I've entered the new world of 19.5" tires. I purchased a 2003 Coachmen 31' motorhome with 225/70R-19.5 LR-G tires.
The previous owner had all 6 inflated to the maximum pressure listed on the sidewalls, and not surprisingly, the motorhome rode and handled like the tires were full of concrete.
These tires aren't OEM, the last owner replaced them in 2010, with tires with 2010 date codes.
So, after a visit to the local grain elevator, I was shown how to turn on the exterior scale display during non-business hours.
I weighted it empty (3 people inside), and it was front axle 5200#, rear axle 8400#. This was with about 25 gallons of gas (75 gallon capacity), and about 20 gallons of water (100 gallon capacity) on board.
So...I unloaded the old travel trailer, and carried everything into the motorhome, and headed for the elevator for a "loaded" weight.
With the same three people inside, it weighed 5380# on the front axle, and 8800# on the rear axle.
I don't expect to ever carry over 50 gallons (1/2 tank) of water while travelling, so that would add roughly 250 pounds to the rear axle weight, and a full tank of gas would add another 300 pounds of rear axle weight.
So, to give an additional margin, I think we could reasonably bump the rear axle weight up to a max of 9800#, and increase the front axle to a max of 5700#.
Looking at the BFGoodrich spec sheet for the tires (model ST230), it shows:
65psi = 5510# single, 10400# dual
70psi = 5790# single, 10880# dual
75psi = 6080# single, 11440# dual
As an alternative to the previous owner's strategy, I've already tried 70psi in all six, and the difference in the ride quality and handling is like night and day.
According to the BFG specs (if I'm reading them correctly), I'm fine at 70psi. If anything, I may go up to 75psi on the fronts for some wiggle room.
A question: Both the water tank and the gas tank are located *behind* (aft of) the rear axle. In theory, shouldn't those, since they are located behind the rear axle, help to effectively reduce some of the weight load on the front axle, as I add water and gas to them?
The previous owner had all 6 inflated to the maximum pressure listed on the sidewalls, and not surprisingly, the motorhome rode and handled like the tires were full of concrete.
These tires aren't OEM, the last owner replaced them in 2010, with tires with 2010 date codes.
So, after a visit to the local grain elevator, I was shown how to turn on the exterior scale display during non-business hours.
I weighted it empty (3 people inside), and it was front axle 5200#, rear axle 8400#. This was with about 25 gallons of gas (75 gallon capacity), and about 20 gallons of water (100 gallon capacity) on board.
So...I unloaded the old travel trailer, and carried everything into the motorhome, and headed for the elevator for a "loaded" weight.
With the same three people inside, it weighed 5380# on the front axle, and 8800# on the rear axle.
I don't expect to ever carry over 50 gallons (1/2 tank) of water while travelling, so that would add roughly 250 pounds to the rear axle weight, and a full tank of gas would add another 300 pounds of rear axle weight.
So, to give an additional margin, I think we could reasonably bump the rear axle weight up to a max of 9800#, and increase the front axle to a max of 5700#.
Looking at the BFGoodrich spec sheet for the tires (model ST230), it shows:
65psi = 5510# single, 10400# dual
70psi = 5790# single, 10880# dual
75psi = 6080# single, 11440# dual
As an alternative to the previous owner's strategy, I've already tried 70psi in all six, and the difference in the ride quality and handling is like night and day.
According to the BFG specs (if I'm reading them correctly), I'm fine at 70psi. If anything, I may go up to 75psi on the fronts for some wiggle room.
A question: Both the water tank and the gas tank are located *behind* (aft of) the rear axle. In theory, shouldn't those, since they are located behind the rear axle, help to effectively reduce some of the weight load on the front axle, as I add water and gas to them?