Frame Stiffing to reduce Porpoising?
Got a question for you seasoned drivers with older rigs. I have a 1999 F350 Dually Quad Cab Long Bed. I've been driving it for thousands of miles and for the most part, it's been fine. However, while driving on rougher roads, I do get a porpoising effect happening. I can look in my rear view mirror and see the frame flexing at least an inch or two.
My camper is the Bigfoot 2500 and with everything loaded up is probably in the 4500lb to 5000lb range. According to the sticker on the camper the center of gravity is almost exactly over the rear wheels. Now the center of gravity does change with water in the tank as the fresh tank is in the front of the camper which puts it at the front of the bed.
The porpoising isn't a "problem" in the since that I am concerned about it causing damage. I'm well within the carrying capacity of the truck. That being said, it is an annoyance for comfort and drivability. I have already replaced the shocks on the truck and that has helped somewhat. I am also looking and seeing that I probably could move the camper another inch or two forward when I load it. I don't think this will make much of a difference though.
So, my next thought was to look at having my frame reinforced. I know there are all sorts of complications when going this route though. Ford does fully boxed frames for a reason because it gives so much more rigidity. I no there is at least one person that has done this on their 7.3 from a posting on the Ford forums. This is obviously a huge expense and extreme measure.
Has anyone else gone through this or found a way to handle excessive porpoising on older C channel frame trucks?
-------------------------Update-------------------------------
Because several people have focused in on the camper weight and that has taken this question off from what I asked, I am adding this here for anyone new reading this thread that thinks to jump in and comment about weight. Later in this discussion thread I post a response where I provide the factory weight as measured was 2733lbs and with AC and Genset just under 3000lbs. That is way lower than the 4500lb to 5000lb I stated in my original question above. I have also weighed my truck and it is 7600lbs and so the payload capacity is 3600lbs and the axle capacity of 4870lbs. I am not grossly overweight as some thought based off my original and inaccurate guesstimate in my question above.
Secondly, I also overstated the amount of "porpoising". It is not excessive in that I am concerned about the truck breaking in half. What I have observed others mainly in the overhead movement of the camper above the driver seems to be common with others.
Finally, my question in this thread is asking if someone has ever added additional bracing to the frame of the truck. I'm asking the question if this has been done before. The consensus in this thread is that it is very rare and it is very complicated to do and probably not worth the effort.
My camper is the Bigfoot 2500 and with everything loaded up is probably in the 4500lb to 5000lb range. According to the sticker on the camper the center of gravity is almost exactly over the rear wheels. Now the center of gravity does change with water in the tank as the fresh tank is in the front of the camper which puts it at the front of the bed.
The porpoising isn't a "problem" in the since that I am concerned about it causing damage. I'm well within the carrying capacity of the truck. That being said, it is an annoyance for comfort and drivability. I have already replaced the shocks on the truck and that has helped somewhat. I am also looking and seeing that I probably could move the camper another inch or two forward when I load it. I don't think this will make much of a difference though.
So, my next thought was to look at having my frame reinforced. I know there are all sorts of complications when going this route though. Ford does fully boxed frames for a reason because it gives so much more rigidity. I no there is at least one person that has done this on their 7.3 from a posting on the Ford forums. This is obviously a huge expense and extreme measure.
Has anyone else gone through this or found a way to handle excessive porpoising on older C channel frame trucks?
-------------------------Update-------------------------------
Because several people have focused in on the camper weight and that has taken this question off from what I asked, I am adding this here for anyone new reading this thread that thinks to jump in and comment about weight. Later in this discussion thread I post a response where I provide the factory weight as measured was 2733lbs and with AC and Genset just under 3000lbs. That is way lower than the 4500lb to 5000lb I stated in my original question above. I have also weighed my truck and it is 7600lbs and so the payload capacity is 3600lbs and the axle capacity of 4870lbs. I am not grossly overweight as some thought based off my original and inaccurate guesstimate in my question above.
Secondly, I also overstated the amount of "porpoising". It is not excessive in that I am concerned about the truck breaking in half. What I have observed others mainly in the overhead movement of the camper above the driver seems to be common with others.
Finally, my question in this thread is asking if someone has ever added additional bracing to the frame of the truck. I'm asking the question if this has been done before. The consensus in this thread is that it is very rare and it is very complicated to do and probably not worth the effort.
