final drive ratio, gas mileage, other wear

External Since: Dec 12, 2005 Posts: 8

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.

External Since: Dec 12, 2005 Posts: 8

SnoMan wrote:
> On 2 Aug 2006 10:09:07 -0700, rbarzel.DeleteThis@gmail.com 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.