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My road bike bottom bracket which has seen some roughly 6000km and one winter with lots of wet and salty roads and some freezing has developed some noticeable play now. It's still running smoothly and does not creak but has some non-negligeable side-to-side wobble so that I think about replacing it. However, I fear that another 5000km and another winter down the road, I will be in the same spot as I am now.

Therefore I am trying to find out which characteristics I should look for when shopping for a new bottom bracket. E.g. should I sacrifice some performance in favour of better sealed bearings, will ceramic bearings last longer since they aren't affected as much by corrosion...

For the sake of completeness: currently some standard Shimano press-fit bottom bracket for hollowtech cranks is installed.

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    5000 km is good run for any part as cheap as a BB
    – Paul H
    Commented Jul 8 at 19:52
  • For winter use I would say "ease of replacement, cost and availability" are the three most important attributes. A threaded shimano Hollowtech2 bottom bracket system is not a bad option. The pressfit version is more time consuming to replace and maybe another option would suit better.
    – Noise
    Commented Jul 12 at 18:15
  • @Noise true in general. Unfortunately the frame is built for press-fit, so threaded seems to be not an option in my case...
    – Benedikt Bauer
    Commented Jul 13 at 9:18

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None of my Shimano BBUN300s have lasted more than 5000km when winter riding is included. These are "sealed" square taper units, so 6000km sounds acceptable if it is a cheap square taper you are using. For square tapers, it does not take many(<100) kms from a slight wobble to total failure in my experience. The first symptom is often chain rubbing periodically on FD in the "senstitive" gear combinations.

I have just accepted that 5000km is what my BBs can last when i ride through the winters. Others might have better experience with other types, but riding style and weather affects the results to a large degree. A 50 kg spinner riding through dry winters is not comparable to a 90kg grinder riding through wet salty slush 3 months a year.

I have no faith in ceramic bearings. The salty slush will degrease the bearings which accelerates wear, and if that does not kill it permaturely then influx of dirt will. In either case I doubt ceramics by itself does much better. Better seals/build/grease on the other hand probably does matter.

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