[A/S] Patti, Safari 25' and Tahoe

["tmeeker" <tmeeker@xxxxxxxxxxxxxxx>]

Patti,

That weight difference is huge!  I thought the Safari's were going to "weigh
less" so they could be pulled by today's SUV's and trucks.

You say you have the bigger engine in your Tahoe.  Good, you will need it.
;)

But what is the differential drivetrain rear gear ratio?  An example of what
I mean is are the gears 3:50, 3:73, 4.10, etc.

The size of the engine matters of course.  However, the ratio of the rear
end that can haul the mail is also a huge part of that equation.  Having a
big engine with tall gears in the rear works out to not being able to pull
such a heavy load.

When we got our first Airstream it was a 1969 29' International Ambassador.
The curb weight was a bit over #5000.  The *first* pickup truck I had to
pull it with at the time was a 1987 Ford Supercab with the 351cid (5.8-liter
today).  I thought that this truck setup was great to pull this much weight.
Well, it was ... kinda.

You see, the big engine did OK *but* the rearend differential gears were
"too tall" to do a good job.  I had to upgrade my gasoline grade to Premium
to stop the pinging.  The pinging was due to the engine "lugging" and a
lugging engine will not build the needed power that comes from higher RPM's.
The lugging engine thus caused higher engine temperatures and the higher
temps caused the medium grade gasoline to light off too early.  This is
called "pre-ignition" which I'm sure you have heard of the term anyway.
Pre-ignition lights off the fuel before the piston gets to almost top dead
center which is where it should light off in a perfect situation.  As the
fuel lit off before getting to the best piston position even my large engine
couldn't make all the power it needed to.

Make sure you have the correct rearend gear ratio to pull this new trailer
you are getting.  The Tahoe easily pulled the older Airstream but that won't
be the case unless your entire drivetrain is setup to do so from the engine
all the way back to where the rubber meets the road.

By the way, my Ford that I used at the time had a gear ration somewhere near
3:50 or thereabouts.  This gear ratio was too tall to pull the trailer.
Flatlands it did OK but I didn't have sufficient power to do much but try
and keep up with the traffic.  The hills?  Forget about it.

My 2001 Ford Excursion how has a 4-speed automatic, diesel engine, 4:11
gears in the rear and it's also a 4x4.  This setup will now allow me to tow
over #10,000.  The amount that even this SUV could tow would be less if the
gear ratio was higher.

Tom