Disclaimer: Okay so I'm a Mech Eng., but i don't specialize in cars trucks I and could be completely off base.
The first time I looked at the trapezoidal leaf springs setup I thought, cool, less axle wrap, more side/side stability. Then, after a few rides down the 880 here in the SF bay with my fillings falling out, as they say, I gots ta thinkin'
Trapezoidal leaf springs will flex in two planes (i.e. they wont try to just push the axle up/down but side/side too, towards/away from itself?) just think about it, that's how the things work. Problem: shocks in the conifiguration installed on our trucks damp up/down, not side /side. As I said before I'm not much of an expert but i had enough vibrations in my dynamics class to know that any undamped system has the possiblility to reach resonance (freeway bounce in our case).
My opinion only. But interesting thought maybe? Lets hear some thoughts.
Tom
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2007 Tundra DC Loooong Bed 5.7L 4x4 Slate
i had enough vibrations in my dynamics class to know that any undamped system has the possiblility to reach resonance (freeway bounce in our case).
Tom
Which would explain why those who do experience it claim that it gets worse and peaks at a certain speed, i.e., wave frequency. Condures up the image of an out-of-balance washing machine going thunk, thunk, thunk...
Negative marketing. I wonder how much time the folks behind those videos spent experimenting with chock spacing, height, vehicle speed, etc, to find the resonance? The question is, will Toyota now allot time and resources to place a Ford on a shaker table and find some weird harmonic on a tie rod etc, or will they concentrate on forwarding their own product?
Interesting theory, but I would have to think the Toyota Engineers would have considered this in their design analysis. It is more likely due to torsional flex in the frame and the resonance created from it. I truly believe you will see Toyota upgrade this "TripleTech" c-channel frame.
BTW, I too am a ME, but not in the Automotive industry. I am a Custom Machine Designer for factory automation. I design frames all the time and know what vibration can do. I have been doing this for nearly 20 years. But again, like you, not in the automotive industry, so my opinions are based on Engineering principles in general.
Could be the frame for sure... where I work in the hated oil industry we fill our pump frames with resin to try to get the natural freq well out of the operating range.
Anywho, I still think the springs are acting like springs in the horizontal plane undamped and causing heartburn. At least they must be a contributing factor? Then again I mostly do process flow and metallurgy work these days so I may be losing my edge.
I guess I could always go out there and cut off my springs and weld them in straight for a data point . As soon as someone makes a decent long travel shock for the rear I'll be bolting them in and see what happens. Until then I'll just bounce along my merry way. Bouncy, bouncy, bouncy..........into the sunset.
__________________
2007 Tundra DC Loooong Bed 5.7L 4x4 Slate
Disclaimer: Okay so I'm a Mech Eng., but i don't specialize in cars trucks I and could be completely off base.
The first time I looked at the trapezoidal leaf springs setup I thought, cool, less axle wrap, more side/side stability. Then, after a few rides down the 880 here in the SF bay with my fillings falling out, as they say, I gots ta thinkin'
Trapezoidal leaf springs will flex in two planes (i.e. they wont try to just push the axle up/down but side/side too, towards/away from itself?) just think about it, that's how the things work. Problem: shocks in the conifiguration installed on our trucks damp up/down, not side /side. As I said before I'm not much of an expert but i had enough vibrations in my dynamics class to know that any undamped system has the possiblility to reach resonance (freeway bounce in our case).
My opinion only. But interesting thought maybe? Lets hear some thoughts.
Tom
Not sure about that. I don't believe they are mounted with "camber" (for lack of better terminology), so as long as the mounts are parallel to the ground, they are still just cycling vertically (up/down). The mounting points are just wider at one end of the spring pack to possibly give more stability.
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Ben
1996 Lexus LX450, 129k, front/rear factory locking differentials, Cooper STT 285s, OME 850/863 suspension lift, CDL/Pin 7, 30qt freezer, 2@aux fuse blocks, aux powerpoint, 850w inverter
1998 Lexus LX470, 139k- SOLD
1993 Land Cruiser, 198k- SOLD
Not sure about that. I don't believe they are mounted with "camber" (for lack of better terminology), so as long as the mounts are parallel to the ground, they are still just cycling vertically (up/down). The mounting points are just wider at one end of the spring pack to possibly give more stability.
Maybe... if you have had some phys. draw a quick free body diagram (that's what I had to do to convince myself). you'll see force gets sent in a new direction out of plane when compressed with new design. This new force is restricted (pinned) by the axle, storing energy in the spring. Remember when you compress a leaf spring it gets longer in front back dir and shorter in up/down dir. As in they stay the same length but their shape changes. Then again i've been wrong many times and your opinion may be the right one (i learned this is the humiltiy required to live with a woman).
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2007 Tundra DC Loooong Bed 5.7L 4x4 Slate
Maybe... if you have had some phys. draw a quick free body diagram (that's what I had to do to convince myself). you'll see force gets sent in a new direction out of plane when compressed with new design. This new force is restricted (pinned) by the axle, storing energy in the spring. Remember when you compress a leaf spring it gets longer in front back dir and shorter in up/down dir. As in they stay the same length but their shape changes. Then again i've been wrong many times and your opinion may be the right one (i learned this is the humiltiy required to live with a woman).
There is a shackle at the end which lets the spring lengthen as it is compressed, I still can't see how there is any force directed anywhere other than straight up/down, the pivot points on the shackle and frame appear (going by pictures here) to be mounted so the springs go up/down, without camber.
__________________
Ben
1996 Lexus LX450, 129k, front/rear factory locking differentials, Cooper STT 285s, OME 850/863 suspension lift, CDL/Pin 7, 30qt freezer, 2@aux fuse blocks, aux powerpoint, 850w inverter
1998 Lexus LX470, 139k- SOLD
1993 Land Cruiser, 198k- SOLD
There is a shackle at the end which lets the spring lengthen as it is compressed, I still can't see how there is any force directed anywhere other than straight up/down, the pivot points on the shackle and frame appear (going by pictures here) to be mounted so the springs go up/down, without camber.
I smell what ur smoking man but let me draw a quick pic, scan it, then u'll see. or not as I said I may be wrong and u may be right.
Peace T
__________________
2007 Tundra DC Loooong Bed 5.7L 4x4 Slate
Disclaimer: Okay so I'm a Mech Eng., but i don't specialize in cars trucks I and could be completely off base.
The first time I looked at the trapezoidal leaf springs setup I thought, cool, less axle wrap, more side/side stability. Then, after a few rides down the 880 here in the SF bay with my fillings falling out, as they say, I gots ta thinkin'
Trapezoidal leaf springs will flex in two planes (i.e. they wont try to just push the axle up/down but side/side too, towards/away from itself?) just think about it, that's how the things work. Problem: shocks in the conifiguration installed on our trucks damp up/down, not side /side. As I said before I'm not much of an expert but i had enough vibrations in my dynamics class to know that any undamped system has the possiblility to reach resonance (freeway bounce in our case).
My opinion only. But interesting thought maybe? Lets hear some thoughts.
Tom
Umm, I'm not sure about all the tech stuff, but one thing I can agree with is the fact that I almost lost my teeth during a ride on one of those uneven freeways. I mean my glasses kept vibrating loose off my nose. What the hell were Toyota engineers thinking?
Ever look in your rear view mirror when the bouncing happens? The bed is not really bouncing much. Next time this happens, think of an imaginary horizon equal to your tailgate. See how much the tail gate moves past that horizon in both directions. Also, the frame flex (according to ford) was torsional flex. I don't have a problem with that as when the bounce happens it the rears wheels are syncing with the front wheel hops. (Due to shock valving?)
Has anyone taken a stopwatch and try to estimate the frequency of the bounce yet? Crude but might get you in a ballpark figure of what freq you want to eliminate. I imagine if a company like Monroe can adapt one of their dual frequency shocks for the truck, might just eliminate the problem.
Is there any aftermarket shocks available for the 07Tundra yet?
Umm, I'm not sure about all the tech stuff, but one thing I can agree with is the fact that I almost lost my teeth during a ride on one of those uneven freeways. I mean my glasses kept vibrating loose off my nose. What the hell were Toyota engineers thinking?
Rather than have some of us play automotive engineers, or second guess what the actual engineers spend hundreds of millions of dollars and thousands of miles testing and designing, two things need to be done. First, bring the truck back to the dealer and see if you can recreate this "tooth loosening" ride, and then second, take, say, a Corolla down the same road, and then a competing 1/2 ton truck. If the other vehicles ride acceptably and the Tundra still doesn't, only then can you state with a real degree of certainty that there is something "wrong" with the truck. So far, all we are seeing here are subjective comments about the ride of a heavy duty 1/2 ton truck. I drive trucks for a living, and sometimes they just ride rough, thats why they're trucks. That said, I cannot for the life of me figure out what all the fuss is about the ride. My Crewmax rides like a dream, empty, loaded, towing, rough roads, whatever. I also wonder if the people complaining have the TRD package or not (mine does, and I was very impressed at how it sucked up the chop on some dirt two tracks leading to our mx track. I also for the life of me don't understand all this concern about "bed bounce". Beds have bounced (or flexed independantly of the cab) on any truck I've owned if you put them on rough enough terrain. I've owned over the years-75C10-78F150 4x4-92F150 4x4, 92 Ford Ranger, 95 F250 4x4, 99 F350 4x4, and several commercial trucks, as a basis for my opinion. I guess what I'm saying is that I haven't heard anyone say something like, "my (insert any other brand of truck here) rides like a dream down the same stretch of road."
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2007 4x4 5.7 Black SR5 CrewMax with TRD pkg and other miscellaneous options
2007 Honda CRF450r
2006 Yamaha Apex GT
I may just be lucky so far but my Tundra Double Cab 2 wheel drive is not much rougher than by 3/4 ton Suburban 4X4 was. I realize people are concerned with comfort issue but I would be more concerned re metal fatigue issue if the vibrations are as bad as some are indicating. If Toyota engineers did not anticipate these levels of energy input and resonance there may well be strategic metal part failures.
I smell what ur smoking man but let me draw a quick pic, scan it, then u'll see. or not as I said I may be wrong and u may be right.
Peace T
I thought about it a bit and figured that with the trapezoidally mounted leaf springs that the movement of the axle is still in one plane (vertical). Any force transferred laterally, under compression, due to the mounting of the leaf springs would be cancelled out by the other side (all things being equal).
Its kind of analagous to why airplane wings are mounted angled up a bit. The direction of the force of lift from the wing is normal to the plane of the wing, but being angled up a bit introduces a force in the x-direction (when the lift force is resolved into X and Y components) which is cancelled out be the wing on the other side. I think the same principle applies here (get it??). Hard to explain...What do you think?
Cause of the Bed Bounce IMO
Re: Cause of the Bed Bounce IMO
. As soon as someone makes a decent long travel shock for the rear I'll be bolting them in and see what happens. Until then I'll just bounce along my merry way. Bouncy, bouncy, bouncy..........into the sunset.
Re: Cause of the Bed Bounce IMO
Linear Mode
