final drive ratio, gas mileage, other wear

Anyone have an idea of how much a typical towing package reduces
highway gas mileage and adds to engine wear, when not towing anything?
I'm talking about on a full sized truck or SUV with a V8. My thinking
is that the lower final drive ratio revs the engine more, increases
wear, increases noise, and lowers mileage on the highway. But maybe I
have it wrong, I'm hardly an expert.

The motivation behind my question is that I'm looking at buying a new
vehicle. The towing package is not an expensive option and even though
I don't to tow anything right now, it might be worth having over the
long run. But if it takes a noticeable toll on (the already terrible)
mileage, and/or adds to engine wear, then I'll pass on the towing
package.

Thanks for your advice.

On 2 Aug 2006 10:09:07 -0700, [email protected] wrote:

>Anyone have an idea of how much a typical towing package reduces
>highway gas mileage and adds to engine wear, when not towing anything?
>I'm talking about on a full sized truck or SUV with a V8. My thinking
>is that the lower final drive ratio revs the engine more, increases
>wear, increases noise, and lowers mileage on the highway. But maybe I
>have it wrong, I'm hardly an expert.
>
>The motivation behind my question is that I'm looking at buying a new
>vehicle. The towing package is not an expensive option and even though
>I don't to tow anything right now, it might be worth having over the
>long run. But if it takes a noticeable toll on (the already terrible)
>mileage, and/or adds to engine wear, then I'll pass on the towing
>package.
>
>Thanks for your advice.


There is a LOT of miss conceptions here. I have driven trucks in years
past over 200K with stock tires and 4.10 axles before there was even
OD trannies in main stream. Ressonable RPM does not hurt engines at
all though some like to belwive otherwise and feel you must cruise
below 2000 RPM for engine to last. WIth a gas engine cruises up to
around 3000 RPM (especailly towing) will not shorten life at all and
actually can increase it. You ave to remember something here, if your
load require 100 HP just to crusie, it has to produce that HP
regardless of RPM and the lower the RPM. the higher the cylinder
pressures and bearing loads to dleiver that power and the less power
resever availble at the RPM as well. The type and size of engine as
well as the planned load and terrain really determines best gear
ratios, not the gerieric rating from factory that are more fantisy
then reality on several models of all brands too. Lugging a engien
under a heavy load does far more damage than cranking it up some. But
people are looking for magic solutions for their SUV's and want to
believe that a 3.73 will give then better MPG i there OD equipped tow
vehcile when the opposite is true especailly when towing.
-----------------
The SnoMan
www.thesnoman.com

SnoMan wrote:
> On 2 Aug 2006 10:09:07 -0700, [email protected] wrote:
>
> >Anyone have an idea of how much a typical towing package reduces
> >highway gas mileage and adds to engine wear, when not towing anything?
> >I'm talking about on a full sized truck or SUV with a V8. My thinking
> >is that the lower final drive ratio revs the engine more, increases
> >wear, increases noise, and lowers mileage on the highway. But maybe I
> >have it wrong, I'm hardly an expert.
> >
> >The motivation behind my question is that I'm looking at buying a new
> >vehicle. The towing package is not an expensive option and even though
> >I don't to tow anything right now, it might be worth having over the
> >long run. But if it takes a noticeable toll on (the already terrible)
> >mileage, and/or adds to engine wear, then I'll pass on the towing
> >package.
> >
> >Thanks for your advice.
>
>
> There is a LOT of miss conceptions here. I have driven trucks in years
> past over 200K with stock tires and 4.10 axles before there was even
> OD trannies in main stream. Ressonable RPM does not hurt engines at
> all though some like to belwive otherwise and feel you must cruise
> below 2000 RPM for engine to last. WIth a gas engine cruises up to
> around 3000 RPM (especailly towing) will not shorten life at all and
> actually can increase it. You ave to remember something here, if your
> load require 100 HP just to crusie, it has to produce that HP
> regardless of RPM and the lower the RPM. the higher the cylinder
> pressures and bearing loads to dleiver that power and the less power
> resever availble at the RPM as well. The type and size of engine as
> well as the planned load and terrain really determines best gear
> ratios, not the gerieric rating from factory that are more fantisy
> then reality on several models of all brands too. Lugging a engien
> under a heavy load does far more damage than cranking it up some. But
> people are looking for magic solutions for their SUV's and want to
> believe that a 3.73 will give then better MPG i there OD equipped tow
> vehcile when the opposite is true especailly when towing.
> -----------------
> The SnoMan
> www.thesnoman.com

Hey SnoMan, thanks for the info. I do realize that from a simple
physics point of view the gearing makes no difference. But I'm
assuming that Ford engineers have good reasons for choosing a taller
final drive on non-towing trucks. Maybe it's just to reduce noise....
I don't know. I guess what I'm asking is, If I had two Expeditions
that were identical except for the final drive ratio, and I drove each
one from LA to NYC, moderately loaded and towing nothing, what
difference would I notice? Thanks.

On 2 Aug 2006 14:16:40 -0700, [email protected] wrote:

>Hey SnoMan, thanks for the info. I do realize that from a simple
>physics point of view the gearing makes no difference. But I'm
>assuming that Ford engineers have good reasons for choosing a taller
>final drive on non-towing trucks. Maybe it's just to reduce noise....
>I don't know. I guess what I'm asking is, If I had two Expeditions
>that were identical except for the final drive ratio, and I drove each
>one from LA to NYC, moderately loaded and towing nothing, what
>difference would I notice? Thanks.


Actually for a simple physics point of veiw, gears do make a big
difference, like having a longer pry bar where it takes less effort to
move the load with it. As far as what difference you would see. The
one with taller gears will downshift more on grades and with headwinds
and suck and oD will be about useless towing. The one with deeper gear
will handle OD much better and towing a lot better too. As far as the
"engineers" (and I am not picking on any one brand here because all of
detriot does it) They gear them tall to try to squeak out make MPG is
a rigged EPA MPG test for light duty model(the average speed for
highway test is 48 MPH and who drive 48 MPH on highway) On heavier
models there is the illusion that a taller gear will get beter MPG.
Maybe with a GM 8.1 or a Ford V10 or a deisel but not with a small
block gas motor in a big heavy truck because it does not have the
torque to handle it effectively..
-----------------
The SnoMan
www.thesnoman.com

You can still tow without a towing package, just not as big a load. I
wouldn't buy a towing package if I didn't have anything to tow. And
yes, low rpm saves gas, saves wear and tear etc. Your decision, but why
do you want a towing package if you are not going to tow?

As for differences, the towing gears will give better acceleration when
in high gear, but the non-towing set up will work fine and give good
performance. And yes, Ford engineers know what they are doing when they
design a towing vehicle as far as gear ratios etc.

SnoMan wrote:
> On 2 Aug 2006 14:16:40 -0700, [email protected] wrote:
>
> >Hey SnoMan, thanks for the info. I do realize that from a simple
> >physics point of view the gearing makes no difference. But I'm
> >assuming that Ford engineers have good reasons for choosing a taller
> >final drive on non-towing trucks. Maybe it's just to reduce noise....
> >I don't know. I guess what I'm asking is, If I had two Expeditions
> >that were identical except for the final drive ratio, and I drove each
> >one from LA to NYC, moderately loaded and towing nothing, what
> >difference would I notice? Thanks.
>
>
> Actually for a simple physics point of veiw, gears do make a big
> difference, like having a longer pry bar where it takes less effort to
> move the load with it. As far as what difference you would see. The
> one with taller gears will downshift more on grades and with headwinds
> and suck and oD will be about useless towing. The one with deeper gear
> will handle OD much better and towing a lot better too. As far as the
> "engineers" (and I am not picking on any one brand here because all of
> detriot does it) They gear them tall to try to squeak out make MPG is
> a rigged EPA MPG test for light duty model(the average speed for
> highway test is 48 MPH and who drive 48 MPH on highway) On heavier
> models there is the illusion that a taller gear will get beter MPG.
> Maybe with a GM 8.1 or a Ford V10 or a deisel but not with a small
> block gas motor in a big heavy truck because it does not have the
> torque to handle it effectively..
> -----------------
> The SnoMan
> www.thesnoman.com