Stopping rear end sway under hard acceleration

[Gryphon313]

I lowered the tire pressure down to 36 psi...although a little better/more stable up to 100mph once I reach 100 it starts to sway again so there was no point in going faster than that.

Maybe I should ask what everyone has their pressure set at in their tires?? Those that are supercharged without towing or a load in the back

What‘a the speed rating of the tires you’re running? Assuming they are 35x12.50-17’s, it’s usually 99mph. That has to be playing a big part in the loss of stability at speed. May just be outside the design parameters of a few things once you hit triple digits.

 

[Xlr8tin]

Just so I understand what's going on with your truck,
are you getting the death wobble or is the back just swaying left to right?
And another question, is the front of your truck higher in the front than the back?

The death wobble is usually caused by,
bad tires, bent rims, incorrect alignment, bad shocks, trucks ride geometry is out of specs.
I know you said you replaced the shocks, but you may have received a bad one or two.

I run 38 psi. in the front and 34 psi. in the rear.

No, just the rear swaying when I accelerate quickly around 100mph. No death wobble.

I set the front shocks to mid perch to try to level.

OK so more in the front. I can try that next.

 

[Xlr8tin]

What‘a the speed rating of the tires you’re running? Assuming they are 35x12.50-17’s, it’s usually 99mph. That has to be playing a big part in the loss of stability at speed. May just be outside the design parameters of a few things once you hit triple digits.

Yea right around 100. They are stock size... 315 70 17. I can't find a tire with a higher rating and these tires are hybrid. I wanted something more highway with occasional off road for dirt and loose gravel. I'm open to suggestions though

 

[MTF]

I personally wouldn't use any other tire than the OEM, BFG KO2 Class E with a speed rating of S (112 mph.)
I do 130 to 135 quite often, for 13 years never had an issue.
Granted I'm not doing that for more than a few miles at a time.
And I did do 145 once and when I felt that I had no steering because the front tires left the ground,
I won't do that again. LOL

 

[Xlr8tin]

I personally wouldn't use any other tire than the OEM, BFG KO2 Class E with a speed rating of S (112 mph.)
I do 130 to 135 quite often, for 13 years never had an issue.
Granted I'm not doing that for more than a few miles at a time.
And I did do 145 once and when I felt that I had no steering because the front tires left the ground,
I won't do that again. LOL

If I could get the KO2s to last longer than half worn in the rain I would keep buying them, but diving safely in the rain at low speeds is more important to me than a few seconds once in a while at high speed. There has to be another tire. If not, than I need a better alternative. I've been searching for a lighter tire with a stiffer sidewall and hope this is good enough.

In a couple raptor groups people love the Falken wild peaks, but they are heavier that what I already have.

 

[MTF]

Have you been buying the Class E or the Class C
The Class C do wear much faster than the E.

Plus when you air down they will last longer and have a little better traction in the rain.
It's a trade off with tires, longer lasting means less traction in the rain and dry and vice versa.
When it rains out and I need to get going, I always use 4x4 Hi, you kind of need it to with the Whipple.
I only have 38,000 miles on my 13 year old truck and I'm on my second set.
The first set started getting dry rot and basically turned into plastic from age. LOL

 

[Xlr8tin]

Have you been buying the Class E or the Class C
The Class C do wear much faster than the E.

Plus when you air down they will last longer and have a little better traction in the rain.
It's a trade off with tires, longer lasting means less traction in the rain and dry and vice versa.
When it rains out and I need to get going, I always use 4x4 Hi, you kind of need it to with the Whipple.
I only have 38,000 miles on my 13 year old truck and I'm on my second set.
The first set started getting dry rot and basically turned into plastic from age. LOL

To the best of my knowledge they have all been E. I've had them on at least 3 trucks. This one had them and they were already half worn when I got the truck. When it rains here in Texas all the oils come out within the first few minutes and are like driving on ice. I've lived in many states and this one is the worst I've been on when it first starts raining. My ridge grapplers are fantastic, but they are still heavy which I think are around the same weight as the KO2s I believe. I may do a search on a higher speed rating and see what I come up with

 

[Xlr8tin]

I was wrong... KO2s are pretty light

 

[Xlr8tin]

Update: so I just got the truck back from the tune shop. I've been having issues since I bought the truck. The tuner said as soon as you were on the gas the truck went into boost so it made for a horrible shift experience. On the way home and on the interstate. I did one quick run up to 120 mph. I checked the tire pressure and they filled them back up to over 46-48psi after I had it at 34. That's why I only did one quick pull because I wasn't expecting much... Welp it ran flawlessly without swaying, I stopped at 120...wth

 

[TwizzleStix]

Sounds like they dialed back the onset of peak torque. Actually moving it up into the higher revs. That’s a good thing.