Sorry about the long description. I don’t know how to explain this shorter.
So I changed the crankset to my old bike. Old and new one that I found from a local store had a quite different chain line so I opted for a longer bottom bracket axle. Old crank set is Sr Suntour Pff and the new one is Shimano FC-TY501. Both have 48/38/28T. Old bottom bearing was 110mm (B098 Slovakia Kinex Vb 110 JIS) new one (Shimano BB-UN300 BSA) 127.5/68 mm. Drive side was perfect fit but the left side cup was incredibly tight fit. I don’t think I can get it out in one piece if I ever want to change it again.
It works just fine but it looks a bit odd because the left side also has a flange? When I bought the bottom bearing cartridge I noticed someone had already opened the package and another crank bolt was missing. I didn’t need it because the new crankset had correct ones. It was off course the last one on the shelf so I bought it. Did someone change the left cup or did I bought the wrong part or what might of happened? Old one was JIS (shouldn’t make that much of a difference with the new crank set?) and the new one is not. Sorry about the poor pictures.
by Infinite_Trick6895
6 Comments
JIS and ISO definitely makes a huge difference.
What make and model of bike is this on? Generally whatever BB standard comes off your bike is what goes back on.
Off topic, but is that a Bessler 23C in the background? You have your bike shop in your darkroom? Or vice-versa.
Ok so JIS means Japanese Industrial Standard which is essentially a square taper BB. They do come in different spindle lengths. Measure the spindle length of old BB and then order a new one and you should be set. They are very inexpensive.
68 mm is the width of the shell so make sure new BB is also a 68 because they also come in 73.
Being very tight is not a problem. It shouldn’t just thread in, it takes some oomph. It’s held in by the tightness. The BB probably also had some Locktite-type stuff on the threads that makes it stickier. I think what you’ve experienced is normal.