A Possible Bed Bounce/Vibration Temporary Fix with a Foam Damper

[FlatironsDreamer]

Until Toyota addresses this with an official fix there's a highly detailed temporary fix detailed on the Tundra Headquarters site that provides some insight into the problem. I've reproduced the post here:

# Matthew Davis Says:
December 10th, 2007 at 2:34 pm
Hello everyone. I am the owner of a 2007 Tundra double cab 4X4 with the 5.7 engine. I have noticed the bed vibration since shortly after purchasing the truck in July. I had some time on my hands the other day, so I got up under the truck to see if I could identify the sourse of the vibration. Those of you who own this truck can go and grab the rear bumper and shake it up and down vigorously and you will observe independent motions of the bed and the cab. I began to realize that the frame has a harmonic frequency with a pivot point between the engine/transmission area and the rear axle area of the frame. (Visualize a guitar string.)You can get into the bed of the truck and stand directly over the rear axle and jump up and down, and you will find that it is almost impossible to make the same vibration that you can easily achive by applying pulsating pressure to the bumper or open tailgate. I thought about the idea of attaching some sort of weight to the rear bumper area, but as I considered the idea, I realized that this would only change the frequency of the vibration, but would not dampen it. It might even make the vibration more intense in the cab. So I thought about the idea of somehow canceling out the harmonics of the frame by creating a dampening device with a slightly different harmonic frequency attached to the area of the frame behind the rear axle as close to the bumper as possible. The logic here is that if you could CAUSE the frame to vibrate from this point, then it should be possible to DAMPEN the vibration from the same point. I decided to use the spare tire for this purpose so as not to ncrease the weight of the vehicle. I lowered the spare tire a few inches from the frame, and I cut out two peices of high density rubber foam and placed them in between the tire and the part of the frame that the tire is pressed against. I then retightened the tire to where the foam was snug between the tire and the frame. (The tire should be tight enough that it does not rattle.) This setup allowed the tire to “jiggle” slightly up and down, but at a frequency slightly higher than that of the frame harmonic. This effectively canceled out the frame harmonic and made for an amazingly smoother ride over rough, or washboard surfaces. It is also much more difficult to “shake” the truck from the tailgate area. Likely, when Toyota comes up with some sort of fix for this problem, it will use this, or a similar principle. In the meantime, the ride quality of my truck is much better. You can rest assured, that the springs are not too stiff, the shocks are not defective, the frame is not weak,and the tires do not cause this as long as they are properly balanced, and not out of round. (An out of balance or defective tire could easily magnify the problem, especially at the speed when the RPM’s of the tire match the frequency of the frame harmonic) Hopefully some of you will find this information helpful.

[medicdubs]

Sounds like it may work, could you be more specific about the foam? What size? Where did you get the foam, and perhaps some photos of the placement?

[shadyskins]

Originally Posted by medicdubs

Sounds like it may work, could you be more specific about the foam? What size? Where did you get the foam, and perhaps some photos of the placement?

He was just reposting someone else's post from another site

[Canadian_Yoda]

That's quite the idea...

Made me think of something else: has anybody who is experiencing the highway harmonics tried removing the spare tire? Perhaps Toyota's test mules did not have spare tires, and thus never experienced such a situation...

Just some random thoughts

[Wgasa84]

If I get home before it gets dark, I'll toss my spare in the bed and strap it to the front.

[metrictundra]

I wish there was a way to get some pictures of what was done and what was used.

[FlatironsDreamer]

Originally Posted by Canadian_Yoda

That's quite the idea...

Made me think of something else: has anybody who is experiencing the highway harmonics tried removing the spare tire? Perhaps Toyota's test mules did not have spare tires, and thus never experienced such a situation...

Just some random thoughts

That's a great thought. It still drives me crazy thinking how Toyota let this slip through their testing - it really makes me question Toyota's Q/A on this truck.

[narliec]

I know it's been a while since you have posted this temp fix. I have not been able to get this foam. Where can I get some? I don't think Toyota is doing anything about this problem. I was told California is the only state with complaints. Yeah right!

[Raybo]

You can find the foam or something like it that Flatiron described in the garden section of most home improvement stores in the form of a kneeling pad. At least that is what I am going to try.
I'll keep you guys posted.

[narliec]

Obviously I can't think for myself! Yeah I tried to look up high density foam on line and got nowhere. Thanks for the response. I will definitely give it a try as Toyota is not doing anything about this problem as of now. I am making a formal appointment with Toyota so it with be logged as (BED BOUNCE). If enough people do that then Toyota can begin to inspect the problem, Lord knows mine has allot of bed bounce. Even my dog doesn't like the truck. That's saying something.

[Art64]

Originally Posted by narliec

Obviously I can't think for myself! Yeah I tried to look up high density foam on line and got nowhere. Thanks for the response. I will definitely give it a try as Toyota is not doing anything about this problem as of now. I am making a formal appointment with Toyota so it with be logged as (BED BOUNCE). If enough people do that then Toyota can begin to inspect the problem, Lord knows mine has allot of bed bounce. Even my dog doesn't like the truck. That's saying something.

Try one of those exercise mats that are made of foam or hard rubber. I just used my wife's old wedge foam sandals and they worked. I wedge them on the front brackets where the spare tire comes to stop, then I used a ratcheting cargo strap to further tighten the spare tire.

[Austin Aggie]

Don't know that I've ever experienced this Bed Bounce, though I know a lot of folks here have. I have a RCSB, so that may be why?

Just curious, but could you use those round or hexagonal tube noodle foam things that they sell at walmart and other places as floaty devices for kids. You know the ones that people put under their arms and such.

[mattdaddy]

I have owned my 08 dc for about 3 weeks and have not experienced the "bed bounce" effect yet. I have read all of the suggestions to eliminate this very dangerous condition. Has anyone tossed the idea of the angled leaf springs as the reason. I thought about the model cars i use to race as a kid and having that sort of an angle would deffinately cause some kind of unwanted resistance when articulating. Try makeing a model with some pencils and see for yourself. If I am right Toyota should pay my Tundra off and give my wife a new Seqouia. Oh, and fix the bed bounce for everyone.

[Dysan911]

My 08 DC has it bad! It's like a teeter totter effect if thats what people call the bed bounce..

If I go over a really bumpy road I get that rear bed oscillation but just going down a half way decent road it's like the rear springs are so stiff and the shocks don't dampening worth a crap..

I may give that foam trick a try soon!

[cwit]

The foam used in the original post was knelling pads found in gardening centers.