Being both a mechanical and structural engineer, I would assume the reason the bike rack is rated for a B and not a C is that it is not designed for the impact force generated by the bikes when they move due to road conditions. The longer the distance from the rear axle to the bike rack, the more impact force (level arm) the bikes will exert on both the bike rack and hitch. (Think about using a cheater bar on a wrench to turn a stuck bolt.) C's tend to have longer wheel base and longer overhang from the rear axle to the hitch. The lighter e-bike rack MIGHT work on a short C that has a similar wheelbase and overhang as a B, but I would inspect it on a regular basis if you get it. Like the previous post, I have the Hollywood RV Rider. it is designed to be mounted on the back of a fifth-wheel vehicle and other types of rvs, and it has been on several long trips with no issues. Before getting this rack, I used a different rack not rated for RV for a couple of short trips and did notice the rack starting to bend. I hope this helps.