Owners Manual Warning - Stiff T.V. Springs
 

My 2007 Safari Owners Manual has a note and warning at end of page B-1.

NOTE: Be realistic when ordering heavy duty springs. Only springs heavy enough to support your loaded vehicle (not including trailer) are necessary. Too harsh of spring rate will only shorten the life of the tow vehicle and trailer, and make your journeys less enjoyable.

! WARNING: Too stiff of springs can hinder the action of the weight equalizing hitch and prevent the transfer of weight to the front of the vehicle.

What is the meaning of these statements?

A vehicle's suspension system is designed for many reasons.

It helps keep all 4 wheels on the road
Absorbs bumps and road irregularities which add to passenger comfort and vehicle control.
Reduces wear and tear on the vehicles structure and components

If the suspension is over built and unnecessarily stiff or firm it will reduce all or many of the above mentioned benefits.

The overly firm suspension can also hinder the positive effects and reduce the action of the WDH by restricting movement and or adding stress to the trailer frame and structure.

Excessive spring rates cause damage, don't go overboard.

Listen to what others have been saying here for years.

Match your hitch, TV and trailer.

Your Airstream has soft springs in it for a soft ride that absorbs the road shocks and does not transmit them to the body of the trailer or the contents. if you mount it to a stiffly sprung TV that will in effect increase the stiffness of the trailer's suspension when using fairly stiff Weight distribution bars and cause more road shock to be transmitted to the trailer body and its contents. You still need to have suspension stiff enough that it does not bottom out when it comes in contact with the average roughness. If it bottoms out the whole suspension becomes rigid and all the effect is lost. The suspension also needs to be stiff enough that the steering geometry remains constant and the truck does not wallow when trying to steer around things or make lane changes.

Spend a quality evening reading all the commentary about too much truck, too strong weight distribution springs, etc. and how it affects (damages) the Airstream trailers. This topic can keep you reading far into the night.

The first "NOTE" seems fairly straightforward to me, do not get heavier springs or truck than you need, or your will damage your t.v., trailer, and have an uncomfortable ride.

The second "! WARNING" is less clear. To me, it suggests that too stiff of springs hinders transfer of tongue weight to the front axle. Does that mean most of the tongue weight is split between the rear axle and the trailer axle(s) on the too-heavily sprung tv, and only with additional tightening can weight be restored to the front axle? This further suggests that a heavily-sprung tv would have a more rigid connection at the hitch, than a tv more closely matched to the tongue weight of the trailer.

Oh boy, this has been argued here once or twice, with no resolution. But that is NOT what I am looking for. I am ONLY looking for an understanding of my Owners Manual.

The inventors gave us the Hensley; now if they could only get rid of those d@#% weight distribution bars.

I just drew a diagram using the ultimate stiff suspension. ( axles bolted to frame). After messing with that with what I learned about statics in physics, I am sure that second statement is not true as they wrote it.
I don't know what they are thinking, but I am thinking there is some fuzzy logic involved. They also lost some credibility with me by saying "too stiff of springs" instead of "springs too stiff" or " too stiff springs" :lol:
Regards,
Ken

Another part of the physics is that it takes more effort to transfer weight on vehicles with a long wheel base compared to shorter wheel based vehicles.

Longer wheel based vehicles tend to need heavier bars to get the appropriate weight transfer.

I get more confused every time this subject comes up - I was happy with my TV-WDH-TT setup until I did some reading here. I still do not know if I need lighter weight bars or not. Equalizer says probably not - some say yes - Equalizer says their new e2 is different than other hitches. I can order 800 lb. bars but do I really need the expense - it has 1000 lb bars. I am only pulling a 71 overlander international with a 2006 GMC Sierra 4 door pickup with trailer towing package. I know I need new axles (which I will do in a couple months). But, now - do I or do I not need 800 lb. bars?

I changed how I hitched up after reading a particular thread on this subject
 

For what it's worth, this is the first time I have heard that Airstream owner's manuals now address this particular issue. Cool.

This particular thread starts out kinda slow as far as looking like it pertains to what you asked about. But, should you care to read & think about all of it, you will gain a deeper understanding about what your owner's manual is referencing.

Changes were made to my setup based on what I read.

Tom

DK....here is a pretty good read on wd hitches.

I really don't believe that a modern 3/4 suspension will be to stiff if set up properly with the correct hitch and wd bars. At least not GM anyway JMO :)

Do I hear, all of us really only need a well equipped 1/2 ton gasser for ANYTHING EVER MADE BY AIRSTREAM? I suspect the mother ship is tired of repairs due to 3/4 ton diesels that are not needed and making warranty issues already a problem worse. At some point it must be surfacing what Inland Andy has been saying all along. Over rigged equals repairs. At best, removal of the springs and full air ride must be the choice if you want the so called "relaxed towing" of a diesel.

Grammer police at your service
 

That is the way they talk in the midwest. It is perfectly understandable, but sounds horrible, somewhat like eubonics. They say similar things in New York as well, only they think it makes them sound smarter.

:huh: The "relaxed towing of a diesel?"

No..... you hear what you want, tow with whatever your comfortable with.

Been towing with 3/4's since 95 with no problems, to each their own.