The rating on the tire ( C, D, E, ) is NOT the LOAD rating. The tire will have a load rating say 1900lbs to 3900lbs. The letter rating is the strength of the sidewall of the tire. Lets say your tire is rated at 2000lbs and you are running at 1500lbs, tire can handle that, no problem. Now lets say you hit a pot hole going 50mph, the impact on the tire sidewall will be greater than 2000lbs. Thats where the Letter rating comes in, sidewall impact strength. E is stronger than D and D is stronger than C ....... Now C will be a softest ride on the road and E will be the firmest ride. I have had all ratings on my Jeep, it's a personal preference what you like. To me No big deal.