Heavy-Haul Trailers Adjustments update v1.9 for American Truck Simulator. Heavy-haul route maps also updated.

  • cotton harvester cargo name updated to show correct name in game
  • double tridem with booster (3+1) now accepts heavier cargos, heavy bulldozer and scraper

Get the file and review my guide at Heavy-Haul Trailers page. To update, download the new file and overwrite the old in your mods folder.


(updated 13 March with corrections)

Considering the 90-foot length limit in New Mexico (longer than 90 feet requires a pilot vehicle), I decided to increase the weight-limit on the 3+1 trailer to allow the heavy bulldozer and scraper. All currently available 8x4 (or 8x6) day cabs with 3+1 meet the 90-foot limit. A 6x4 cannot handle the weight of a scraper or heavy bulldozer, so an 8x4 or 8x6 is a must. This weight-limit change means in Washington State many 8x4 sleeper cabs with 3+1 may exceed the weight limit on green roads–recommend using 8x6 day cab when hauling heavy bulldozer or scraper. Outside of New Mexico and Washington any 8x6 sleeper hauling scraper may travel blue or gray roads. See the heavy-haul route maps for weight limits on colored routes and roads with length limits. Below I created a diagram to show how close some trucks make it within the 90-foot limit.

ATS 3 1 Len

The diagram above shows four trucks, two 8x4s and two tri-drives, all with the 3+1 lowboy as close to same scale as I could make them from in-game screen captures. Let us pretend we can move the 5th wheel forward so that the kingpin sits nearly over the center axle. The green lines show 90 feet from back-to-front where the front line adjusted as if the 5th wheel moved forward. Remember these cargo-and-trailer combinations made possible by my modification, Heavy-Haul Trailers Adjustments intended to allow heavy cargo when using 8x4 or 8x6 truck.

For your review the lengths where wheelbase is distance from front axle to rear-most axle:

  • 3+1 lowboy length = 66 feet (end-to-end)
  • (1) Peterbilt 389 sleeper 8x4 wheelbase = 28 feet
  • (2) Western Star 49X SBA 48-inch sleeper tri-drive wheelbase = 27 feet and 1 inch
  • (3) Kenworth W900 day cab 8x4 wheelbase = 25 feet and four inches
  • (4) Western Star 49X SFA day cab tri-drive wheelbase = 23 feet and 2 inches

For reference the distance between drive axles is 4 feet. Also, the Lonestar sleeper 8x4 (not pictured) wheelbase is 27 feet and five inches.

Currently the Lonestar 8x4 sleeper cab is the shortest 8x4 sleeper cab available in game with the Peterbilt 389 8x4 sleeper (truck 1) about a half-foot longer (to front bumper). Assuming we can move the 5th wheel close to the middle axle (too far forward and the lowboy would need a longer neck) the 389 8x4 sleeper truck (1) at 92 feet misses the 90-foot limit for travel through New Mexico without a pilot vehicle. The Lonestar (not pictured) even closer at a foot-and-half over the limit. The Western Star 49X sleeper tri-drive (2) is longer still making it difficult to meet the limit. The day cabs (3 and 4) easily meet the 90-foot limit where the 49X (4) with 3+1 lowboy is about 87 feet in length with 5th wheel moved forward (89 feet with 5th wheel positioned as pictured).

Notice the Western Star 49X 48-inch tri-drive (truck 2) has the same chassis length as the 49X 72-inch tri-drive (or 8x4). If the 48-inch chassis was 2 feet shorter it could nearly make the 90-foot limit.

Washington State limits tridem axle-group to 53000 pounds (green routes shown on the route map) which will restrict some 8x4 sleepers from hauling the heavy bulldozer and scraper with a 3+1 lowboy. In the diagram above, the Western Star 49X sleeper tri-drive (2) hauling the scraper has a 138410 GVW when fully fueled. By my estimate the drive-axle group at 54250 pounds (yellow text) exceeds Washington’s limit by over 1000 pounds. Going with an 8x4 saves 1250 pounds so it might just make it depending on how the load is distributed and where we adjust the 5th wheel.


a motel beside the truck stop parking lot near Twin Falls

Normally I drive my 49X day cab within a few hundred miles of my garage in Portland, Oregon, usually doing one-to-four jobs per day. Most nights I return home, and sometimes run an overnight out-and-back trip. So, my day cab spends most of its time in Oregon, Washington, and western Idaho. I decided to do a cross-country heavy-haul to Texas. I hauled a heavy bulldozer from Salem, Oregon to Corpus Christi, Texas using Western Star 49X tri-drive–a day cab, of course, to meet the New Mexico length limit. Planning the route included staying at motels, the first near Twin Falls, Idaho and the second just south of Cortez, Colorado. Texas is a big state, and luckily there are plenty of motels adjacent to truck stops. My heavy-haul route maps denotes sleep zones by type: motel, truck stop with motel, rest area, or parking/picnic area making planning a trip easier.

ATS HHTripCortezRefuel

trailer and cargo left behind in background as I refuel

ATS HHTripHwyResp

I spotted an accident in New Mexico


my destination in Corpus Christi