I have wheels with 285/70 -17 Nitto Terra Grappler tires and am having issues with the the rear suspension. When I go over bumps/potholes, there's enough mass in the wheels to cause the axle to momentarily shift out of it's normal position so that you can feel the back end move slightly to one side or the other - similar to axle tramp. I was wondering if anyone else has had a similar issue and what they may have done to stabilize the axle better. When I put the large wheels on, I was hoping the the offset shocks might hold the axle in place, but maybe I need a tougher shock. In the past I would have considered some stabilizer arms or additional shocks, but these solutions all require welding on extra mounts on both the axle and frame and I would prefer to get a quicker bolt-on solution (cold weather is coming and I loose my enthusiasm for fabrication).

 

sounds to me like you need a stabilizer bar... as to how you would mount it I haven't a clue.

maybe you could go pluck one from a Junkyard. With a drill bit and good measurments, it should be fairly minimal work, I think the hard part would be finding somthing to fit.

 

We have a stabilizer bar on the rear end I would start with checking that you indeed have one. I would also recommend you getting new rear shocks our stock ones suck. A lot of us have gone with Rancho or Monroe.

 

just my .02 but the monroe's with the coil springs on them have a great ride and really do make towing trailers more comfortable. They are a bit stiffer than the factor so they definitely should help.

 

lets be certain that when you guys say "stabilizer" you mean sway bar? we have a sway bar....we do not have a trac bar or pan hard bar.

those 2 bars prevent the axle from shifting side to side and rotating. although our leaf springs act as a pretty good trac bar and panhard, sometimes things come loose allowing the axle to shift around. ive got 33's and don't notice this problem so i would check all your hardware. if anything a simple tube welded to a plate with some u bolts and than attached to the front bolt of the leaf spring would eliminate any kind of axle movement forward and rear wards.

sway bars don't prevent axle movement. they just keep the axle and the frame from going separate ways.....

but if its the back end of the entire truck you feel hopping around than its probably just bad shocks mixed with the little weight pickups have in the back. and bigger tires tend to bounce over things especially when fully inflated.

 

I take it you are running the LT variant of the tire.

From Nitto Tires.
Size:LT285/70R17 E126R
Rim width: 7.5-(8.5)-9.0
Load: 3,750lbs. at 80 PSI

If you are dropping a wheel in a pot hole or hit a bump, and the truck wags it's tail a little. Check tire pressure. (More rubber between the rim and the road = possible wiggle) This can become more noticeable if running on a narrower 7.5 inch rim.

What pressure are you running at? 80psi would be a bit high for the light weight of the Dakota, 35psi too low. I would try 45-50psi and see if that corrects the problem.

[!!NOTE!!] If you have the P285/70R17 117S DO NOT! pt that much air in them. Those are only rated to 35psi.

 

This has happened 3 times, every time after I have tires put on the truck. The tire place inflates all the tires to 60 psi and then it bounces all over the road. After I take them down to 35 - 40 it rides much better and I still have even tire wear. 265/75/16 tires.

 

Thanks for all the tips folks, if we do have a dry weekend before the snow arrives, I'll lift the rear and check all the suspension again and I'll also try playing around with the tire pressures and maybe change to the Monroe shocks with the coil springs to stiffen things up. If this doesn't help, I'll have wait until wrenching season next year to fabricate some form of stabilization. I'd like to attach a camera & lighting arrangement of some sort to get an idea of what's actually happening with the axle after a bump (I thought of attaching my inspection camera but it doesn't record). Knowing what it's doing is always a good way to a good design.

When I last had the truck raised (when I was installing the lift kit), I checked everything around the rear suspension and it seemed pretty solid including the sway bar bushings. At this time I also installed new Monroe Sensa-track rear shocks, but I'm thinking that these might be too lightweight.