strike angle of a 26-inch wheel and a 29-inch wheel
(over the wooden block) is only about 5 percent, but
the cumulative effect of rolling up and over a 5-percent
steeper angle thousands of times a mile adds up quickly. The larger-diameter 29-inch wheel has noticeably
less rolling resistance.
Another benefit of a larger-diameter wheel is the
relationship between the bottom bracket center and the
wheel axles. A lower bottom bracket lowers the center
of gravity, and gives the chassis a more stable feel while
cornering. The bottom bracket heights of 26-, 27.5- and
29-inch designs are about the same, but a closer look
reveals a secret that might explain the highly lauded
cornering ability of 29-inch chassis. At 12. 5 inches, the
bottom bracket center is only a half inch lower than
the axles of a 26-inch bike, but the bottom bracket is 2
inches below the wheel axles of a 29er. Weighting the
pedals of a 29er puts much of the rider's weight well
below the axles, which has a profound stabilizing
effect.
26 VS. 27. 5 VS. 29
Jamis Bikes covers their bases by offering steel-framed hardtails in the three wheel size formats. When
they offered us three similarly priced bikes to try back
to back, we jumped at the chance for the ultimate
demo ride. You can argue with hype, crunch all the
numbers, and show up with years of bias, but when
you ride bikes back to back, things become clear very
quickly.
Wheel to wheel: When you ride bikes back to back, things
become clear very quickly. The wrecking crew didn’t have a
vested interest in any of the wheel sizes; the results came
from our rides.
Rough road: The
26er poised the
biggest challenge
for clearing
ultra-rocky terrain
(up or down).
The 27.5er
benefited from a
15-millimeter
front axle, but
more was going
on. The larger
wheels didn’t fall
between the
cracks. The 29er
inspired the most
confidence in
these conditions.
26”
29”
27. 5”
