Gladiator Shakes at 60+ MPH

[immaechu]

So I recently installed my 2.5" lift and 37s. Haven't really driven on the freeway. When I took the freeway, I noticed at 65-70 mph, it starts to shake pretty rough. The steering wheel shakes, i see the bed in the mirror and its shaking. I don't think its "death wobble" Cause I can drive on normal streets and brake no problem.

I thought maybe it could be a tire psi issue so I deflated to 32psi. Maybe still too high? And is it cold 32psi or when its hot 32psi. Anyways, I went back on the freeway at higher speeds and still had the problem. I checked all the bolts, just in case I missed something, but they were all tight.

I'll be going in for an alignment and tire rebalance. Maybe that could be the issue?

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[Renegade]

Tires out of balance.

 

[ShadowsPapa]

Tires out of balance.

Correct. This is a tire issue, NOT an inflation issue. People get hung up on inflation.
Either out of balance, a weight came off because it hit the caliper (seen that happen on a couple of 'em) or a wheel even not true.
Of course, 37's will be harder to balance well - and depending on what else was done, we introduce possible scrub radius issues.

 

[Renegade]

I see you’re running 37” Nexen MTs, and Black Rhino wheels. That’s a pretty heavy setup, and will be difficult to balance. If they do a static balance (single point for weights) and not a dynamic balance (inner and outer weight correction), you will probably still have a shimmy, even if they do get them to balance pretty well. It also looks like your wheels are negative offset. Did they put any stick-on weights on the front side of the wheel?

 

[ShadowsPapa]

I see you’re running 37” Nexen MTs, and Black Rhino wheels. That’s a pretty heavy setup, and will be difficult to balance. If they do a static balance (single point for weights) and not a dynamic balance (inner and outer weight correction), you will probably still have a shimmy, even if they do get them to balance pretty well. It also looks like your wheels are negative offset.

That last part - no one should expect them to be great on the highway. Looks nice but it's way outside of the geometry for behaving well. That scrub radius has got to be crazy.
And those heavy wide tires - a dynamic balance is an absolute must, even road-force balancing.

 

[Renegade]

Those tires are load F? If so, they have to be stiff and heavy. Here is a graphic explaining static vs. dynamic balancing weight placement so you can assess what you have.

 

[PDiddy]

Those tires are load F? If so, they have to be stiff and heavy. Here is a graphic explaining static vs. dynamic balancing weight placement so you can assess what you have.

I learned something today. Good to know.

 

[Caraholic]

Correct sounds classically similar to wheel and or tire balance problems

 

[immaechu]

Correct. This is a tire issue, NOT an inflation issue. People get hung up on inflation.
Either out of balance, a weight came off because it hit the caliper (seen that happen on a couple of 'em) or a wheel even not true.
Of course, 37's will be harder to balance well - and depending on what else was done, we introduce possible scrub radius issues.

What should they be inflated to?

 

[DirtySaylor]

So I recently installed my 2.5" lift and 37s. Haven't really driven on the freeway. When I took the freeway, I noticed at 65-70 mph, it starts to shake pretty rough. The steering wheel shakes, i see the bed in the mirror and its shaking. I don't think its "death wobble" Cause I can drive on normal streets and brake no problem.

I thought maybe it could be a tire psi issue so I deflated to 32psi. Maybe still too high? And is it cold 32psi or when its hot 32psi. Anyways, I went back on the freeway at higher speeds and still had the problem. I checked all the bolts, just in case I missed something, but they were all tight.

I'll be going in for an alignment and tire rebalance. Maybe that could be the issue?

I was told that it's a tire issue. Was told to switch from Thunderer MT's to Toyo or Nitto Grapplers. Ordered them, will let you know how it goes.

As an aside, I had the alignment checked and also installed a synergy trackbar. If switching out the tires doesn't work, i'm going to try to get the dealership to change out the steering box.

 

[Mjolnir]

What should they be inflated to?

There is no answer for this.

Do the chalk test, that is the only way to figure out where YOU should be

 

[Jeeperjamie]

I doubt it's the steering box. If it wasn't doing it before you installed the lift and tires then I'm pretty sure it's the tires being out balance, that sounds more like what's going on with it.

 

[ShadowsPapa]

What should they be inflated to?

I always start with the tire MAKER recommendations for the weight they support.
Adjust from there - yeah, the chalk test will narrow things down for rigid tires like that.
You can look it up - there's info everywhere on that method.
The idea is to distribute the load across the tire face EVENLY, not in the middle, not on the edges. They use chalk to indicate where the tire is making contact with the pavement.
Too low and you flex the sidewalls, over-heat the tires, wear the edges and have handling issues among other thing. Too high and you wear the middle, have handling troubles, it can want to wander, among other things, and your traction will suck.

For me it's never worked quite like "intended" - my very best, most even wear, has been following the tire makers info and my experience - and gut.
I've never had a tire wear unevenly due to inflation - but I've changed a lot of tires for others who have. It's a serious issue.
BIG tires on a light truck you aren't going to want to be where the shops want to run these at.
They had mine up at 41 - yikes!
At least the dealer who did the tire rotation last time when I had the Falken A/Ts on had the pressure down where it should be.

 

[KHam]

Definitely your tires are out of balance. Try find some place that handles a lot of big or offroad tires. I have found that some places that sell a lot of car tires lack the ability, experience, or maybe even equipment to balance really big tires.

And for the record, once you experience "death wobble", you will probably never forget it or mistake it for any other shimmy or vibration. A lot of people lose control of their vehicle when death wobble kicks in. It is a violent shaking that makes you think your vehicle is coming apart.

As a side note, I have had some decent luck with Dyna Beads from Innovativebalancing on big knobby tires that were stubborn to balance. They use them a lot on Semi tires that are always on the road as they keep the tires in balance at all times at highway speeds. If you have trouble keeping the weights attached it's an option.

 

[Schreconjeep]

OK, I'm having the same issue. I have a 1.5" coild spacer up front and 3/4" in rear, the rest of suspension is stock. I have 37x13.5x17 cooper STT Pros and Dirty Life DT-2 wheels 17x9 -12offset.

It definitely feels like a balancing issue but here's the thing, it has balancing beads. I thought that was supposed to balance dynamically all the time and be the best option for bigger tires????

I took them off and put hub-centric rings on to be certain they were seated right. It helped but it is definitely still there. Not sure where to go from here.

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