Joined: Jan 2008
Posts: 23,642
Likes: 1,106
From: Mans of NC & SW UT Desert
Bikes: 86 Katakura Silk, 87 Prologue X2, 88 Cimarron LE, 1975 Sekai 4000 Professional, 73 Paramount, plus more
2 inches is huge (5cm). But I find the chart above to be most useful for road/racing bikes. So you could be fine.
I use this chart all of the time, but its a starting point.