FORD F-150 AXLE RATIO CHOICE.

My new trailer (Keystone 26RBS) weighs only 6600 lbs + cargo.
I?m about to order a 2021 Ford F-150 equipped as follows:
V6 3.5 engine
Standard (not Max) Trailer Towing Package.
This truck has a 10-speed auto transmission, and can tow 10,500 lbs and the same 16,200 lbs GCWR with EITHER the 3.31 or 3.55 AXLE RATIO,  according to Ford.
I was thinking about ordering the 3.31 axle ratio for fuel economy on flat highways, and pulling the trailer in 9th or 8th gear if necessary, which would raise the axle ratio as needed.
Can anyone help with this decision?
Thanks.
Pierre

You WILL want Maxtow...  Trust me, I have one.  You also will want the 3.55 gears. Maxtow adds a few features that std unit does not.  One is the 36 gal gas tank, a must have with trailer, better suspension, oil cooler etc.  I get 24 mpg on hwy without trailer, what else could you ask for.  You also will need to pay attention to what you order.  If you order a XLT or higher, with the leakroof (aka moonroof), and rear step, Your payload numbers will suffer.  Most guys at the Dealer are clueless about payload and ordering.  Your Keystone is at the borderline higher end of the std 3.5 with maxtow.  If you go less, you will be very disappointed.  I spent months researching, and I'm on a couple Ford truck Forums, and I too special ordered my 2020 Lariat maxtow.  Towing 10,500 lbs is marketing hype.  If it's flat steel maybe.  The longer > 25' travel trailer, wind dynamics, push these F150 toy trucks around. I even kinda wish I bought the longer bed, but didn't.

ps: good for you doing your homework.  Stay away from RV salespeople and Dealer Car lots for advise, finding knowledgeable people at either is rare.  Spend some time on a few Ford F150 Forums, other owners will give you advise as well.

Bellavance said:

My new trailer (Keystone 26RBS) weighs only 6600 lbs + cargo.

This truck has a 10-speed auto transmission, and can tow 10,500 lbs and the same 16,200 lbs GCWR with EITHER the 3.31 or 3.55 AXLE RATIO,  according to Ford.

Click to expand...

Hi

Maybe I'm missing something, but if I understand correctly, then I think you have either have too much trailer or too little truck.  I read your post to say that the trailer is 6600 lbs, unloaded - since you say "plus cargo".  Conservatively, depending on just how you travel and plan to use the TT, your cargo can easily add 1500+ lbs to the base trailer weight.  Just 80 gallons of liquid, which could be combination of fresh water and wastewater at times, alone will add 666 lbs.  A hitch will add another 100 lbs and change.  Tools, chairs, grill, cookware, dishes, towels, bedding, food, clothing etc. can easily add another 1000 lbs. or more. That puts your trailer weight at ~8360 lbs.  And since you should also count on a safety factor of 10-12% of the trailer GVWR (not provided) which I'm going to guess is likely somewhere around 8400 lbs, you;re now pushing a working number of ~9200 lbs.

While this is below the max tow capacity stated by Ford, the problem is with your CGVWR stated as 16,200 lbs.  That means the truck and its payload cannot be over 7,000 lbs, again with no safety margin.  My F250 weighs in at 7500 lbs with a 3400 lb payload, so the F150 without upgrades cold be lower, but I think you're way too close to the edge to tow this trailer with a standard F150.

If you cruise YouTube you'll find lots of towing tests done with F150s, and just how much trailer they can actually, safely maneuver and that upper number is about 5000-5500 lbs.  Can you pull this set up, Yes, you can.  But can you maneuver in wind, slick roads, rutted highways, truck passing you, etc.  That will become challenging I think, as will climbing hills or mts.  Lots of truck numbers are based on pulling a flatbed trailer that has minimal wind resistance and a completely level load.

A 6600 lbs empty trailer is not a lightweight.  If I'm off base here, then ignore the info.  If not, I think I'd recommend you ignore what dealers are telling you - especially the truck salesperson, and look at all your numbers considering actual travel weights.  This means looking at truck payload (which includes 12-15% of actual travel loaded weight), and truck weight, and loaded trailer wt. with some water on board.  This number cannot exceed the CGVWR.  Likewise, your truck payload cannot exceed the truck+ cargo, + ~12% of trailer hitch weight. 


You will definitely need the MAX tow upgrade features.  IMO, if I read things right, you won't be happy with an F150 towing this set-up.

Linda
BTW - Not a member of the towing police!

Walk around a Ford dealer lot and read the yellow stickers on the driver door latch post. It reflects the actual weight of the truck as built, and therefore, subtracting from truck GVWR gives THAT trucks payload. Every option on the truck reduces its payload while increasing the weight of the truck which, in turn reduces the weight it can safely tow (or stop).