Outokumpu’s exhibition booth at Scandinavia’s largest subcontractor trade show Elmia could hardly have been more appealing: the crowd catcher was a prototype racing motorcycle by Highland Group of Sweden, custom-designed and manufactured with the help of Outokumpu using high-strength grades of stainless steel.

The stainless motorcycle, named Highland 450cc Supermoto, has turned eyes elsewhere. Ridden by Martin Lind of Sweden, it finished second in the Swedish Supermoto 2008 championship and has scored a number of Supermoto wins in the United States.

Supermoto is a combination of motocross and road racing, where the racing course alternates between a racing track and a dirt section in the infield. The motorcycles combine road-racing and off-road features. Compared to normal motorcycle racing, the tracks are short and twisty and incorporate high jumps, which puts the main emphasis on other motorcycle features than outright machine performance.

These qualities of Supermoto put Highland Group’s spotlight on that sport when the company looked for a new focus in their product development in early 2006. Highland Group is a spearheading motorcycle design house that develops complete motorcycles for established brand owners.

For Highland, Supermoto presented the ultimate environment to test motorcycle performance where it comes to stress, shock and fatigue loads. Developing a Supermoto motorcycle, and racing it against established brands with success, would testify of Highland’s expertise and skill in product development. Their first idea was to develop a new motorcycle frame replacing carbon steel with aluminum.

Outokumpu’s R&D unit for automotive applications, Prinox, caught wind of Highland’s ambitions and jumped in, introducing high-strength stainless steels as optimal materials to create a frame with superior stiffness and strength. Prinox managed to convince Highland of the benefits of Outokumpu’s high-strength stainless steels with arguments on weight, fatigue strength, formability, and cost.

Highland engineers lacked experience with stainless steel, so they partnered with Prinox in product development. The result, a complete prototype motorcycle with a stainless steel chassis, was presented at the Milan Motorcycle Fair in November 2006, nine months after the beginning of the product development process.

The main frame of Highland 450cc Supermoto is in austenitic HyTens1200®, and the engine cradle and rear sub-frame are in duplex LDX 2101®. The chassis weight is 20 percent less than that of the best rivaling motorcycles. The precisely tuned chassis stiffness gives Highland 450cc Supermoto additional competitive advantage over its competitors.

A number of factors put a stainless steel frame at a distinct cost advantage over an aluminum frame. For example, austenitic high-strength stainless steel has excellent formability in the cold condition, whereas aluminum requires lengthy procedures and elevated temperatures to transform it to a state where it can be used for applications such as this. Stainless steel also requires no surface treatment, whereas aluminum requires anodizing. 

HyTens® stands for high-strength austenitic stainless steel grades specifically developed for the needs of automakers. Among their many benefits, HyTens® products can reach strengths many times higher than carbon steel in cold deformation, allowing considerable weight savings in structural components. HyTens® is highly formable, putting few limitations to component shapes.

The engine cradle and rear sub-frame of Highland 450cc Supermoto are made from LDX 2101® square tubing. This is the first tubular application of this duplex grade. LDX 2101® tubing features a combination of high strength and formability unmatched by competing tubular products. It is expected to find many uses in the automotive and other sectors, according to Stefan Ekblad of Prinox.

The success of Highland 450cc Supermoto, on and off the track, spells out the message of Outokumpu to the transportation industry. Mr. Ekblad says, “Our success helps to raise awareness of stainless as a material for structural engineering, particularly in applications subjected to dynamic loads.”

Racer Martin Lind comments on his ride: “The Highland bike is very stable, yet nimble and easy to flick from side to side in turns. This is because we have achieved a favorable distribution of stress throughout the frame. Also, we have managed to reach a very low frame weight and, as a result, achieved a low center of gravity.

“A major difference from my previous bikes is that this one is very predictable in its response when you’re over the limit. You don’t get into trouble as easily on this bike as you do on the competition. Other than that, I can only say that you need to ride the bike to get the feel of it and understand how fantastic it really is!”

Martin Lind on Highland 450cc Supermoto. Courtesy of Highland Group

Highland 450cc Supermoto at Elmia 2008

The stainless frame of Highland 450cc Supermoto. Courtesy of Highland Group

Elmia is the largest subcontractor trade show in Scandinavia, catering for the needs of all manufacturing industries. There were more than one thousand exhibitors at the Elmia show of November 2008, among them Outokumpu as the only stainless steel producer. Visitors numbered approximately 15,500.