With schooling in mechanical/aeronautical engineering, he rode a modified skinny tire ten speed bicycle up and down Mt Tamalpais, valuing nimbleness and gear selection (aided by toeclips—when platform pedals were the norm) over the ungainly 1930s ballooners then in vogue. When Ukai came out with wide 26" aluminum rims, he designed and built his first mountain bike, completing it in 1979. It was an experiment with lightweight heat treated 6061 aluminum tubing and purpose specific brakes, forks and hubs of his design.
At a time when the first custom mountain bikes were made of steel tubing with traditional components, this bike, now in the Crested Butte Mountain Bike Hall of Fame, was controversial.
Along with frame builder Steve Potts and his helper Mark Slate, Cunningham co-founded Wilderness Trail Bikes or WTB. Cunningham and Potts were forced out of WTB in 2002 at the urging of WTB's CEO, Patrick Seidler. Seidler, a lawyer by trade had them both agree to and sign non-disclosure agreements, AKA "Gag-orders". Because of this, Cunningham and Potts will not talk about why they left WTB. Cunningham and his wife Jacquie Phelan are charter inductees to Crested Butte's Mountain Bike Hall of Fame.
The Cunninghams, being in the Air Force, lived in Alabama, Virginia, Japan and San Diego, ultimately settling in Mill Valley on Mt Tamalpais, in Marin County. His father, Lt. Colonel Bruce Cunningham, was a WWII and Korean War fighter pilot who won the Thompson Trophy in 1949, the only year military jets (F-86) competed. His mother, Carol is a book artist whose imprint Sunflower Press is found in several museum collections, and is sought after worldwide. In his twenties, Charlie studied nutrition, water quality, and chemistry as well as engineering. By age twenty five he recognized that automobile use in the USA is largely wasteful, polluting and socially ruinous. His solution: bicycles. His would not rust or wear out, requiring little maintenance. This last would prove most valuable for racers in multi-day stage races.
Life as an inventor
In the early 1980s, Cunningham made significant contributions to the modern mountain bike:
- welded & heat treated aluminum mountain bike frames
- sloping top tubes on mountain and road frames*
- tubular-style fork crowns
- 135 mm zero-dish rear wheel for mountain bikes (now the standard)
- identifying the fundamental tread design principles needed for good-performing mountain bike tires. Co-designed Ground Control, the first tire incorporating these principles.
- invented the Grease Guard Bearing System that allows bicyclists to completely replace with clean grease in seconds the dirty grease that always gets into bicycle bearings...thus extending component life and saving significant time and money spent overhauling and/or replacing parts. Grease Guard's effect on component longevity conflicted with the bike industry's needs. The industry requires that bike parts wear out, thus necessitating replacement.
- the Roller Cam Brake. The brake arms, the pivot mounting location, and the linkage combined to eliminate flex in the fork blades and frame stays. Ultimately, the cam was replaced with the Lever Link, resulting in a brake that Cunningham believes is his best rim brake.
Cunningham's Roller Cam brake also featured the linear spring he invented, now used on almost all V-Brakes today.
Cunningham raced only one year: in 1984, placing tenth overall at the NORBA championships in Nederland, Colorado. At thirty-six years old, he was made National Vet Champion.
Cunningham built a total of 187 aluminum bicycles (the Indian, the Racer, and the Wombat for smaller people) between 1979–1992. They were guaranteed for life, and cost about six times as much as custom (steel) bikes. They are considered collector's items, but many are still regularly ridden.
At present, he is a freelance inventor contributing to environmentally sustainable projects.
- "Charlie Cunningham". The Mountain Bike Hall of Fame. Retrieved 30 December 2010.