TT Weight limits: theory and reality
There are a ton of threads here regarding the proper matching of TV and TT. Based on what I learned here, I made a very expensive decision to upgrade my brand new 1/2 ton to a 1 ton TV so that I would...
Forum Discussion
myredracer wrote:In simple terms -- the TV brakes can only generate maximum stopping force equal to the TV's hitched GVW multiplied by the coefficient of friction between tires and pavement.
That was my point - if TT brakes are only partially working, stopping distance will be increased. Along with that, higher combined weight will result in longer stopping distance. I'd rather be somewhat below the GCWR so that if the TT brakes aren't at 100%, you've got a safety margin for the TV brakes.
The TV's stopping force does not depend on the TV's GVWR -- only on the TV's GVW.
The tires and pavement don't respond to what the TV can weigh -- they only respond to what the TV does weigh.
This means that, if the coefficient of friction = 1,
a TV with GVWR = 7000# and GVW = 7000# can generate a maximum of 7000# of braking force, while
a TV with GVWR = 9000# and GVW = 7000# also can generate a maximum of 7000# of braking force.
If the GCW is 14000# and the TT is generating no braking force, the maximum deceleration will be 7000/14000 = 0.5G -- both for the TV loaded to 78% of GVWR and for the TV loaded to 100%.
One could argue that the higher GVWR would mean more robust brakes. However, the 2013 F-150 specs page 96 (9 of 15) show that Ford uses the same brakes for 8200# GVWR as for 6450# GVWR.
And, even if brakes do generate greater stopping torque, the stopping force still is limited by friction coefficient and GVW.
Ron
