Well, I took on more weight than I wanted to. We filled the trailer to the brim. I estimate it ate 350-400 pounds, plus the 900 pound trailer weight.
How did the smart take it? Surprisingly well. I couldn’t be in fifth gear on ground that wasn’t flat but other than that the car pulled extremely well. My biggest concern was starting on hills. The transmission dragged the clutch 3x as far as it normally would. I remedied that by coasting to the lights on hills so I wouldn’t have to actually stop. Just because I could I drove it to Chicago, then Milwaukee, and back. Grand total of a few hundred miles.
The tow vehicle:
Tucker is a 2012 smart fortwo with 132,000 miles. He has hauled a variety of loads, from 7+ feet tall people to 600 pound passengers, all with ease. But he hasn’t ever towed anything before.
A 5x8 enclosed trailer from U-Haul. Unloaded weight 900 pounds, tongue weight about 45-ish pounds. Loaded up with my stuff: 1,300 pounds and about 140 pounds tongue weight.
Was glacial. It took about 45 seconds to reach 60 mph at 75% throttle. I never floored it because I was afraid to push it hard. This is on par with our Expedition doing the same with our travel trailer.
Was extremely soft. Seems the extra weight - while making the car bouncy - made the suspension soak up the bumps so much better.
Didn’t seem to take a huge hit. It tracked straight even in crosswinds. No wobble, no oscillation, even carved highway exits.
Top speed in 5th gear was around 65 provided flat ground. Top speed in 4th gear regardless of road grade was theoretically 80. There was so much torque in 4th gear that had I tried to, I could redline it. I didn’t, but the car wasn’t afraid to do it.
My cheap rockauto front brakes and the 132k factory drums in the back didn’t seem phased by the extra weight.
With an empty trailer I observed about 40 mpg overall. Loaded, that number dropped to roughly 33-35 mpg.
The problem came from being loaded in 5th gear. Instead of giving the car a 6th gear like in the previous and next generations, smart deleted the 6th gear and made 5th gear really long. So the torque really wasn’t there to maintain speed on uphill sections. The car’s “sweet spot” was 50 mph with the loaded trailer.
My verdict: A smart can definitely tow a heavy trailer very well. Perhaps ironically, with a trailer in tow it thrives on the highway and sucks in the city where the clutch keeps spinning.