I'll declare a personal interest in asking this question, relating to a dispute with a national UK bicycle retailer. I'm not looking for advise on how to resolve the dispute, nor for evidence / opinion to beat anyone with a stick. In fact, ultimately the sums of money involved are negligible, and almost certainly not worth my time pursuing, so please treat the question as "more out of interest"

Bike is a hybrid manufactured by a well known global bike company, 6 months old, less than 1500 miles. Predominantly commuter riding, road and pavement (25-30 mile round trip, two or three days a week). Whilst not a BSO, I do understand the OEM components to be considered "low end" quality. Weather - typical south west UK, and of my actual commuter days I have worked out the roads will have been damp or raining on roughly 20 days over the period since purchasing the bike new. So I would consider the use of the bike to be well within "normal" use and expected conditions.

My questions:

  1. Would you be expecting to replace a low quality sealed cartridge square taper bottom bracket after less than 1500 miles riding in the conditions described above, and when making the decision on what to replace with, what would define a "quality" BB, other than relative price and brand?

  2. As above, but this time consider headset / headset bearings.

  • 2
    I think you got a lemon. If you're in the UK, you have pretty good consumer protection laws regarding fitness of merchandise, so I would raise a stink about this. 1500 miles is way to short.
    – RoboKaren
    Apr 10, 2017 at 16:33

2 Answers 2


Headsets often last the life of the bicycle. They can get "brinneled" or damaged in a crash or something, but 1500 miles is absurd.

As for a bottom bracket, on the low end, maybe 5000 miles. The basic Shimano one most people use (UN51/55/similar) can reasonably expect 10k+ miles. But sometimes you get unlucky and get a bottom bracket that lasts maybe 500 miles. You may have just gotten a lemon.

  • 2
    Headsets need to be precisely adjusted and readjusted after the initial 50-100km. A headset may deteriorate very quickly if too loose or too tight.
    – Carel
    Apr 10, 2017 at 18:39
  • OEM bottom brackets that come on many bikes sub $500 are far lower quality than even a UN26 (below the un5X).. I have seen some of them only last a couple of seasons before developing play. Some out of the box don't spin well when turned by hand. if weather is a factor then it would not be out of the question. bigger rider, pedalling style etc, many factors.
    – Paul
    Apr 13, 2017 at 14:48

Headsets do not last long when riding though wet weather with out using some sort of front fender. The water gets in there and washes out the grease. Headsets that have cartridge bearings will last longer, but will not last forever in those conditions. If you are riding through the winter and there is any road salt in play; that will destroy bearings in no time -- I live in Minnesota... when it comes to headset lasting, proper adjustment is very important ( the bearings being adjusted correctly - not too loose or too tight. Frame and fork prep is another thing that is very important and is overlooked. " A bearing is no better than it's mount" -- I read that some where...Sutherlands bicycle handbook maybe.... Most bicycle manufactures do not prep their frames very well before assembly -- facing the head tube, counter reaming the crown race of the fork --- if the bearings in a headset are very misaligned, the bearing surface is going to get damaged quickly...

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