Class B motorhomes are much smaller than Class As and are, in fact, the smallest type of RVs (even though the "B” designation might make you think they're the middle option regarding size).

So-called "Class A" RVs are your tour high-zoot motorcoaches similar to a fancy tour bus. Your friend’s Mercedes Sprinter-based Winnebago Revel is a shining example of a "Class B" RV.