I think you will be limited by your TV. I have a 2015 GMC Denali, SRW, Diesel 3/4 ton and a 35' 5er. So, look at your owners manual and determine your weight ratings. I wouldn't want anything bigger than what I have. Where I notice the difference with a SRW is dips in the road where the trailer tends to rock forward and backward. So, in general, I'm thinking less than 36' probably ok, 36-39 pushing it, greater than 40' need a DRW. Of course, everything depends on the weight ratings of your specific truck and trailer.