skipnchar wrote:
The so called 80% rule is complete nonsense. The truck is perfectly capable of towing 100% of its ACTUAL rating.
I don't agree, I believe you should stick to the 80% rule. It's not about if the truck has the power, it's about stressing the truck and damaging it.
The 80% rule takes into account the travel trailer attributes that affect towing. The larger than recommended Frontal Surface Area and heavier than normal tongue weights that go against the trucks payload.
My F150 manual states this:
Note: When taking into consideration trailer frontal area, ensure not to exceed:
• Base vehicle frontal area without the Trailer Tow Package or the
Heavy Payload Package.
• 60 ft2 (5.57 m2) with the Trailer Tow Package or the Heavy Payload
Package.
My frontal surface area without the air conditioner height included, is 77 sq ft. Well above the 60 sq ft that's associated with the GCWR. The tow rating is really only a number derived by a base truck. GCWR is really the truck spec that needs to be followed. So that 80% rule takes that into account as well. My truck has a 15,100 lbs GCWR. 15100 - my trucks weight of 5768 lbs - driver = 9090 lbs. 9090 lbs minus additional weight of family and gear (558 lbs) = 8532 lbs . So that's a 77 sq ft frontal surface area with a true tow rating of only 8532 lbs. 80% of Ford's 9300 lbs tow rating is 7440 lbs.
My payload is 1582 lbs without family, gear, bed accessories. After bed accessories, all of us and gear (800 lbs), we have 752 lbs of payload left for tongue weight. tongue weight is normally around 13% for a dual axle travel trailer and the distribution hitch usually distribute about 80% of the tongue weight (including the hitches own weight) to the trucks axles (payload).
So 752 lbs left. 752/.8 = 940 lbs hitch weight. 940/.13 = 7231 lbs loaded trailer.
So here's the deal. I have a true tow rating of 8532 lbs, then I have a larger frontal surface area, than the recommended surface area for that tow rating. So that obviously lowers the tow rating.
Now my payload limits my towing to 7231 lbs. 80% of 9300 lbs is 7440 lbs.
Seems that 80% rule is "RIGHT ON".
Of course ignore it and have possible transmission, differential, or axle damage, EVEN IF your engine is strong enough to pull it.
