Bed bounce complaint to Toyota

I just ordered them! I am very hopeful!!

 

Yeah so I'm! I I'm doing a full overhaul on the rear for a MOAB trip I'm going on in a few weeks with a 7000lb load behind me.

TRD sway bar
Coach builder 1" shackles and bushings
Firestone ride right helper bags with OBA

 

Wth is bed bounce, this is my 3rd truck and either I don't complain or I've never experienced it.

 

Watch the baby in the back during the bed bounce. The rear of the truck literally bounces so bad it rattles your teeth.
https://www.youtube.com/watch?v=YGXFGVaJsiw

 

You got a lift on your truck? Yeah I'm all over Texas and the closer you get to Louisiana, the worse the roads get.

 

Yeah mine was bad before. I thought a shock blew out!

 

My order has the bushing kit (1) for $45. Did I need something else?

 

No, that's it.

 

Bed bounce is due to the trapezoidal rear leaf spring setup.. Look close. Not parallel by bad design. My co-workers 8ft bed DC has the same issue. Good reason for the next gen Tundra to fix that problem. Don't want to go redux the physics of this again. My AAL seems to have dampened it somewhat in combo with OME shocks. Deavers may eliminate/dampen it too. Can't see how shackles will affect bed bounce. I could be wrong, but trapezoidal spring setup causing bed bounce is hard to fix. Props to the first person to fix this. Be sure to let Toyota engineers know...

 

My 2008 DC 4wd with a 3/1 lift/level kit and stock wheels/suspension doesn't bounce much at all even with nothing in the bed. Maybe the leveling kit helps. My old T100 bounced and a 50lb bag of sand from Home depot stopped it when on long trips. I don't think it takes much weight back there to dampen the problem. These trucks are designed to haul a big load, and when empty you are going to get a bouncy bed, no doubt about it. Having driven pick up trucks of all kinds over the years I would say it is pretty normal, especially without a leveling kit.

 

You usually only experience bed bounce on segmented cemented freeways and at a certain speed. It's all about resonant frequency. (caused by the poorly designed rear trapezoidal spring set up that we have on our Tundras.)

 

Matt you nailed it! The spring setup narrows by 10 inches at the rear, and it's nothing more than a gimmick. It would also help to elimate the unreinforced c-channel frame behind the cab. These two design flaws create bed bounce. End of story.

 

Finally, some one else gets it!!!! I was beginning to think that no one else actually takes a real good look underneath.

 

My only question is then how come everyone that replaced the shackles with the CB shackles said the bounce went away?

 

Were they driving on the 405 segmented cemented freeway everyday day at 55 to 65 mph? Too many people with C Maxes , DC's of all bed lengths have issues on all Tundra forums, shackles or not. Find it very hard to believe that shackles would fix this problem by itself. CB shackles do nothing but give you some more lift. An inch or so. I'd like to see some comprehensive empirical proof of CB shackles solving this problem.

 

Its not the shackle itself its the bushings from what i'v been told.

 

The springs/suspension is working (increase travel). My PRO has bed bounce (I can see it in my rear view mirror), but the suspension and springs work well and nothing is transmitted into the cab. The ride is very smooth.

 

go figure I ask and ask and ask and start threads and file complaints and nobody says a word until after I spend $300.

 

I go by facts, not what I've been told. This has been an ongoing issue since 2007. It's all about the trapezoidal design. Bushings have nothing to do with it. I sympathize with you. I'd like to get some CB's for some more minor lift, maybe 1 inch to regain some height in the rear when towing, not to "fix" bed bounce. Not to mention the CB's are are best on the planet.

 

I think what is being lost here is "what is bed bounce". I'm not talking about your bed bouncing around when driving off road, dirt roads, pot holes, etc. The reported "bed bounce issue" is the constant pain in the ass cyclic bouncing at certain speeds on certain cemented freeways that all 2nd and 3rd gen Tundras experience. When I'm towing, it goes away. Unloaded?? Shackles/bushings fix it?? I don't think so.

 

This piece below is from four wheeler magazine...

"Shackles are a vital part of a leaf sprung suspension. Flexing of the elliptically-shaped leaves changes the straight line distance between the spring pack's mounting eyes. A shackle is placed at one end of the spring pack to allow for this change in length.

Wheel travel and ride height can be increased, within reason, by increasing the length of your suspension's shackles. This is a relatively simple and cost effective way to fine tune your ride's ride."

The guys that go with CB shackles, and report less bed bounce, may be onto something in terms of "fine tuning" the ride. For Trackers sake, I hope so.

 

I hope so to. Problem is how force and tension is applied. Force and tension act equally on parallel setups, front to rear. Force and tension acts entirely different with trapezoidal setup from front to rear. Elliptical has nothing to do with parallel or trapezoidal setup. There have been many different shackles available for the Tundra since 2007. CB's are the toughest. That's the only difference. The only thing in common with parallel and trapezoidal spring setup is that the springs are elliptical. Was the Four Wheeler write up considering typical parallel rear leaf spring setup? I've been reading Four Wheeler mag since the mid 70's. Good magazine. I still get it.

 

Matt, Four Wheeler mag was not addressing trapezoidal per se, but more about a slight increase in wheel travel and ride height with a longer shackle.

My PRO has about 1.5" of increased travel in the rear with the PRO suspension, and I float over those concrete sections with no trace of bounce into the cab.

Now could it be that the CB 1" shackle is just enough increase to tune out the felt bed bounce? Be interesting to see what Coachbuilder has to say on shackles vs. bed bounce.

 

One thing to consider is that your Pro has a much superior suspension, front to rear, to begin with over our non-Pros that may actually off set the associated bed bounce problems "We non-Pros" have. The addition of the CB's sounds like it is attenuating (helping) the issue. Our NAVLAP accredited Metrology lab here in Denver has multiple capabilities, including torque, force, pressure, and tension to name a few. It would be easy to demonstrate what the affects of trapezoidal "skew" has on those physical properties. We are not a testing lab per se, but it would be easy to set up a test fixture to demonstrate the various effects, how changing the straight line distance from a fixed point can affect a parallel vs trapezoidal setup. Not easy but doable. Not sure if Coach Builder can get the empirical data that we could come up with. The main thing is that if using the CB's helps...go with it. The more folks that go that route, with positive results works for me. We also need to know whether stock suspension or modified. That's the best data to pass on. The more the merry-er.

 

The trapezoidal skew essentially cuts the corners off the conventional rectangular frame layout with springs parallel, and the result: a tuning fork that creates a vibration that over powers the capabilities of the suspension.

Let's contact Coachbuilder and get his take on "bed bounce and shackle length."

 

A good method to verify is to use strategically placed accelerometers with a Dytran/PCB current source connected to a portable data logger or HP 34401A DMM. A FFT scope could be used. It's easy to measure before and after vibrations. The accelerometers could be attached to the trucks' springs or the bed itself. Coachbuilder could get someone to perform the test. It would be a good selling point. Anything that helps lessen the bed bounce is a good thing.

 

Matt, are you sure you're not Dr. Emmett Brown from Back to the Future?

 

Well my shackles are on order, bring out the equipment lol