Forty days of winter testing on the Mesaba Avenue climb

Mesaba Avenue rises about 400 feet in a little over a mile, and in January it is packed snow over ice for weeks at a time. If a cargo bike can climb it at 7 AM with a full load and come back down under control, it can handle almost any street in the country.

From the first hard freeze until the thaw, four prototypes did the climb every morning, loaded to between 220 and 330 pounds. We logged battery temperature, motor current and brake rotor temperature on every run.

What froze

• The original charge port cover: it iced shut twice. The new one has a silicone hinge and a drain channel.
• Grease in the internal hub thickened below −10°F, so shifts got slow. We switched to a low-temperature grease rated to −40°F.
• One rider’s phone, in a handlebar mount. That one is not our fault.

What held

The frame, the belt and the brakes. The 203 mm rotors never faded on the descent, even with a kid seat and groceries on the back. The belt drive shrugged off slush that would have packed a chain solid.

“By February I stopped thinking about the hill. That is the whole point.”

The biggest change came from the battery data: below about 20°F the cells gave noticeably less range. That led to the heated battery sleeve, which we wrote about in October.