Now running 285/70/19.5 Toyo M608z tires, which are 35.5 inch, 16 ply tires. Yes, they are hard as plastic and yes, they are rough riders. They weigh 95 lbs each and the wheels add 67 more lbs. The problem I'm having, I'll call "dribble". At about 45 mph, the fronts will begin to bounce and that can continue for a while, but you can accelerate out of it. Usually around 70 mph or so, it will smooth out completely. The tires are well balanced, so that's not it. I'm wondering of heavier shocks could help by dampening the bounce. I put a Bilstein steering stabilizer on which may have helped some. I have new Monroe Reflexes now, but they seemed soft even before I got these tires. Any thoughts, other than, "those are big hard tires" I'm already aware of that.

 

Because there is no flex in those tires, you might need to run a dual shock up front or upgrade to a bilstein or Rancho 9000xl those are heavier duty shocks.

What pressure are you running in these and what made you switch over to the big rig rims?

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I'm at 75 psi now. They recommend not dropping below 65 psi as they may lose the bead. To avoid a long winded explanation, I wanted bigger tires, my truck had 16 x 7" wheels which you can't put a decent sized tire on unless you go way too wide. I couldn't find a hub centric wheel I liked. I heard about Rickson wheels, bought a set and put 80k mostly happy miles on them. These are the replacement tires. While these have fantastic traction, I ain't enjoying all the bouncing. Is this bounce what you would normally expect from big heavy tires?

 

Its the bounce that you would normally expect if your shocks were blown. And because the tires and rims are so heavy the monroes might have a severely shortened life span. Or just not enough dampening to stop the 140lbs from bouncing

Have you checked your steering linkage and ball joints? The heavy wheels can wreak havoc on your wearable parts.

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The ball joints are "showing signs of wear" but they (my mechanic) didn't feel that they were ready for replacement. The Monroes are new (<5k miles), but they seemed too weak from the start in my opinion. To clarify, this is not the slow bounce you get as your shocks weaken. This is a very rapid dribbling type bounce that shakes the steering wheel like an out of balance tire, but that has been ruled out.

 

Bump to see if any of the folks who were watching the (less than) Super Bowl have an opinion...

 

Have you had the tires "Road Force Balanced"? Just because a dynamic wheel balancer says it is balanced does not mean that it is balanced and true to the tire/wheel combo. I had a similar issue with a set of tires on my truck. I had them balanced at 3 different shops with dynamic balancers before having them 'matched' to the wheel(RFB). I had one wheel/tire combo that was waay out of match. What I can use to describe so you understand, is like having a high spot on the bead of the tire and seating to a high spot on the rim. The tire in dynamic rotation can appear balanced, but when the wheel/tire combo has weight on it and is rolling down the road, it will hop. Like having a tire out of round. I was told by the serviceman at the last shop this is more common with larger tires with more rubber to balance.

I spent alot of time and money going back and forth to the original shop that put the tires on and additional shops thinking that I had goons working on my tires. The original shop replaced a wheel from their damage and two tires. Still that did not resolve the issue. After having the RFB done, the truck rides smooth.

Not sure if this is the cause of your issue, but I hate chasing gremlins when it can be a easy fix. Hope this helps.

 

They mentioned that type of balancing when I first took it in. They took the tires off of the rims to get the balance beads out (didn't balance anything), so they could have done it. I'll have to check to see if they did.

 

The first time I had them balanced, the were done the "old fashioned way", tires on the truck, spun up to what looks like 100 mph and then weights added until the balance. It still bounced about the same then as now.

 

Where is the weight being stuck on during balancing? My local Discount Tire does Road Force balancing and the weight is put on along the inside edge of the spokes (nearly on the centerline of the wheel) with a couple of weights along the inner lip of the wheel. My tires are big and heavy and have none of the bounce you described. All my suspension components are pretty much new with the exception of ball joints (new springs, shocks, sway bar links, etc.). Another method that some of the off-road shops use on these bigger tires is the bead bags that they put inside the tire when mounting (can also be inserted through the valve stems). Once the vehicle is driven the bags break open and the beads dynamically balance the tires from that point on. I've never used them, and I've heard both good and bad from tire pros. You may also consider the possibility that you have a bad tire (manufacturing defect). Have you tried putting them on another vehicle to see how they ride?

 

is this the steering wooble in disquise? dual rancho horizontal stabilizers and complete all round replacement of verical shocks to rancho 9000's fixed mine.

 

I don't think so. Hitting a bump doesn't seem to set it off, and changing my single stabilizer to a Bilstein 5100 made little to no difference. Other than that, I can't say for sure.

 

I will say this, it's as consistent as sunrise that at about 45 mph the whole truck is shaking from it and that accelerating quickly will stop it immediately.

 

Might be worth rechecking the ball joints, sounds like a tight wobble which means what ever is moving isn't moving far. Ball joints can be checked by jacking front tire and push, pull the top of tire.

 

That's the next step after what I found out tonight fails. I went back to the last tire shop tonight just to see what they had to say. They said that, based on the speed at which it occurs, the think the tires are still acting out of balance. I plan to take it back there Saturday and let them try to do the "road force balance" on them. The tire man seems to think that RFB probably won't work on 19.5 wheels since the shape of the rim (how it's angled) won't allow it to "seat the same way every time." Not sure what he means by that, but Rickson sells there wheels with the tires installed and "match balanced". The first set I got from Rickson were well balanced, so I know it CAN be done. I'm just not sure the local guys can do it.