>>1486883THICC is what it looks like
also they have cantilever brake bosses
some older bikes use brake pivot bolts instead but by the 90s that was dead aside from cheep bikes
>Is 26" standard for 90s MTB?for most bikes yes
with tire thickness between 1.75 (47-559) and 2.1 (54-559) maybe you can go thicker but you have to check the clearance of your frame and brakes first
650B (40-584) is a near equivalent to 26 inch rims in purpose
the french system of tires is weird (dont even try to understand it)
all of the different thickness of tires have the same outer circumference
as the tire gets thicker the rim diameter decreases
there are four grades of thick
A
B
C - very often incorrectly labeled
D