fishtailing

I have a 2020 offroad, DBLCB, short bed. The truck does have a snugtop topper, but for the first couple thousand miles, it did not, and that is when I first noticed the fish tailing. On washboards at low speeds, bumps on pavement at low and moderated speeds. Thought when the topper was added, the weight would settle the back end. My son has a 19' offroad DBLCB, no topper, and does not have this problem. Both trucks are bone stock. Anyone else have this problema?

 

Check tire pressures, just a few pounds can make a huge difference in unloaded pickups. Many shops prefer to fill them based on what they think rather than what they measure.

 

Check the tire pressure. Last time my truck was at the dealership, they had all 4 tires overfilled and the truck was noticeably more skittish over rough ground.

 

This.

The dealership ALWAYS overinflates my tires. Often times it'll be to 35 or 40 psi when recommended cold PSI is 30 according to my door sticker.

 

They are at 30.

 

Could be your rear shocks. They could be bad, or the valving on the stock shocks isn't up to the added weight. In either case they would be compressing harder/faster, but not able to rebound quickly enough. Which would cause a loss of traction/fishtailing coming off bumps.

 

Also. It's a pickup truck, which already has a horrendous weight balance and is geared a little more for torque and the front engine rear wheel drive layout, then Toyota goes and uses a fiber reinforced composite bed to further lighten the rear end.

The weight balance is absolutely garbage, through a little more weight in the rear and up high were it can get a tad of leverage over the suspension and you have a recipe for the ass wanting to lead the nose.

If you turn all the nannies off and keep your foot in it (when in doubt throttle out) it can be quite fun.

 

Sounds pretty normal for a pickup.
Every truck I've owned hopped around a bit on washboard and rough roads... Hell my Superduty with 4000lbs of tools and stuff in the back will still get squirrely on some of these oil field roads.

 

Have you driven your son’s truck on the same stretch of road for comparison or did you just ask him if he had experienced the same thing? This sort of thing can be very subjective.

 

Every truck does that on washboard to some extent. Weight does help but physics say that a solid rear axle and washboard road will cause the rear end to lose traction. Every truck I have ever had would do it at speed. If your truck does it... slow down. Or... speed up and have fun. Your call.

 

I own several 1 ton trucks for work, and nothing is a squirrely as this thing! Yes, I have taken my son's truck on the same roads to compare, his does great?

 

I don't know what else to say. Give me any unloaded truck with live rear axle and I can find a speed to make it happen. Much harder to do with independent rear suspension but possible. What happens is tires go slightly airborne for an instant. It is what it is.

 

Figured I would just check to see if anyone else is noticing a more than typical fishtailing like I am. Thanks for the help. I will just keep telling everyone to hang on.

 

Same shocks, same springs, same wheelbase, approximate same weight, approximate same age, same tires(?), same tire pressure(?). . I don’t have an explanation for you.

 

What's the mileage difference between your sons truck and yours?

 

Like said, tire pressure. These trucks are sensitive to the tire pressure, and it sounds like the op's are over inflated.

 

My '13 Sport did this, unless it was laden. My 20 Pro did it to a much lesser extent, and practically non-existent now with ~300lbs of overland crap bolted on.

 

THis. 40PSI youll be bouncing everywhere. I ahve my load E KO2s at 30psi

 

My 2020 was very stiff till broken in. I had to carry at least that much weight for around 5k miles till the suspension felt a lot better. Found out later during my 1st service. Dealers service manager said these trucks need at least 5k miles for the suspension to settle in and ride better.

 

Have you driven a 3rd gen?