Originally Posted by
LesterOfPuppets
On MTBs, 2x is slightly easier to keep adjusted and affords more tire clearance. On many bikes, going bigger than 2.1 will result in the knobbies buzzing on the tail of the FD cage. Problem increased with 27.5 and 29" tires.
I'm trying to remember what the industry's motivation was at the time. I agree w/everything you say above about ease of adjustment and clearance. Wasn't there a market segment at the time that wasn't using the third ring much anyway? The all mountain segment? That's sort of what I recall, and I remember two rings and a bash guard being a common configuration for a while. And didn't XC racers hold on to that third ring a little while longer for the added top end?