...the tow limits in the US are very low compared to the rest of the world it seems.
That may be so. I’ve done a fair amount of recreational towing over the past 10+ years, and I’ve given this issue a bit of hopefully rational thought.
Without taking sides, allow me to offer the following hypothesis: The U.S. in general, and the continental U.S. in particular, presents an unusually harsh set of conditions for recreational towing due to its unique combination of location, climate, geography, speed limits, and perhaps other factors, such as the frontal area of our rather large RV's. Accordingly, U.S. tow limits may seem to be on the “low” side.
The U.S. is a large and diverse land mass covering 3.8 million miles^2, or 10 million km^2. The continental U.S. (not including Alaska or Hawaii) spans four time zones. Temperatures range from a July average high of 115 F (~46 C) in Death Valley, CA, to a January average low of -8 F (-22 C) in International Falls, MN, and perhaps worse elsewhere.
Elevations in California range from -282 ft (-86 m) in Death Valley to 14,494 ft (4,418 m) atop Mt. Whitney. And these two points are only 80 miles (~130 km) apart. :icon_eek: California alone (~164K miles^2; ~424K km^2) is larger than Norway (~149K miles^2; ~385K km^2).
For better or for worse, I decided to evaluate conditions in
Nebraska, a centrally located state, in considering this issue:
- The I-80 interstate highway (motorway) through Nebraska generally parallels 41 degrees north latitude, roughly the same as Madrid, Spain, and Rome, Italy. In comparison, Frankfurt, Germany, is at ~50 degrees north latitude; Dublin, Ireland, is at ~53 degrees north latitude; and Oslo, in southern Norway, is at ~60 degrees north latitude.
- I-80 across Nebraska is 455 miles (733 km) in length.
- The interstate speed limit in Nebraska is 75 mph (121 km/h).
- Average July daily high temperature in North Platte, Nebraska is 88 F (~31 C), and the record high temperature is 108 F (~42 C).
- The eastern side of Nebraska is ~900 ft (~275 m) above sea level, and the western side is >5,000 feet (>1,500 m) above sea level.
So, it’s possible to drive 455 miles (733 km) -- roughly the distance from London, England, across France to Bern, Switzerland -- west across Nebraska, which lies south of most of Europe, at 75 mph (121 kph) in 6 hours in 88 F (~31 C) or higher temperature while climbing >4,000 feet (~1,200 m) along the way, all while running the air conditioning in the tow vehicle.
These are demanding towing conditions, and there are more of them in the U.S.:
- I-90 through the Homestake Pass (6,329 ft) in Montana
- I-80 across Wyoming
- I-70 across the Colorado Rockies (Eisenhower Tunnel, 11,158 ft)
- I-40 west across the Texas panhandle
- I-40 east out of Albuquerque, New Mexico (Tijeras Canyon)
- I-25 in New Mexico and Colorado (Glorieta Pass, 7,500 ft; and Raton Pass, 7,834 ft)
- I-15 north out of San Bernadino, California (Cajon Pass)
- I-15 north out of Baker, California (Baker Grade)
- I-5 north of Los Angeles through the Tejon Pass, and the Grapevine
Subaru’s U.S. tow limits, as well as those from other auto manufacturers, may see low, but my experience and analysis indicates there’s probably good reason.
RV (caravan) towing conditions can be more favorable in other countries. For example, my understanding is that the maximum speed limit Norway's only motorway is 100 kph (62 mph), and the national maximum speed limit otherwise 80 kph (50 mph). Combined with generally shorter towing distances and a cooler climate, these conditions are not nearly as stressful on a tow vehicle and the driver.
My first tow vehicle was a 1986 Chevrolet Suburban with a 350 cid (5.7 L) V8. Its tow manual included two sets of limits: one for long distances in any weather at interstate speed limits, and the other for short distances in cool weather at no more than 45 mph (72 kph). I don’t remember the details, but I do remember the latter set of limits were MUCH higher than the former.
Now, where did I leave my beer? :icon_wink:
Jim / crewzer
