Inside Wealth

World's Largest Trove of Tiny Cars Goes to Auction

Lot 584_1959 BMW Isetta 'Whatta Drag'.
Source: Darin Schnabel | RM Auctions

Like many of the wealthy, Bruce Weiner likes to collect things.

The candy entrepreneur who made his fortune from Double Bubble and Razzles gum, wax lips and other confections collects radios, watches, vintage motorcycles and Volkswagens.

But his real passion in recent years has been collecting small cars. Very small cars. Over 11 years, Weiner has built the world's largest collection of "microcars" – three- and four-wheeled cars made after World War II that are the early predecessors of today's increasingly popular Smart cars, MINI Coopers and Fiat 500s.

Today and tomorrow, Weiner and RM Auctions will be selling off the collection of more than 200 cars and 300 car-related collectibles. The collection is expected to fetch more than $6 million.

(Read more: 10 Cars That Just Sold for More Than $2 Million)

Weiner said he's selling the collection as part of a broader downsizing of his lifestyle and desire to share the cars with others after spending years hunting them down.

"I'm 54 and I'm starting to simplify," he said. "I don't want my stuff to own me. "

He said that it took 11 years to build the collection. While microcars have always been the poor cousin to vintage muscle cars and exotics, they have a cult following among collectors. Many microcars were built in Europe and Asia after World War II, when money, gasoline and raw materials were scarce. In many countries, cars with three wheels didn't require a driver's license, making them more attractive.

"They are very rare," Weiner said. "And they're part of history."

Weiner said much of the joy of building the collection was "the thrill of the hunt."

Take, for example, his ordeal in buying the 1955 Kroboth Allwetter-Roller, a three-wheel convertible designed by car-design legend Gustav Korboth. Weiner heard that a prized example of the car was owned by an older man in Bavaria. Weiner traveled to the man's house every three months for three years, but the seller adamantly refused.

"He chased me off the property every time," he said. "He either met me with a shot gun or German shepherds."

(Read more: Must-Have, $1.6 Million Supercar Isn't Street Legal)

Eventually, the owner died and Weiner befriended the man's sister and brother, and convinced them to sell. The car could sell for $40,000 to $50,000 (there are no reserves in the sale).

Among the most valuable cars to be sold in the auction is a 1958 F.M.R. Tg 500 "Tiger," which could sell for more than $150,000. A modified 1959 BMW Isetta, called "Whatta Drag," could fetch $100,000. The car was commissioned by Weiner to look like a famous Hot Wheels drag-racer. It's only one of four Hot Wheels to be turned into real cars.

The smallest production car ever built will also be sold. The 1964 Peel P50 could sell for $35,000 to $40,000. The sales slogan for the three-wheeler used to be "Almost cheaper than walking!" Apparently, not anymore.