Planning fuel stops for a big rig

Fuel is the part of RV trip planning people skip because it feels obvious. It isn't. A big rig can't pull into most corner gas stations, can't always turn around if the canopy is too low, and can burn through a tank faster than you'd guess with a headwind and a few climbs. Planning fuel is mostly about two numbers and one habit.

1. Work out your real range

Range is tank size times real miles per gallon. Use the MPG you actually get towing or loaded, not the brochure number, and use usable tank size (most tanks don't give you the last few gallons cleanly). For example, a 100-gallon diesel tank at 8 miles per gallon is about 800 miles on paper. A tow vehicle with a 36-gallon tank at 10 miles per gallon is about 360.

If you don't know your real MPG, start tracking it now: fill to full, reset the trip meter, and divide miles by gallons at the next full fill. A few stretches give you a number you can trust. Our guide to tracking trip costs and fuel economy covers the method.

2. Pick a reserve and stick to it

A reserve is the fuel you refuse to use. A quarter tank is a common choice for big rigs, and it's what we'd suggest if you're unsure. Go higher on remote western stretches, in winter, or when you're towing into wind. With a 25% reserve, the 800-mile diesel pusher above plans to fill by about 600 miles, and the 360-mile tow rig by about 270.

The reserve isn't for running out. It's for the station that's closed, the pump that's out of diesel, or the island your rig can't swing into.

3. Find stations a big rig can actually use

• Truck stops are the default. Big travel centers on the interstate are built for long vehicles, with wide approaches and room to pull through. Many have separate RV or auto diesel islands, so you don't have to use the high-flow truck lanes.
• Check the canopy and the exit. A low canopy or a tight lot with no pull-through is the problem at small stations. Look at the satellite view before you commit.
• Diesel isn't everywhere. In rural areas, plenty of stations carry gas only. If you run diesel, confirm it before you plan a stop.
• Fill before the empty stretches. Parts of Nevada, Utah, west Texas, and the northern plains have long gaps between stations. Fill at the last good stop even if you're above your reserve.

4. Put the stops in the plan

Once you know roughly where your reserve runs out on each drive, put a fuel stop on the route a bit before it. Treat it like any other stop: it costs time, it should fit your rig, and it's easier to decide on the couch than on the shoulder.

How RV Compass plans fuel

Add your tank size and refuel reserve to the rig profile (the reserve defaults to 25%, with 10, 15, 20, 33, and 50% as other options). The planner uses your rig's MPG to mark where each drive reaches your reserve, then suggests up to three stations near that point, with truck-stop and diesel badges and a detour estimate. One click adds a station as a fuel stop. This part is free on the web.

In Pro navigation, a fuel gauge counts down your range as you drive. You get a warning when you reach your reserve and at 50 and 25 miles of range, and the fuel sheet lists up to five stations ahead. If you stop at a planned fuel stop for a couple of minutes, the app asks if you filled up so the range resets. Fill-ups you log in the Garage feed your measured MPG, so the range math gets more honest over time.

More on the feature in fuel range that knows the truck stops, or see the full process in big-rig route planning.