Bouncy Bouncy when towing

[tomhole]

2005 Tundra DC, 2WD SR5. Towing a 5,000 lbs travel trailer, 680 lbs hitch weight. I have a WDH that spreads the hitch weight about evenly across the 4 axles (2 on Tundra, 2 on trailer). I load 800 lbs cargo in the truck (humans and gear). Truck and trailer set perfectly level with a well distributed load.

My issue: I get what I consider excessive bounce. Not terrible, but enough that the kids can't color while travelling without creating a Picaso.

So, whadya think would help? I was thinking heavy duty Bilsteins <sp>. Just have the regulars on now. Front and back or just back?

Timbrens maybe?

I can live with it if the fix is expensive.

Tom

[2000LtdKen]

Tom,

A few suggestions:

Inflate your tires to the maximum listed on the sidewall.
Tighten up your weight distribution hitch another link

On the more expensive side. Replace your tires with a higher load rated tire. Our trucks come with Load Range C. Load Range D and E are available but your truck ride will be harsher all the time. I personally like that kinda ride but its not for everyone.

Ken

[HBjeff]

I would get the D rated tires. the stiffer sidewalls wont bounce so much. you are hauling quite a heavy load there, might as well not ride on car rated tires.

some heavier duty shocks will help out some too, but like the tires, they will also stiffen up your unloaded ride

[KLS]

Our trucks come with SL (Standard Load) tires, not Load Range C. Upgrading to LT 265/75-16 Load Range C is a good move when tires are needed.

The best way to overcome the bounce is to install four heavy duty shock absorbers. I have the HD Bilsteins, and they work much better than the original whimpy shocks. I've also added the Monroe shock retro-fit kit to my trailer, and that helps. I would not add helper springs, Timbrens or others. You already have your w/d hitch correctly adjusted, being level as you say. Do inflate all the tires to the max listed on the sidewalls.


Ken

[mustang67408]

Air bags will help that BOUNCE.
They arent for extra weight capacity, just to help what you already have.
In my truck they help side to side sway along with my sway control device.
They also help the bouncing along with my WDH.
You might try tightening the WDH hitch 1 more link in the chain.

[fastone01]

Had the same issue here.

Blistien 5100 did not help. I had it when I got the trailer

Hard side wall tires. I am running 20s rim/tire combo and crank the psi to 46. did not help. Made the truck more stiffer when hitting bumps.

put helwig sway bar - help a little especially when cornering but the loffy bounce is still there

What fix my issue is upgrade my Wieght distribution hitch from 1000lbs bars to 1400 lbs bars.

Try cranking yours all the way up. If is still there after doing so, go get the higher rated bars.

Note: If you do go with a higher rated bars, don't crank it up like the old one is setted on. To much will start loading your front tires and develop bad tire/ supension wear.

Originally Posted by tomhole

2005 Tundra DC, 2WD SR5. Towing a 5,000 lbs travel trailer, 680 lbs hitch weight. I have a WDH that spreads the hitch weight about evenly across the 4 axles (2 on Tundra, 2 on trailer). I load 800 lbs cargo in the truck (humans and gear). Truck and trailer set perfectly level with a well distributed load.

My issue: I get what I consider excessive bounce. Not terrible, but enough that the kids can't color while travelling without creating a Picaso.

So, whadya think would help? I was thinking heavy duty Bilsteins <sp>. Just have the regulars on now. Front and back or just back?

Timbrens maybe?

I can live with it if the fix is expensive.

Tom

[tomhole]

I'm at 3 links and have just shy of 200 lbs on the front (out of 680 lbs hitch weight). That's enough for me. I've been wanting the Eqaul-i-zer instead of the Reese anyway, so might just switch to the 1000 lbs Equal-i-zer vs my 800 lbs Reese. Not a big fan of the friction sway control either. Works ok, just another thing to hook up and adjust.

Tom

[ricqik]

I know the bounce you're talking about. This isn't suspension bounce, it's frame flex bounce. Happens to every truck, trust me. I tow a 4k bassboat and some roads that have just the right syncronized time with the frame flex causes some pretty interesting bounces. Higher dampening shocks does help but won't eliminate it. My brothers titan does it too to a lesser extent and my cousins previous seirra does it even more than my tundra. I even watch the O'so mighty new f150's with supposedly the stiffest 1/2ton frame do this but to a lesser extent as I drive along side them. The trailer frame flex also contributes to this. The less the trailer flexes the less bounce I get. In my case boat frames aren't stiff.

[fastone01]

The difference in the bar diameter between the 1000 bars to 1400 lbs bar was the key for my setup to eliminating the bouncing effect. The higher rate bars are more stout and rigid than the once I replace. Shorter too by 1 inch. Almost the same weight.

Running the hensley here. Very expensive, but atleast my wife get to drive the truck and trailer with confidents. I get to relax!!! I think that is worth the money!

Originally Posted by tomhole

I'm at 3 links and have just shy of 200 lbs on the front (out of 680 lbs hitch weight). That's enough for me. I've been wanting the Eqaul-i-zer instead of the Reese anyway, so might just switch to the 1000 lbs Equal-i-zer vs my 800 lbs Reese. Not a big fan of the friction sway control either. Works ok, just another thing to hook up and adjust.

Tom

[tomhole]

Originally Posted by ricqik

I know the bounce you're talking about. This isn't suspension bounce, it's frame flex bounce. Happens to every truck, trust me. I tow a 4k bassboat and some roads that have just the right syncronized time with the frame flex causes some pretty interesting bounces. Higher dampening shocks does help but won't eliminate it. My brothers titan does it too to a lesser extent and my cousins previous seirra does it even more than my tundra. I even watch the O'so mighty new f150's with supposedly the stiffest 1/2ton frame do this but to a lesser extent as I drive along side them. The trailer frame flex also contributes to this. The less the trailer flexes the less bounce I get. In my case boat frames aren't stiff.

Interesting. I have SEEN the back of my Tundra flexing while I'm towing. I can see the gap between the bed and cab in my mirrors and that clearly indicates that the frame is flexing.

I also agree that the WD bars essentially become a part of the suspension system. Using stiffer ones might be the answer.

Thanks for all the input. Got some budgeting to do.

Tom

[tomhole]

Just an update.

I checked my bars and they are 800 lbs bars with 640 lbs hitch weight. I decided that my best first step was a new set of rear shocks. I have non TRD shocks and even when just hauling heavy loads in the bed, never like the feel they offer. So, I'm going with a set of Rancho RS9000X adjustable rears shocks. I like the adjustable part and other owners have reported good results while towing.

I also played around with the number of links I take on the WDH bars. At 2 links, there is no weight added or removed from the front axles as compared to empty. With 3 links, I add about 100 lbs to the front axle and the rear sits at exactly the same height when not loaded with anything (i.e., the truck is still back end high). This is with an unloaded trailer and truck. When I load up for camping, the rear sags a little less than 1" at 3 links and too much with 2 links. So, it makes a difference whether the trailer is loaded or not as to how many links you take on the WD bars. I think I knew that already, but was good to verify. Also, I noticed no real difference in the ride with 2 vs 3 links with the trailer and truck empty. With both loaded, there is a big difference.

Tom

[KLS]

Change all four shocks. If you just stiffen the rears, they'll act like a fulcrum and cause more front end bounce. I really like the HD Bilstein shocks on my truck.

Also inflate your tires to the max shown on the sidewalls. I towed a trailer one time and forgot to air-up the tires. Lots more bounce than usual.


Ken

[cupidstoy]

not an experienced towing guy with the tundra, but this sounds like a harmonic frequency thing to me. i have towed a lot of trailers and the thing you want to avoid is a magical accident of having the bounce of the trailer be a multiple of the bounce of the truck - essentially reinforcing a naturally occuring resonant frequency. don't know exactly how to describe it, but you end up with a natural frequency that reinforces itself. for example the distance between the wheels on your trailer and the axle on your truck may be the same or twice the distance between the front and rear axles on your truck. then, when the truck bounces over a bump, the suspension is just bottoming out when the trailer tires hit it and you get another bounce out if. does that make sense? i'm sure ray or some other expert can explain it better.

i think you have accidentally put together a configuration that reinforces itself. the thing to do is change something that affects the resonant frequency of the system as a whole so you don't get the reinforcement or minimize it. if it's a high frequency bounce, changing tire pressure one or more places might do the trick. if it's a larger waveform, changing the damping on your shocks might do it. if its a really long, loping bounce, you might have to change the location of the axles on your trailer if that 's possible. without seeing your setup, it's hard to recommend a fix. anyway, your post is several months old, so you might have figured out a fix by now.

another possibility is having a longer waveform additively effect a shorter waveform. for example: the suspension on your truck has a natural frequency of .5 seconds when you hit a bump on the freeway at 65 miles an hour. the distance between the rear axle of your truck and the axle on the trailer results in the trailer wheels hitting the same bump your truck just hit only .75 seconds later. now, every 1.5 seconds, you'll have a bigger bounce because it is being reinforced. (.5, 1, 1.5, 2, 2.5, 3 etc for the truck and .75, 1.5, 2.25 and 3 for the trailer).

i realize that may not make much sense but it's the best example i could think of. either way, the solution remains the same. change something in the system so the resonant frequency at your preferred cruising speed goes away. adjust tire pressure on one or more axles, change tire size, change distance between axles, change suspension damping characteristics, change weight distribution, etc. with a little experimentation, you should be able to figure something out that isn't too expensive.

my personal experience with towing is that longer trailer tongues, thus larger distance between rear axle and trailer axle, results in smoother ride. also, distributing the weight correctly makes a big difference.

post an update if you get a chance....

[Ready2Rip]

My '04 DC used to bounce when towing my 22' toyhauler with WD hitch. I installed Firestone airbags and the bounce is gone. Smoothed out my ride, too. One of the best mods I've done.