I have had three or four of these because they were cheap, it turned out that in the long run it was cheaper to save up and buy a decent bottombracket. Everyone of these that I bought broke in under a month, the same two faults occured each time. 1) Mud and grit easily get past the seals and wear out the bearings causing them to cease or rattle. 2) The ends of the tapered arms round off very easily, even during light XC and commuting use I have rounded them off. Steer clear and buy a decent bottombracket, or even better get the new external type, or if your into jumping and DH get some 3piece cranks. ...
Advantages: Cheap, extremely durable, abuse tolerant Disadvantages: Poor crank choice, may not be suitble for extreme use
What's this?
It is a JIS square tapered BB. And in english...
BB - bottombracket. Screwed into the frame and serves as a mounting point for your cranks.
Square taper - Axle shaft of the bottombracket is tapered. The shaft is wider at the base than it is at the tip, so it ensures a very tight fit when the crank is tightened up. It fits square holed cranks only.
JIS - Japanese International Standard. This is a measure of the degree of taper. There is also the ISO standard used by European manufacturers, such as Campagnola. The vast majority of mountain bike cranks are JIS. An ISO crank may or may not fit a JIS square taper BB depending on the tolerances and amount of wear.
Evolution or Devolution?
In the last few years BB's have undergone something of a revolution. Octalink from Shimano, ISIS from ...
Before I go and review a bottombracket, it might be worthwhile if I explained to everyone what exactly a bottombracket is. Let's start at the pedals. The pedals are attached to the cranks, the cranks are then attached to a spindle that goes through the bike frame. This spindle and the bearings that surround it form the bottombracket. As you may have guessed, it's not a very exciting thing to write about, so my apologies in advance for a very dull opinion.
There's two times that anyone is likely to come into contact with a bottombracket, if you're building up your bike from parts, or if there's a nasty grindy noise when you pedal and you need a new bottombracket. In this case, many people will take their bike to a shop to get it looked at as although changing a bottombracket is easy enough, it requires a few specialised ...
