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Depending on the truck configuration, you could be looking at a difference between 8,200 lbs vs. 9,200 lbs max trailer weight. From the math perspective, that's just over a 12% increase in weight. Taller gears (numerically lower) lower you overall or effective gear ratio. This, in turn, increases the strain on the transmission. Strain can become evident through additional wear & tear or outright failure of some component on the transmission.
While I am sure that Ford's mechanical engineers have underrated many aspects of any given vehicle, I see no reason to test those limits...especially given the size of some repair bills. Besides, if you are towing/hauling that close to the published vehicle limitations, it may be a good sign that it is time to look at a more capable vehicle (Ranger -> F-150 -> F-250 -> etc.). Besides providing higher payload & towing ratings, you will also gain a larger, more capable vehicle for the work load that you are subjecting the vehicle to....and that makes the roads safer for all of us.
Depending on the truck configuration, you could be looking at a difference between 8,200 lbs vs. 9,200 lbs max trailer weight. From the math perspective, that's just over a 12% increase in weight. Taller gears (numerically lower) lower you overall or effective gear ratio. This, in turn, increases the strain on the transmission. Strain can become evident through additional wear & tear or outright failure of some component on the transmission.
While I am sure that Ford's mechanical engineers have underrated many aspects of any given vehicle, I see no reason to test those limits...especially given the size of some repair bills. Besides, if you are towing/hauling that close to the published vehicle limitations, it may be a good sign that it is time to look at a more capable vehicle (Ranger -> F-150 -> F-250 -> etc.). Besides providing higher payload & towing ratings, you will also gain a larger, more capable vehicle for the work load that you are subjecting the vehicle to....and that makes the roads safer for all of us.
Just my opinion...
Thanks for the explaination! I will be checking the sticker on my door when I get back home! I'm hoping that being an FX4 with a factory class IV hitch, it has the 3.73...
Reguardless, my trailer weight loaded is in the 6,500 lbs range.
Fx4 Dont come standard w/3.73's.I road tested two of them today,Screw and a Scab and the Screw had 3.55 and the Scab had 3.73.Both had 20" wheels and Tow package w/leather.
All cab configurations with P275/65Rx18 OWL A/T tires come with 3.73 limited-slip gears
OR
SuperCab & SuperCrew configurations with P275/55R20 OWL A/T tires come with 3.55 limited-slip gears
Those are the standards. Options can obviously change them.
At first glance the tires seem pretty different, but in all actuality, they are remarkably similar. Granted, each manufacturer can measure their tires a bit differently, but after converting the metric tire sizes over, one can see how similarly sized the factory tires are to each other:
Metric tire size - Height x Width x Sidewall height
P275/65Rx18 - 32.1" x 10.8" x 7"
P275/55R20 - 31.9" x 10.8" x 5.9"
I figured that I would mention it because the motor companies generally only change the gears based on tire size. A taller tire will get lower gears (higher numerically) in order to keep the overall, or effective, gear ratio of the vehicle within a certain range set forth by their fleet of mechanical engineers. This is not the case here. Not that 3.73 to 3.55 is much of a gear change, but it is kind of curious why they would change the "standard" gears between a couple of tires that are very similar in height & weight (per Tire Rack's tire specs).
Side note: The "standard" gears often get changed with optional payload packages, but as we are talking about what comes standard on the vehicle, I left the whole payload vs. gearing discussion out of the equation.
Last edited by Deluxe05; Feb 17, 2008 at 06:03 AM.
Another thing that is different between the FX4 and the Lariat is the audio and heater controls in the steering wheel. These contols are standard on the Lariat. Don't know about 2008 but in 2007 the only way to get this option in the FX4 was by purchasing the FX4 Luxury Package.
That package includes:
Heated seats with power adjustable pedals
Self dimming rear view mirror
Electronic Automatic Temperature Control (AETC)
Black Leather Steering wheel with Audio and Climate controls
Captains chairs with flo thru console
Yeah, there are a number of differences between the FX4 & Lariat. The FX4 fits between XLT & Lariat, and each trim level builds on the previous trim level.
XL is, obviously, the entry level
STX contains all XL content plus a couple items
XLT contains all STX content plus a couple items
FX4 contains all XLT content plus a couple items
and, Lariat contains all FX4 content plus a couple items
While this thread is really biased towards what the standard features were in the FX4 trim level, the Lariat includes the following (in addition to all previous trim levels):
Chrome bumpers
Chrome grill surround
Driver side self-dimming mirror
"honeycomb" grill insert
Power, heated side mirrors w/external mirror mounted turn signal indicators
Pueblo Gold front & rear step bumpers (w/two-tone paint)
Additional steering wheel controls (the aforementioned audio & climate controls)
Color-coordinated floor mats
Electronic Automatic Temperature Control (EATC)
Leather-trimmed 40/20/40 front seat w/manual driver & passenger lumbar
The FX4 Luxury Package was/is a great way to get many of these standard Lariat trim items into an FX4 level truck. On a related note, this package does require you to go with the black, leather-trimmed Captain's chairs & the power driver seat options.
EDIT: Hmm...looks like I posted while you were editting your post!!
At first glance the tires seem pretty different, but in all actuality, they are remarkably similar. Granted, each manufacturer can measure their tires a bit differently, but after converting the metric tire sizes over, one can see how similarly sized the factory tires are to each other:
Metric tire size - Height x Width x Sidewall height
P275/65Rx18 - 32.1" x 10.8" x 7"
P275/55R20 - 31.9" x 10.8" x 5.9"
I figured that I would mention it because the motor companies generally only change the gears based on tire size. A taller tire will get lower gears (higher numerically) in order to keep the overall, or effective, gear ratio of the vehicle within a certain range set forth by their fleet of mechanical engineers. This is not the case here. Not that 3.73 to 3.55 is much of a gear change, but it is kind of curious why they would change the "standard" gears between a couple of tires that are very similar in height & weight (per Tire Rack's tire specs).
Side note: The "standard" gears often get changed with optional payload packages, but as we are talking about what comes standard on the vehicle, I left the whole payload vs. gearing discussion out of the equation.
A P275/65Rx18 has a taller sidewall as you point out than the P275/55R20 would, with same width and overall height. It thus has a greater interior volume, holds more cubic inches of air under any given pressure. I'll look at Tire Rack later ... but my guess is the P275/65Rx18 size has a higher load rating in pounds than the P275/55R20 does.
Also, with taller sidewalls, more forgiving of pavement defects, etc when loaded heavily, thus imparting softer shocks to the truck.
Just guessing as to why one gets higher gearing and greater tow rating.
I have an 07 FX4 black on black with heated front seats sunroof only thing it didn't have was the trip computer that gives you distance to empty or GPM