Bike Tool

Jim Walls and his bike tool. Photo by James Kellar


Thirteen years elapsed between the day Jim Walls built his prototype Cobra Tire Tool and the day the tool hit the market. It’s not that Walls was distracted or lost interest in the little tool that makes it easy to fix a flat on a bicycle. “I just couldn’t believe that it wasn’t already out there,” he says. But when years of exhaustive international searches came up empty, Walls says he knew he “had to pursue” mass production of the Cobra.

He found a ready audience in cycling-mad Bloomington. The Cobra debuted at the 2010 Hilly Hundred, where riders snapped up more than 250 of the three-inch tools. In its first year, Walls sold more than 1,000 to cyclists from Indiana to Britain to Australia.

Walls is not an avid bike rider, but he knows tires. His family owned a tire franchise for many years and sold and fixed tires “for everything—cars, trucks, farm equipment, huge off-road vehicles used in mining.” All could fit on a modern tire-changing machine, but a bicycle tire was still pried off the rim with levers “in a hundred-year-old method that goes back to the inception of pneumatic tires,” Walls says. “Changing a bike tire can be very tough. I thought, ‘How can we take the process of the tire-changing machine that spins the tire off and apply it to bikes?’”

In just 30 minutes, Walls designed a tire tool, and then took another 30 minutes to fashion the prototype Cobra—it looks like a snake about to strike—from a small piece of metal. But would it work? “Taking one of my kid’s bikes, I let the air out of the tire and inserted the tool. To my amazement, the tire came off the rim faster and easier than I would have imagined.”

And then 13 years went by. Finally convinced that his invention was unique, Walls sought a manufacturer for the Cobra, which is produced at PRD, Inc. in Springville, Indiana. It weighs just half an ounce, is made of durable nylon and fiberglass, and won’t scratch the bicycle frame or tire rim. The online magazine Road Bike Rider called the Cobra a “cool tool” and, at $5.99, “super-affordable.”

For more information, including an instructional video, go to