I bought as bottom bracket tool some time ago, a generic Shimano one. sometimes with some sealed bottom brackets from ZTTO it worked beautifully. Sadly in the process of restoring a 98' Kona Caldera, and also fixing some noises from the bottom bracket of my old road bike (photo attached), I've noticed my tool, which is supposed to be a Shimano compatible one, doesn't always fit. The Kona has a Shimano BB-LP26, and the drive side fit nicely, but the other support cup doesn't. Luckily it was finger locked and easy to clean and service. But the one of my road bike doens't fit in every side, it seems like exist an other Shimano BB, but I was not able to find anything on the internet. Long story short in some BB it works nice, in others simply doesn't. Do you know what's happening here?

btwin 09' sport 1 bottom bracket

  • In which way does it not fit? Cannot be inserted? Is loose? The splines are wrong in number? Kinex makes pretty normal BB cups I think. Nov 20, 2020 at 16:07
  • Can you show us the tool ?
    – Criggie
    Nov 20, 2020 at 21:37
  • I've encountered at least a half-dozen different schemes for securing square taper shafts. Nov 21, 2020 at 1:29
  • Last year I installed a BB-UN26 into my old bike and used one of the cheap generic tools, but the plastic (non drive side) cup, had thicker material which reduced the various diameters, so the tool did not fit on that side. With a bit of patience and elbow grease I filed down the "teeth" of the tool and used a rotary tool to remove a bit of material between the teeth, until the tool fit into the plastic cup.
    – user39927
    Nov 21, 2020 at 15:38

1 Answer 1


I bought one of these tools.

enter image description here

The problem with it is 'cheap and nasty rubbish'.

The tool does not fit into the plastic cup (which in my case was an Octalink, not a square taper, not that it matters too much) on the NDS at all, but as you say fits into the metal drive side ok(ish).

I looked on Amazon and found many similar complaints for these cheap, poorly made tools.

I replaced it with a Park Tool BBT-3.2, which fit perfectly on both sides, and the plastic cup came out easily.

Shimano have two tools, the longer TL-UN66

enter image description here

and the shorter TL-UN74-S

enter image description here

Park Tool's BBT-22 & BBT-32 are respectively based on these.

There are many reports on the poor quality of generic BB tools on Amazon, which allows any random rubbish with little or no quality control to be sold (as do Ebay and AliExpress), e.g.:


There are lots of brands selling 'ISIS' BB tools, and any brand which is big enough to have a website, e.g.. IceToolz, FSA, Topeak, Unior, Weldite, is likely to care enough to make a tool that actually fits into the thing it's supposed to be fitting. My eyes suggest that the cheapo tool has splines that are wider than they should be to fit in the cup, but the real answer is 'it's poorly made rubbish'.

Photo for comparison:

enter image description here

Suggest to replace with any branded (real brand, not fake from some Chinese dropshipper on Amazon) BB tool

As it turned out my BB was rusted very hard into the bottom bracket shell. I eventually found a local mechanic (I am in Indonesia) who mostly works on cars, and he had a tool very similar to my cheapo one. I did not examine it closely, because I had already removed the NDS cup. However it is likely it is the same - it could be that it was a better version (perhaps not every such tool is as poorly made each other, even coming from the same factory). But I don't know, since we only were working on the DS. After pressing very hard against an unsecured BBT-32 I managed to damage the teeth as it slipped repeatedly. I would not recommend using any such tool without first fully securing the tool against the bottom bracket, as even a quality tool can be damaged in this fashion. The cheapo type tool we secured using a long bolt through the bottom bracket spindle and washers. Since the BBT-32 has a wide opening, you need a larger diameter washer than you would for BBT-22 or similar.

  • You cleared everything! Thank you, I'm gonna buy a proper tool, I have the exact same you showed in the first pic, I don't want to mess with the bottom bracket by forcing or stripping the teeth.
    – Marras93
    Nov 21, 2020 at 16:29

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