What to blame for harsh freeway ride?

Here's my issue, the truck rides ok around town. Obviously firm because of my setup, but not unexpectedly harsh. However, on concrete paved freeways (with the stupid seams every 10 feet) at 70ish mph the truck bounces horribly. It's extremely uncomfortable and becomes unbearable on long trips. I've got Icon coilovers (set to factory setting about 2" of lift), Icon progressive AAL, Icon VS 2.0 rear shocks (non-resi), and LT285/75r16 BFG ATs (normally in the 33-35 psi range). So my question is, what is causing the crazy bouncing? I'm considering downsizing to a P metric tire 265/75r16 or maybe my rear setup is to blame? I feel like maybe my rear shocks aren't valved properly for the stiffness of the 3 leaf AAL, though my whole setup is from Icon so I assumed they were designed to work together. Another reason I suspect my rear end isn't working together properly is while towing the boat (16' bayliner) the rear end and trailer bounces a lot. Any input would be greatly appreciated!

 

The 3 leaf AAL isn't stiff.

I'm going with your tires are too stiff, by design (I assume they're E rated).

 

+1 for tires. I have that same exact setup with c rated 265/70/17 and I don't have those issues, although I don't like the way the rear shocks are valved. I'd hate to say it, but I think the 5100's on my old truck handled better in the rear with the Icon AAL. I'll never repeat that though

 

Yea I figured most would condemn the tires, and i'm seriously considering downsizing back to a P tire. I'd like to hear from @icon_rep about the valving though of the non-resevoir rear shocks for 1st gens. I've noticed in the "stage" kits, a stage 1 comes with the non-resi shocks and no AAL, and the stage 2 comes with the AAL and shocks with resevoirs. Are the resi vs non-resi shocks valved differently to run with or without the AAL, or are they both basically the same? I bought my parts individually, not as a kit. Should I have gone with the resi type rear shocks?

 

Its not the aal..... its waaaaay plush imho, thats the whole point.

 

I would also check the condition of the seals on your suspension... I have e rated tires at the same pressure, the exact same rear shocks AND a wheelers HD leaf pack (stiff) and I haven't been too bothered by anything at high speed. Perhaps it's time for a suspension service? Do you carry any weight regularly?

 

It's pretty rare that I carry a lot of weight, occasionally I'll load up a couple motorcycles or tow the boat, but thats pretty much it nothing serious. The coilovers only have 25k miles on them and my rear setup has only 15k... cant imagine needing a rebuild already.

 

Is the bouncing more noticeable in the front or the rear?

 

Sometimes product sits on the shelf for an extended period of time before its purchased and put to use. Seals dry up and become dysfunctional. I'm not car mechanic but that's something I used to see in mountain bike suspension all the time! It's worth having a look, anyhow!

 

This is well outside my range of experience, so be warned I'm probably talking out of my ass, but I'd expect a stiffer tire to produce bumps and thuds rather than "bounce".

Can you describe in a little more detail what you are feeling? Is it a sharp thud as you go over the slab seams on the highway without much larger body motion? Or are you actually "bouncing" in the sense of larger body motion like rocking as the suspension gets hit with bumps from the slab seams?

If it is the former it sounds like tires and an easy way to investigate that would be to run *briefly* along a section of road that causes the problem at significantly lower tire pressure. If it is the later then it sure sounds like the suspension is under damped and a failed suspension component, especially a shock, could be the cause. Sure your shocks *should* be fine given you don't have that many miles on them, but certainly they could leak or have been charged to the wrong pressure or who knows what else.

Good luck!

 

Just wondering if you figured this out OP. I HAVE THE EXACT SAME PROBLEM, AS DESCRIBED BY YOUR ORIGINAL POST!! this is on a 2016 TRD Off Road.

just posted the following today.

https://www.tacomaworld.com/threads/icon-suspension-very-rough-ride.454618/