[A/S] Re: tongue weight and suspension

["Matt Worner" <wornmatt@xxxxxxxxxxxxxx>]

<snip> confident in the grain scale.
> Matt, your F350 has heavier suspension than my F250, correct? F250's 
> are 3/4 ton, and F350's are 1 ton I believe. Where in the suspension is 
> the difference- leaf springs, shocks, or trunion springs? 

Actually on a diesel truck you are talking a couple of capacity 
pounds on the rear end suspension is the only difference.  The 
engine weight (along with the front drivetrain in a 4x4) make the 
front suspension virtually identical in both models (if I am 
correctly informed...)

I'm not sure 
> I know what trunion springs are..

The trunnion springs are the ones on your load equalizing hitch.  
They should be adjusted so that the "squat" of your truck is 
identical on both axles.  Take the whole shebang to a nice level 
parking lot, put a spot of masking tape on each corner of the truck 
and mark a measured point on each spot of tape.  Hook up and measure 
again.  All four marks should have dropped an identical amount.  If 
not you are out of adjustment on the hitch.  If the nose drops more 
(apparently not your problem) hitch is chained up too much, extra 
tail drop means chains are too long.

Note also that the trunnion springs are weight rated.  If you have 
the original hitch that came with the trailer they are rated for 10 
to 12% of 7100# (GVWR of trailer).  With an 1100# tongue you may not 
have enough spring to pick up the ball assembly to level the truck.  
You may want to find out what springs you have, and if they are 
still functional.

First, make sure the trailer is not overloaded.  With that rig you 
should be running at about 55psi tire pressure, if you need  a lot 
more you are a wee bit fat in the trailer.  Then level the truck 
with the trunnion springs.  If the trailer is out of level, the ball 
needs adjustment.

You can check needed tire pressure with an inexpensive infra-red 
thermometer.  (About thirty bucks at Radio Shack, and suprisingly 
accurate for the price.)  Tow the trailer as you normally would, and 
scan across the tread at the next rest stop immediately you arrive.  
If the tread temperature is constant across its width, you are 
correct, if notably cooler in the center, you are soft, cooler edges 
indicate over inflation FOR THE LOAD CARRIED.  My Sov runs at 54 
psi, but I have not weighed it.  I use it for weekending, so am no 
doubt a lot lighter than you would be as a full timer.

I also HIGHLY recommend the SmarTire sensors system.  They will 
alert you of increasing temperature in the tire as well as pressure 
changes out of the ordinary.  When a tire lets go it can really beat 
the bejabbers out of your coach.  Ask Hunter...
 
> FWIW, I think the truck used ride level when lashed up. At least 
more 
> level than it does now. I wonder if the heavy tongue weight has 
caused 
> some element of the suspension to soften..?

I would not discount that possibility.  How does she ride when 
bobtail?

Good luck, Happy Easter, and when you coming to New Mexico. (To join 
me in the witless protection programme: hugs, Hunter.)

> Cheers,
> 
> Chris
> 
<snip>

Matt