RE: [A/S] Re: airstream Ebay

["David & Bret" <dtbw_1999@xxxxxxxxx>]

Hunter,
The rims and tires on most A/Ss typically have excess capacity (if inflated
to max tire pressure), but the actual axle is another issue.  On a Henschen
axle, the axle is also the suspension and that is where the problem lies.
For a Henschen to work properly, it needs to be loaded to a significant
amount of its rated capacity.  If it is way overrated, it will result in
insufficient absorption of road bumps/etc (ie stiff ride), if
underrated/overloaded it will bottom out and have no ability to absorb
anything (either of which will shake the trailer to pieces over time). So
the magic is to have the proper Henschen axle for the load.  In selecting
axles, A/S takes into account the amount of GVWR that is actually carried as
hitch weight, so it is not uncommon to find that the combined axle rating at
or slightly below the GVWR of the trailer (that is the case on our 2002, 19'
Bambi).  To tell if you have exceeded the capacity of the axle take the
Henschen tour on Inland Andy's website as it has a drawing of how a properly
loaded Henschen axle looks (the swing arm should be parallel to the ground).
If the swing arm is deflecting upwards beyond parallel, then either the
rubber torsion portion of the axle has failed or the axle is being
overloaded.  

As for changing to different rim/tire combinations on an A/S, that poses
potential problems due to the clearance at the top of the wheel welds (ie
vertical travel of tire as moves up and down due to road conditions).  A/S
makes the wheel welds just big enough to provide clearance for the original
rim/tire combination at max upward tire travel. Of course you could go to a
larger rim AND a lower profile tire, making the combination have a similar
overall diameter similar to the original.  Moving from D to E range tires is
not a good idea as it makes the trailer ride significantly rougher (again
the whole system is designed to function in harmony) due to the stiffer
sidewalls of higher load range tires. BTW, going to a larger rim and lower
profile tire combination will have a side effect of making the ride rougher
as the lower profile tire has less sidewall flex so more of the road
conditions are transferred to the axle (and therefore to the trailer) rather
than being absorbed in the tire.  

If an A/S has been modified and/or loaded significantly beyond the original
GVWR, not only is the Henschen axle(s) capacity most likely being exceeded,
but the frame as well.  A person may get away with it for years, but sooner
or later, something will give.   

David