100% stock - VERY rough ride

[Old462]

OK I bought my truck a couple of weeks ago, and just yesterday took it on an extended trip down the interstate for the first time. The truck is a 2007 F-350 CC LB King Ranch SRW, 83K miles, 100% stock w/Michelin LTX A/T2s all around. Front tires at 55 psi, rears at 45. While driving at 75 mph (speed limit), the truck was almost bouncing, front to back, not side-to-side. Felt like I was driving on a washboard gravel road. This condition got a little better by switching lanes, and became tolerable by slowing down to almost 60mph, but at that speed I'm getting run over by everyone else on the road. Interstate surface was concrete. It later switched to an asphalt-type surface and no bouncing whatsoever. Now I realize that this is a big, heavy truck, and it's going to ride as such, but this seemed to be over the top as far as rough rides are concerned. Is this something that anyone else has encountered? I've poured over almost all of the suspension section of this forum, and I'm pretty sure I'm not experiencing the "death wobble" that many others have, and haven't found any threads with a similar issue. Might an adjustment in air pressure help with this? Go to 65/50 front/rear as suggested in another thread? And I haven't ruled out new shocks, either. Going to price some of those in the morning. Any words, advice, and/or similiar experience w/fix would be appreciated. Thanks.

[dieselmast]

Have you comsidered the idea that since you got zero bouncing once you went to asphalt, that it was the road? I know in SoCal, the concrete roads are horrible and as I used to do road work for a living, I can tell you that concrete roads are NEVER smooth. Just the way they are poured and the way that concrete shrinks and swells. Have to be poured in sections and that is why you will get that front to back bounce on most of them. Just a thought since you said you had no problem on asphalt.

[Old462]

Yes, I'm well aware that it was mostly caused by the expansion joints in the construction of the road. However, I've driven this particular stretch of road hundreds of times and never had a vehicle ride this badly. Also, while bouncing on this stretch of road (headlight beams bouncing rapidly up and down in front of me) I was passed by another F-350 with what looked like a 4-6" lift, and it was riding smooth as could be - his headlight beams weren't bouncing up and down like mine were - in fact, not at all -plus he was going at least 5 mph faster. I'm wondering if some kind of shock upgrade from stock might improve the situation. Thanks for the insight.

[GoFastPadre]

I also have a stetch of road the causes a severe bounce if you ride in the right spot. I wonder about the tires and pressure as well. It would seem more pressure would cause more bounce and what load range are your tires? If they are D's 55 might be the max pressure for them.

[dereku]

tire pressure seems low. I run 65 in mine and it rides smooth.

[Mike Hickman]

re-balance ?

[Shockley6.0]

concrete on these trucks always do that. Other vehicle's might have been lighter. I know mine does everytime I go over concrete. Same with my 95'. Just seem's like if it aint broke dont fix it. Just think its the road.

[Old462]

Alright, thanks for the replies, y'all. I'll check my tires, up the pressure, and hit that road again. Might be due for new shocks anyway, I have no way of knowing how long these have been on the truck. Couldn't hurt anything but my wallet.

[Bad Night]

Yea , shocks are cheap , start there , that's what it sounds like it needs to me . 80 k if there original it prob. needs em anyway .

[scotty2280]

shouldn't the rears be a 80psi?