In these photos I have tried to show the widths and diameters comparison of three different wheel sizes. On the left a 29er x2.1, then the 29er Plus 3" and finally the 26" x4" Fat bike tyre. As you can see the outer diameter of the 29er and the 26" Fat bike are pretty similar and the 29er Plus is far bigger. The 29er Plus is about twice as wide as the 29er, I put this down mainly to the wider rim width on the 29er plus (49mm)
HAND BUILT TITANIUM FRAMES.