alaska

i was putting my bike together today and i came into a problem with my sugino 75 bottom bracket. the cranks i was trying to use would touch the shell before tightening completely. so i decide to simply flip the bb around. both sides end up loosening in the same direction, toward the back or leftside counter-clockwise and rightside clockwise. this just struck me as odd until i tried to put it in the other direction and neither side was threaded correctly. so i try to stick in a shimano un53 bb and the leftside goes on fine but the right side is threaded the opposite way. has anyone bought a bike with a sugino 75 bb and tried to switch it out? all the bikes i can find with a 75 bb have the matching sugino 75 cranks. are these the only ones that work with the bb? what the hell is wrong with my bike?

fixedpip

I have no idea about your crank issue, thats weird because I thought JIS bbs had a wider taper than ISO BBs. Suginos, reputedly have a slightly modified JIS taper but not enough to make a difference IMHO.

I can't see why you're cranks are bottoming out unless they have some design issues that mean they can't sit close enough to really get pressed onto the tapers.

What crank are you trying to use?

I'm a little confused as to how you can flip the BB here. The Sugino 75 is only available as in English threading adjustable style BB: the fixed cup has a left hand threading, the adjustable cup has a right hand threading (counter-clockwise to loosen) - think thats right.

So if you flipped the axle thats fine. However, if you put the adjustable cup on the fixed side its quite likely that you could have damaged the threads. So check:

You haven't cross-threaded the BB shell by flipping the BB
You have an english threaded replacement BB
The threads on both the shell and cups are cleaned and lightly greased.

alaska

ah, the whole flipping idea was just for testing, it didn't mess anything up.

i was trying to use sugino maxy cranks that are intended for multiple gears. the major problem is that where the square taper of the axle is sits behind the recess of the the shell. thus, the cranks must extend outwards to fit properly, or so it seems.

i really just want to know why the shimano bb would thread on one side but not the other. italian/english problem or is that only change thread spacing?

Aeroplane

Definitely Italian or French/English problem. Check the SB:

https://www.sheldonbrown.com/gloss_bo-z.html

Read the Bottom Bracket section.