27.5+ vs 29+ tire mountain bike tires
Trek suspension engineer, Ted Alsop, puts it this way, "27.5+, ideally, has the diameter of a 29×2.3 tire, but to get there, you have to give it a really tall sidewall. The bead-to-bead measurement-that's the actual width of the tire if you pressed it flat and measured from one bead to the other-is about 15 millimeters wider than a 29+ tire. Relative to the rim, the 27.5+ tire is actually taller than the 29+ tire, which is why we've found that the 27.5+ tires that we've ridden have a lot more of an un-damped, fatbike tire bounce to them and don't corner as well at lower pressures. The 29+ tire, which is actually a lower profile, shorter sidewall tire, has less of that uncontrolled bounce to it."
