# Harmonic Bounce



## Barefootindad (Aug 15, 2012)

I have a 2009 Kia Borrego v-8 towing a 2012 230 rs. When on asphalt it's smooth as silk . On some concrete interstates I get a harmonic bouncing after 45 mph.
Anyone have any solutions or reasons for this?


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## CamperAndy (Aug 26, 2004)

The reason for the bounce or porpoising is due to the road expansion joint spacing and the wheel base and trailer combination. Contributing factors are the weight distribution bar set up, trailer/truck loading, truck tires and truck suspension.

Since you can not change the road and not likely to change the truck or trailer then you need to look at the contributing factors.

Tires - should be LT and not P rated. I have no idea what is on the KIA but I would bet they are P. These have much softer side walls which make for a smooth ride but are not good for towing.

Loading - make sure you have between 10 and 15% of the trailer weight forward on the tongue of the trailer.

Truck suspension - Most likely not really optimized for towing, you will need more aggressive shocks to dampen the bounce.

Weight distribution bars - make sure they are set correctly.


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## NDKoze (Jan 5, 2011)

A quick Bing search pulled up an Edmonds review of the 2009 Borrengo that states:



> Like many body-on-frame SUVs, there is a disconnected feeling from the road, but this seems particularly true in the Borrego's case. We assume two factors are to blame here. The rubber mounts between the body and frame, while they help absorb some shock and keep the vehicle quiet, contribute to a somewhat sloppy feel when going over bumps and potholes. Secondly, the suspension calibrations obviously have an even greater effect on ride quality.


So, outside of the things that CamperAndy pointed out, this may be something you have to learn to live with until a new TV is a possibility.

Hopefully this won't reduce the enjoyment of your new camper.

Good luck and happy camping!


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## muddy tires (Jun 22, 2007)

My friend finds the same thing with his Tundra and Nitrous toyhauler at certain speeds. He finds that accelerating or decelerating will make a big difference.


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## Insomniak (Jul 7, 2006)

The Tundra is notorious for bouncing on concrete freeways with big expansion joints. Mine hopped all over the place whether I was towing or not. My Ram truck rides like a Mercedes compared to my old Tundra.


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## Lmbevard (Mar 18, 2006)

I use to have the truck/camper bounce so much I couldn't go over 35 mph on a 12 mile section of road just north of us when I had the regular cab Dodge 3500 pulling my 5th wheel. We would end up going 6 miles out of our way to avoid that road. Bought a F250 crew cab and because of the longer wheel base of the truck, I hardly get any bounce at all on the same road. I'm not sure if there would be any way to change the length of the hitch enough to keep the wheels of the truck from dropping at the same time as the wheels of the trailer. All I know is that our poor cat sure is happier in the Ford than in the Dodge because of it.


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