The following calculation is designed to show torque available for initial acceleration (the ability to start a load on a hill) and hill climbing. The people at Can AM RV suggest a value of 5 for serious hill work and at least a value of 7.
The following is the torque calculation for our tow vehicle:
1. Max available torque: 162 ft-lbs
2. First Gear Ratio: 3.53
3. Final Drive Ratio: 4.76
4. Tow Tire Radius: 1.2 ft
5. Tow Vehicle + Trailer Wt: 6400 lbs
6. Lbs per Ft-lb of Torque: 3.1 lbs of weight
per ft-lb of torque
To get the lbs per foot-pound of torque you do the following
1. x 2. x 3. / 4. divide the result of this into the combined weight
(5) of the tow vehicle and trailer = 6.
According to Can RV a value of 7 is acceptable and 5 great for mountains. The number for our tow vehicle came out surprising low which makes me suspicious. Any of you scientific types, please check my calculation
Since we plan to get a new tow vehicle in a couple of years I calculated the value for a number of different vehicles. It's an interesting exercise. As Andy Can AM suggests in his post though some larger vehicles have more torque, they also often weigh a lot and that reduces the available torque for the trailer load.
To prepare this article I slowly, really slowly, re-read the Can AM article I posted yesterday. There is tons of very good information in that article. When I get back to Ontario I intend to visit their store.