Fred:
The Ram I am looking at will be a Mega Cab and the nose cone on the Heartland allows for I think an 80 degree turn. I was looking at ordering the Ram 5th wheel set up with the Truck and that is when they stated the measurements required without a slider. So I am not sure if you would really need the slider or not, but after spending that kind of money on a new Truck, taking a chance could be even more costly down the road. Perhaps someone with a 2015 short bed in use could chime in...