Triumph Motorcycle Case Study
Extending Belt Drive Life on Triumph Motorcycles
Triumph motorcycles are known the world over for classy design and creative engineering. Those qualities extend to its Thunderbird and its impressive belt drive system.
Based in Hinckley, England, Triumph Motorcycles has a long history of engineering innovation. In 2004, Triumph began developing a mid-size cruiser. The market places certain demands on cruisers. They need a clean-running final drive and long intervals between maintenance to keep them on the road. Both of these demands called for a belt drive system. But Triumph hadn’t manufactured a belt-driven motorcycle since the 1920s.
Triumph Teams Up with Gates—the Proven Partner
According to Simon Warburton, Triumph’s Product Manager, “Belt drives were new to us, so we needed a partner who knew what they were doing. We recognized Gates preeminence in this field.”
Gates engineers took on the challenge. They knew the limitations of conventional belt drives, whose die-cast or billet aluminum sprockets typically lasted only 2,000-5,000 miles. Gates was no newcomer to motorcycle belt drives. Earlier drive designs with Gates Poly Chain® GT® belts running on hard chrome finished sprockets were lasting 30,000-50,000 miles. Belts and sprockets wore at about the same rate, so manufacturers advised users to replace both at the same interval.
Triumph Turns to Gates for a Custom Solution
But then along came Gates Poly Chain® GT® Carbon® belt. With stronger-than-steel carbon tensile cords, this belt was outlasting the sprockets. Worn sprockets shredded the belt prematurely. So Gates and Triumph took a new look at the sprockets to develop a more durable, corrosion-resistant coating. The goal: make the sprockets last as long as the belts. Gates engineers took a hard look at the industry’s hard chrome metal finishes. They explored adding more coating material. They experimented with new formulations. But one hurdle kept presenting itself: hexavalent chromium.
The traditional hard chrome plating process produces hexavalent chromium waste, a human carcinogen (remember Erin Brockovich?). The EPA was lowering threshold limits on hexavalent chromium, resulting in safer but costlier plating and waste disposal techniques. So Gates and Triumph went looking for a “greener” coating—one that would provide even greater durability and corrosion resistance than hard chrome plate.
Gates engineers tested dozens of coatings. The best contenders were sent to Triumph for salt spray resistance testing and live tests on motorcycles. The winner was called Gates Armour-GK™. This proprietary coating produces a surface that outperforms hard chrome plate by a factor of 5 to 1 in terms of wear resistance. The coating’s chemistry and method of application to the base metal form a nearly impregnable “skin.” And it’s environmentally friendly in the bargain.
Now Thunderbird Motorcycles Go Twice the Miles of Competitors’ Cruisers
Now the Thunderbirds are rolling off the assembly line. The bike was unveiled in Barcelona, Spain in May 2009. Sixty-five journalists rode, prodded, and penned with enthusiasm. And the question was frequently asked: “Is it a Gates carbon belt drive?” The answer: “Yes, and Gates Armour-GK sprockets as well.” Time will tell, but tests indicate that this belt drive could go twice the miles of competitor cruisers before belt or sprockets need to be changed.