Answer
The odometer will incorrectly calculate the traveled distance to be higher than it is.
Work Step by Step
Each time the wheel turns once, an odometer meant for 27-inch wheels will “think” that the bicycle moved a distance $\pi (27 inches)$.
However, if the odometer is moved to a bicycle with 24-inch wheels, each time the wheel turns once, the bicycle will only have traveled a distance of $\pi (24 inches)$.
In other words, the odometer will read a distance that is 12.5 percent too high, i.e., by a factor of $\frac{27}{24}$.