1975 Rupp RMX-125

Model Information

Rupp Industries is one of the most interesting stories in the history of US power sports. In 1959 Mickey Rupp started Rupp Manufacturing in a small 3000 sq. ft. facility in Mansfield, OH building go karts. The following year he expanded into mini-bikes, then started designing their first snowmobile in 1964.

By 1970, Rupp employed over 400 staff in an 180,000 sq. ft. complex and produced over 35,000 snowmobiles a year. By comparison, in 2011 the total combined snowmobile sales in the US were approximately 50,000 units. Apparently Rupp may have expanded too quickly, as a few years of weak snow fall combined with a massive influx of Japanese mini-bikes pushed the company towards bankruptcy.

To my knowledge, Rupp tried to ride the explosive growth in the 125 motocross bike market with the introduction of the RMX 125 as a 1973/1974 model. I think the 1973 and 1974 models were one and the same. 1975 was the final model year of the RMX 125 and differed only in the addition of adjustable lower shock mounts.

The sales literature stated “A factory works machine available to the public”. I’m not aware of any magazine tests on these bikes, but they were equipped with some pretty nice componentry. One of the more interesting aspects of the RMX was the fact that Rupp commissioned ALCOA (Aluminum Company of America) to manufacture the aluminum hubs and triple clamps; definitely ahead of their time in 1973!

Other RMX components included; Akront rims with Metzler tires as well as Showa forks and Girling shocks. For some reason I always thought of the Tecumseh powered Rupp mini-bikes as poorly designed. But the quality of craftsmanship of the Rupp RMX 125 is very impressive. My guess is that they only manufactured a few hundred of these bikes. I’ve also heard that Rupp produced an RMX 100 which was essentially the exact same bike with a sleeved down motor and an automatic RMX 125 of which only a handful were ever produced. I’ve never seen either of them.

Rupp Industries went out of business in 1978, but launched Rupp Marine in 1979 when Mickey Rupp decided to offer “the finest outriggers you can buy for sport fishing”. I hope that someday somebody writes a book about Mickey Rupp to document an amazing American story that more people should know about.

1975 Rupp RMX-125

I purchased this bike from Nick Rowe who lives up in Michigan. Nick grew up riding Rupp’s because his father owned the local Rupp dealership, as a consequence he knows a lot about the brand. Nick told me a great story about the time his father brought him to the Rupp factory in Ohio in 1972. While they were there, on the dirt track next to the factory he saw them riding a bike that was bigger than any Rupp he had ever seen before. When they went to check it out, they got to see them testing an RMX-125 prototype, almost two years before it was available to the public!