-type, FSA MegaEXO, Truvativ/SRAM Giga X Pipe (GXP), Campagnolo Ultra Torque – they are all compatible with Shimano Hollowtech II standard, so only Hollowtech II will be named in tables and remainder of the post.


1. Compatibility of bottom brackets

Table of BB standard and compatible cranksets of different standard (all the BBs accept the same standard cranksets, of course, others require an adapter, as is explained in chapter 3):

BB standardCrankset compatibility
Threaded (brit, ital.)square taper, ISIS, Octalink, Hollowtech II, BB386EVO
The first 3 require BB cartridge of their standard to be installed. HTII and BB386EVO require HTII BB shell
1 a) BB30Hollowtech II, BB386EVO,
1 b) BB30AHollowtech II, BB386EVO, BBright, BB30 if they have spacers on the left side
2. PF30, OSBBHollowtech II, BB386EVO, OSBB, BBright, BB30
3. BB86, BB90, BB92Hollowtech II
4. BBrightHollowtech II, BB386EVO
5. BB386EVOHollowtech II, BBright, OSBB, BB30 if the spindle is long enough
6. BB90, BB95Hollowtech II
7. PF86, PF92Hollowtech II, BB386EVO
   T47All – if the spindle length is appropriate


2. Compatibility of cranksets and different BBs

Table of crankset standards and compatible BBs (all the cranksets are compatible with the BBs of the same standard, of course, the others needing a special adapter):

Crankset standardBB compatibility
Square taperThreaded (british, italian)
OctalinkThreaded (british, italian)
ISISThreaded (british, italian)
Hollowtech IIThreaded (british, italian), BB30, BB30A, PF30, OSBB, BB86, BB90, BB92, BB95, BBright, BB386EVO,
BB30PF30, OSBB, BB386EVO if it matches the spindle length, BB30A if the crankset has spacers on the left side
BB30ABB30 with use of spacers on the crankset
PF30/
OSBBBB386EVO
BB86, BB90, BB92/
BBrightBB30A, PF30, OSBB, BB386EVO
BB386EVOAlso available as threaded (British, Italian), BB30, BB30A, PF30, OSBB, BBright, PF86, PF92
BB90, BB95/
PF86, PF92/
T47Fits all the BBs – if the spindle length and diameter match the required for the BB used


3. Combining different standards

There are several adapters made by various independent manufacturers that can match certain BB standards with certain crankset standards. They are usually placed directly into the frame, replacing the “standard” BB bearings. Solutions vary from case to case.

Praxis Works' adapter to fit 24 mm spindle diameter cranksets in a PF30 compatible frame cartridge shell.
Praxis Works’ adapter to fit 24 mm spindle diameter cranksets in a PF30 compatible frame cartridge shell.
Clicking on the image opens Amazon affiliate link with a bottom bracked adapter search.

Amazon.com search of bottom bracket adapters (as an Amazon Associate, I earn from qualifying purchases).


4. What to pay attention to when buying bicycle, cranksets, or BBs?

In terms of both BBs and cranksets, of course. There are so many (in)compatible standards and how not to get confused or get mismatching equipment? Just follow these simple steps:

  1. Always check for the frame you have, or are planning to buy, what standard of BB does it’s BB shell have. Pay attention to all the details.
  2. If buying a BB, make sure it fits the frame BB shell (as determined in step 1).
  3. If changing cranksets
    BB30 and PF30 cranksets won’t fit frames with different BB shell standard, because their spindle will be too short.
    Cranksets with 30 mm wide spindles won’t fit into frames with BB86, or BB90 BBs, but with correct BB some can be made to fit into threaded frames.
    Cranksets with 24 mm spindle diameter are the most versatile and, with the right BB, or adapters, can fit almost any frame.
  4. Cranksets with 24 mm spindle diameter are not all the same! SRAM and some other manufacturers make spindles that are 24 mm wide at one end, and 22 mm wide on the other, so the correct matching BB needs to be acquired.
  5. If the frame has a press-fit BB shell (without threads, threadless), then you need quite expensive, special tools to install and remove/change BBs. If not using such tools (like a bearing press), bicycle frame can be damaged.
    On the other hand, threaded BBs allow the use of simple, inexpensive tools.
  6. When it is all set up correctly, differences between different BBs (e.g. stifness) are never perceivable when riding the bike – basically they are unimportant. So there is really no need to buy a frame with a certain BB standard because it is marketed as stiffer, better. Just see what kind of frame you like, or what components you already have, and go for the simplest, easiest, cheapest solution to make it all work.


5. Author’s personal opinion

For ease of installation and replacement, threaded BBs rule!  🙂

Square tappr and Octalink BBs are by far the most durable, long lasting ones.

New T47 standard looks promising, but still not enough first hand experience data to confirm durability and ease of maintenance.

Related post – Bicycle cranks (“crankset”) compatibility:

Bicycle crankset compatibility (cranks, chainrings)
Bicycle crankset compatibility


Compatibility posts are also available in eBook (printable and Kindle) and paperback editions on Amazon:

Bicycle drivetrain compatibility book
Bicycle drivetrain compatibility book

21 thoughts on “Compatibility [10] Bottom brackets”

  1. Hi does anyone know what cranksets will fit a shimano BB70 bottom bracket please. Im really stuck in finding information that will help me decide what cranks to buy.

    Reply
    • That is Hollowtech II BB, right?

      In that case, the options are:
      – Square taper BB installation and square taper cranks.
      – Octalink BB installation and Octalink cranks.
      – Hollowtech II (as the noted BB70) BB and cranks with a spindle width of 24 mm, including of course the Hollowtech II cranks.
      – Special BB that allows for 30 mm wide spindle to use with BB386EVO and BB392EVO.

      So, in addition to the above noted, cranks that can fit are:
      Race Face X-type, FSA MegaEXO, Truvativ/SRAM Giga X Pipe (GXP), Campagnolo Ultra Torque.
      – As long as a compatible BB cartridge is used.

  2. Hello I’d like to know if there is any possible way of using my sram sx powerspline cranks on a shimano hollow tech II bottom bracket, like is there any adapters or anthing I could use.

    Reply
    • PowerSpline bottom bracket (Amazon affiliate link) threads into frames with English thread BB shell (like Holowtech 2 BB cups are threaded in).
      In other words, there’s no need for an adapter – Power Spline BB threads right into the frame (unless the frame has some exotic thread).

      It’s not what I’d call a good, high-quality design, but if those are the cranks of choice, that is the BB needed to mount them.
      With a note to mind the chainline. Different BB cartridge axle lengths are suitable for different frames, with different chainlines.
      Bicycle chainline explained

  3. Hi! Thank-you for this wonderful website.
    I have a SRAM Rival 1 42T 11-speed crankset on my bike. Unfortunately I damaged it and need to replace it. The bottom bracket is an FSA Mega EVO which is a threaded bottom bracket that meets the BB386EVO standard. SRAM offers their cranks in two standards: BB30 and GXP. From your helpful tables I deduce that I need to order the BB30 crankset to work with the BB386EVO bottom bracket. Is this correct? Any advice? Thanks in advance.

    Reply
    • Hi,

      BB30 cranks should fit BB386EVO BB, if the spindle length is matching.

      I’d check with SRAM to be sure if it fits. They might need the info on the frame’s BB shell width (left-to-right width, not the circle diameter), and the rear chainline of the bike.

      But if you have a threaded bottom bracket, you could go with a threaded SRAM GXP BB, and GXP cranks.

  4. Can I just replace spindle length on the Cannondale Hollowgram SiSL2 Crankset BB30 to fit on BB30a. Or is there an easier/better way?

    Reply
    • Hi Marko,

      For all I know:
      Spindles are not replaceable on a vast majority of cranks, so I’d be amazed if that were possible.
      But you should be able to fit BB30 cranks on a BB30A frame if the cranks have some spacers (that should be removed in order to fit on the BB30A frame).

      Relja

  5. Hi There I am riding a Specialized Sirrus X 5.0, and the current bottom bracket is a Praxis 68-0201B , 68mm BSA , with Praxis Alba Crankset 1 X 11.
    I have purchased a Shimano GRX 810 Gravel 1 X 11 that runs on Hollowtech 11 bottom bracket.

    Looking at changing BB to XT MT800 sized 68/73mm – English Thread – 24mm or the SHIMANO XTR M9000/9020/980 THREADED BOTTOM BRACKET.
    Question i’m asking, does either of these BB fit my current frame and are compatible with the GRX Crankset
    Or what Bottom Bracket do i need to fit the Sprcialized frame, as the current bottom bracket has not much detail stamped on it, i believe it is a Praxis one though.
    Any advice on this would be greatly received.
    Regards
    Kevin Taylor

    Reply
    • Hi Kevin,

      Short answer: yes, either should work.

      Long answer:

      In terms of the BB fitting the frame:
      You have a 68 mm BSA bottom bracket, so your frame uses the British standard threaded bottom brackets (and is most probably 68 mm wide).
      Hence – any BB that has the British standard thread should screw in without problems.
      Now, many BBs are designed to work with both 68 and 73 mm wide frames, but not all – check before buying.

      In terms of the BB fitting the cranks:
      Any Shimano Hollowtech II compatible BB should work.

      A budget option is Shimano Tiagra BB-RS500.

      Relja

  6. Enjoying reading your site…very informative. I have the following BB Compatibility question. I’m updating the BB’s (tapered steel spindles w/ caged bearings) on two of my 1980’s steel frame rides, one a two-chainring road bike & one a 3-chainring tour bike. I want to replace with the more current threaded, tapered spindle, cartridge/sealed bearings. The two spindles are “eccentric”…each has a longer dimension(on the right/drive side) from the bearing surface than the left side. From all the info/specs I’m finding, none of the offerings spec an eccentric spacing, just the overall length (such as Shimano UN300). I think the original idea was to allow for specific chainline alignment. Will any of these products work without chainline “problems”. Thanks for your input.

    Reply
    • Hi Steve,

      In my experience, the first thing to pay attention to is the frame’s BB shell threading standard. Making sure which one it is, before trying to screw anything in. I know it may sound silly, but I think it’s worth stressing for anyone reading this.
      The article “Vintage bicycle frames with modern parts” deals with this in great detail.

      As for the cartridge bottom brackets – all the spindle eccentricity is dealt with within the enclosed mechanism, so it is less plain to see, but it still exists.
      Unfortunately, it’s difficult to know upfront which length will be the optimal choice. For all I could try, it still boils down to trial and error. I make sure to always have the entire range of lengths in the shop and am happy to do test-mounting to confirm, starting with the length I expect to be the optimal choice first.

      At the end of my bicycle chainline article, there’s a chart that gives some left and right eccentricity data, but it won’t help much. Many cup and cone axles (spindles) have a slightly different taper compared to Shimano’s cartridge BB square spindles. That’s mentioned in my threaded bottom bracket standards article – chapter 4 (JIS and ISO standards for the taper slope).

      So it’s mostly eyeballing and trial and error. Some very rough guide (what I often try with first) would be:
      110 mm spindle for singlespeed cranks.
      113 to 115 mm spindle for double cranks.
      120 to 128 mm spindle for triple cranks.

      Maybe this isn’t much of a help, but it’s the best I can do. Coming up with a system to know upfront which spindle length fits best would save me a lot of time and hassle, but I still haven’t managed to do that. I get it right from the first time about 50% of the time, and from the 2nd try (with a longer spindle most often) about 40% of the time. But sometimes it takes 3 tries to get it right. On the upside – it is quite a Zen-like procedure, no-hassle once the old BB has been removed. 🙂

      Relja

  7. Relja…thanks for your prompt & thoughtful reply, very helpful. I never thought that BB’s would be such a problem…but eventually I think I’ll be able to work out a solution. IRD does list a spindle selection that includes the cups and 1/4″ caged bearings and shows the asymmetrical spindle with left/right “offsets”… that may be the best solution, although more expensive than their cartridge bearing alternative. Thanks again…your site is very helpful!

    Reply
  8. Hi i have a road bike with BB72-41B road bike BOttom bracket. I believe this is an ultegra

    My question is can I install a BB71-41A (deore) or a mt800 (xt) BB on a 105 crank? Seems like they have same specifications except the inner sleeve width? Will they fit if i dont use the inner sleeve? (sealed frame)

    Reply
    • Hi Vendmerc,

      Based on Shimano’s specs, the BB71-41A is too wide – designed for 89.5mm and 92mm wide frame bottom bracket shells.
      Road bike cranks generally work with 68 to 73 mm wide frames.

      The Deore BB, model BB-MT800 (XT M8000 Series) should fit road frames and cranks fine.

      Generally speaking – for the 105 cranks, it is important that BB is for Hollowtech II, and that its width matches the frame (probably 68 mm, but, as I like to say: “one good measurement is better than a thousand expert opinions”). 🙂

      Relja

  9. Hey, I have a road bike with a BB30 Bottom Bracket I was wondering if Hollowtech II Cranksets. The bike is a Specialized Allez Sprint

    Reply
    • Hi Rust,

      There is enough room for a 24 mm in diameter Hollowtech II axle inside the BB30 brackets and bearings. But you need an adapter.
      Here’s an Amazon affiliate link for a BB30-Hollowtech II adapter.
      I suggest you look for an adapter in a local bicycle shop – keeping them in business and keeping a good relationship with LBS-s is priceless.

  10. Hi Relja,
    I have a question, I have TruVativ FC-E350-A1 and this cranksets have a power spline and Square BB compatibility i want to change that crankset but i can’t find the compatibility list or something. This crankset is compatible with 3×8 derailleur and i need 3×8 comp. crankset,
    So which crankset is ok with my bike’s BB?
    Is shimano Acera FC-M361 48X38X28T crankset ok for me? or which is the best Shimano crankset is comp. with my BB?
    If you answer my question im really glad for that thanks for now.

    Reply
    • Hi Metin,

      Generally:
      Shimano Acera FC-M361 works with square taper bottom brackets.
      If your bottom bracket isn’t a square taper one, you’ll need a square taper bottom bracket (122.5 mm long spindle, in most cases, for that model of cranks – for details on this see my bicycle chainline article).

      Regarding the number of speeds, you can also use 7-speed, or 9-speed cranks, they will most likely work fine (noting this because of the parts shortage, in case you can’t source 8-speed cranks).

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