ok, never heard of the middleburn crank failures but their rings used to be significantly better than the shimano ones.
Saw quite a number aside from Trail_rat's experiences above, also never got on with their rings, lasted well, didn't shift that well. Always just used Shimano (or TA).
I'm still using square taper in my commuter, the lifespan on cheap shimano sts is better than on expensive externals IME. But the difference isn't massive and the other benefits of external mean I'm ht'd on all the proper bikes.
(incidentally I remain pretty convinced that the main reason some people get terrible lifespan from shimano BBs but much better from Hope is just that Shimano have no tolerance of gorilla-tightening while Hope do. XT is a very good product these days.)
TurnerGuy - Memberok, never heard of the middleburn crank failures but their rings used to be significantly better than the shimano ones.
Maybe so but they never moved on, compared with the modern competition middleburn rings are pretty rotten now- expensive and pretty shortlived, and only adequate shifting.
I never saw what was wrong with square taper quite frankly.
Bearings were fine, it was the cranks that attached to them were usually the problem. Impacts and pedaling forces (torque one way then the other on one crank, LHS for me) killed the tapers in all my Al cranks. Saw a few too many sheared axles but only among people doing bigger stuff than I ever did.
I gave up on Shimano external BBs for the MTB and got a King. Pricey, but so is a good square taper BB and chainset combo and a Hope/King BB and HT2 crank set up feels more solid. I'd use square taper on a long-distance tourer though.
Another here who's never strayed from the square taper path. Usually last 10 years in all sorts of awful conditions, and I'm over 100kg and yet to break one.
just walk backwards in to the sea, things are nicer that way.
Glad to be away from square tapers on mine. I had never ending problems with middleburn cranks. The tapers are machined and not smooth and would always work loose. Used Hope BB's, Race face and Royce. The wife has some very short xt cranks on one of her bikes with a Royce fitted and runs very smooth. But she doesn't make the bike work as hard. I used to find the bearings would break up and collapse. Syncros forged were the only cranks I never really had an issue, but by then, I had a load of broken BB's, which I just gave up on. Shimano BB's when they did the UN92 were great, but now they don't exist. I have got through a few external BB's but only shimano ones. The hope ones seem to last adequately, king fares a bit better, with being greased once a year and the Uberbike one just seems to roll round. The wife has a BB30 on her road bike, so that's another questionable life expectancy !! I still believe square tapers faded for reliability , weight and ease or servicing/ replacement. I remember seized BB's, cranks with iffy threads. All now in my past
Facing you bb shell is more important with an external bb. Maybe that's why some of you have had bad experiences.
My hope external bb has outlasting anything I've had before!
Square taper defiantly had more drawbacks.
External bb's are a step forward!!
We have Shimano UN somethings on our heavy tourers and on my wife's commuter (in fact that bb is on its second frame now) with zero issues. In contrast I seem to be forever changing the external BB on the other bikes. Might be lighter, might be stiffer (though I can't feel a difference) but for longevity the internal ones are infinitely better IME.
there's barely anything in it! External are marginally stiffer and slightly easier to fit (if your BB is well faced, that's a big IF, how many of us have BB facing tools at home?). I have broken 1 square taper BB and 1 chainset but they were both cheapo OEM items, I didn't break a shimano one just as I've never broken a shimano HT2. Square taper bearings definitely last longer tho, whether that is an important factor varies from person to person.External bb's are a step forward!!
