What can I do to get a smoother ride when towing?

[campertom]

I am towing a 34' trailer (2007 Crew Max SR5 w/tow package). Tongue weight is 1000lbs, front and rear axles are both well under max. GW is just under max. I use an Equilizer WDH, 1000lb bars. I have had no trouble with sway, and the ride is mostly comfortable. But, whenever I run into a rise or dip in the road, I get a bit of trampoline effect. The larger the bump, the larger the bounce. It is very unsettling, though never feeling at all like a loss in control. Looking in the rear view window, I see the trailer rocking front to back as it hits the bump, rocking two or three times after the bump, before settling down. In the truck, it is like being dropped onto a trampoline.

I'm thinking I should look into replacing my Tundra with a 3/4 ton truck, but before I go down that route, I wondered if there was anything that could be done with shocks, springs, tires, or anything else to lessen the bounce.

[bbarada]

I recommend the Bilstein 5100 shocks. The fronts are adjustable, and I set them on the middle setting. The rears aren't adjustable. Really dampens out the pogo effect but doesn't make the ride any rougher.

[Jowett Engineering]

I'll second the shock change. The wallow you get is mostly a result of the lack of rebound dampening in the rear shocks.

We dyno'd the stock Tundra TRD Bilsteins and found them to quite (overly IMO) stiff in compression, and decent on rebound. I'm guessing you don't have the TRD package?

[Art64]

Rancho 9000XL adjustables have excellent rebound control. I have Firestone airbags and when the truck is not loaded, it gets a lot of kick-ups on dips and bumps. Tried Bilstein HD's but not enough rebound damping. Rides smooth, until you hit a dip, then the rear is airborne!

[mxsjw]

Are you sure it's shock re-bound, or could it be "porpoising"?
You may need to re-set up your WD hitch, check the instructions that came with the hitch, or search the towing section of Tundra Solutions for advice.

Thread moving to towing.

[2007dctundra4x4]

firestone ride rite airbags are by far the best purchase i have made as far as towing is concerned...i tow a 32 foot travel trailer with a front kitchen so the tongue weight is also 1000+, and i also have the topper which isn't very light either, rear end does not drop at all

[TundraBay]

Originally Posted by Jowett Engineering

I'll second the shock change. The wallow you get is mostly a result of the lack of rebound dampening in the rear shocks.

We dyno'd the stock Tundra TRD Bilsteins and found them to quite (overly IMO) stiff in compression, and decent on rebound. I'm guessing you don't have the TRD package?

If he's got the SR5, does that imply TRD, or is only the Limited which pretty much automatically comes with TRD?

Anyway the other thought is maybe the Equalizer is set too high? That will tend to un-weight the rear end (have you weighed your rig?) and any upwards force for example from a bump will result in the rear end bouncing against the trailer weight. I'd definitely try a few different settings before totally giving up.

3/4 ton ride in my own experience was worse, whether loaded or empty.

[tomhole]

I second the recommendation to check everything else first. Rear truck tires should be at max pressure. If you still have the P rated tires, replace them with LT tires. Make sure the trailer tires are at max pressure as well.

Next up is the WDH. How have you determined it is set up properly? Weights are the best, but measuring the wheel well drop before and after hitching up is good as well.

If all that is done, then I would add airbags. Or the Rancho adjustable shocks. 1,000 lbs is a lot of hitch weight well behind the axles, so they may need some help.

Tom

[campertom]

The weight distribution seems pretty good - both from the scales and the measured height. I haven't heard the term 'porpoising' before, and don't follow what the difference is between that and 'bounce'. My truck does not have the TRD package - standard suspension and springs for the tow package, whatever those are. I did add air lifts, and keep them at 20lbs while towing. I tried higher pressures, but that made the truck bounce (as opposed the the trailer bounce) worse.

So, recheck weights and WDH, make sure tire pressure on the trailer and truck are max, Rancho adjustable shocks, LT tires ... anything else?

[campertom]

I just ran into this definition of porpoising on an Airstream forum - suggesting that shocks are the right solution for that as well

Porpoising is a problem on concrete roads when the expansion joints are just far enough apart compared to your wheelbase and speed. The bounce from the joints is just right to reinforce the rig bounce as it goes down the road. Sometimes this porpoising can be reduced by removing spring bar tension on the hitch which allows it to be more flexible. A better solution would be to make sure that the spring bars and the tow vehicle axle springs are properly rated for their loads and to install good shock absorbers.

[TundraBay]

Porpoising is a problem on concrete roads when the expansion joints are just far enough apart compared to your wheelbase and speed.

The bounce from the joints is just right to reinforce the rig bounce as it goes down the road. Sometimes this porpoising can be reduced by removing spring bar tension on the hitch which allows it to be more flexible. A better solution would be to make sure that the spring bars and the tow vehicle axle springs are properly rated for their loads and to install good shock absorbers.

That's exactly what happens to me on a few concrete highways in Central Wisconsin with my 5th wheel! Usually I just slow down a bit and the problem goes away. (Maybe I'm overloaded?)

[Sean Woodruff]

Porpoising and bounce are the same thing. It is a weight distribution issue. Like someone above said, try resetting your hitch. Sometimes it is just a matter of fine tuning the entire wight distribution and it will go away.

[cwit]

If you have airbags you can pretty much forget the shocks. I would say it's in your hitch. I would try less air in airbags It sounds like you may be bouncing on air. I have this problem if I put to much air in.

[TundraBay]

Originally Posted by cwit

If you have airbags you can pretty much forget the shocks. I would say it's in your hitch. I would try less air in airbags It sounds like you may be bouncing on air. I have this problem if I put to much air in.

I'm not sure of this cwit, because if there's inadequate damping on rebound (which I understand the non-TRD suspension may have) better shocks will slow down the bounce. I'd think what Jowett wrote makes sense. Although you are right in that too much air can make it feel like you are on something hard or non-compressible. Especially if there's very minimal effective hitch weight due to weight distribution.

[campertom]

I've played with the air bag pressure and hitch settings quite a bit. I know well what it feels like to have the air bags at too high a pressure.

In my opinion, the bounce begins when the trailer's back end rises on a bump, pushing the nose down and thereby pressing down on the truck. I expect this part of the effect is probably unavoidable, but the rebound bounces (after shocks) should be avoidable to some degree. I tend to agree that better shocks sound like they would smooth out the entire bounce experience.

I'm not even sure the air lifts were a good idea. The back end of the truck is far from being bottomed out. With WDH in place (and minimal pressure in the air lifts), the back end drop with a load is only about 1/2" lower than no load. After reading a bunch of other posts, I'm wondering if a set of super springs would have been a better choice than air lifts. It has occurred to me that my P rated tires (stock tires) could be part of the bounce problem. I'm thinking that I will try shocks first, then tires, then SuperSprings. My tongue weight should be a bit higher - I'm at 12% of total now. But, payload is a concern and limits there make it difficult to push the tongue weight higher on this (otherwise very capable) payload handicapped truck.