[RockyMtnRay]

Originally Posted by stressalert

Thank you so very much!! This definitely makes me feel better! If I want to tow in the mountains, are there rental trucks I could use to take the abuse? (maybe not, since I would need to install them with electric brakes.)

Rental trucks for mountain towing???? I don't think so...partly for the reason you specified (lack of brake controllers), partly because there's very little to no demand (at least 99% of folks who tow want to use their own tow vehicle), and partly because any rental company that did a thorough cost analysis would have to price its offerings so high (due to probable abuse) that hardly anyone would be willing to pay the daily rates. Towing and tow vehicles are a very specialized market...about the only generalized RVing market that supports rentals are the mid-size "Class C" rentals (e.g. Cruise Americia, RV4Rent, etc.)

If you want to do mountain towing in a regular or semi-regular basis, you simply have to upgrade to a V8 powered tow vehicle (with at least 300 ft-lbs of torque (at 3400 RPM or less) and 3.73 or lower (numerically higher) axles.

As point of reference, my Toyota Tundra came from the factory with a 4.7L V8 that produced 315 ft-lbs of torque at 3400 RPM and had 3.91 axles. I found its high altitude towing performance of my TM2720SL (loaded weight around 3700 lbs) to be just "adequate"...frequent downshifts to 2nd gear were needed to stay with traffic when crossing Colorado's high passes (over 11,000 feet above sea level) on steep grades (over 6%). So I spent around $3000 modifying the truck (headers, exhaust) to get around 350 ft-lbs of torque out of the engine and changed to lower (4.30) gears) for even more torque multiplication. I can now tow my trailer over the high passes with ease.