Towing capacity and its effect on the Rivian R1T’s range will be an important point for some buyers. They do know how much the Rivian truck can tow, 11,000 pounds or 7,700 pounds for the R1S SUV, but they don’t know what that has on the vehicle’s real world range.

Well, we now have part of the answer to that question courtesy of a photo that surfaced on the Rivian Forums. The photo shows an R1T’s predicted range, speed and other parameters while the truck was towing a Ford Mustang on a flatbed (open air) trailer. Combined, their total weight is 14,260 pounds, according to McMoo, the forum member who posted the photo.

The big news here is that with 37 percent left in the battery, traveling at 73 mph, the vehicle only showed a projected range of 44 miles (71 km). With 100 percent in the battery, a vehicle with the smaller 135 kWh battery would only go around 118 miles (189 km), or 157 miles (252 km) with the larger 180 kWh pack.

It’s worth noting that since it was being driven at 73 mph, this surely had an impact on the range projection. Had the vehicle been driven slightly slower, at around the 60 - 62 mph (96 - 100 km/h) mark, then the estimated range would surely have been higher.

For reference, the R1T with the 180 kWh battery has an EPA range of 314 miles (505 km), although it has exceeded that by a few miles in independent range tests. The R1S SUV achieved a slightly better 316 miles (508 km).

Rivian says that towing the maximum allowed 11,000 pounds with the R1T will drop the range by about half and even though the trailer and Ford Mustang didn’t quite add up to that, the manufacturer’s estimate seems to be accurate.

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