Take a peek behind the curtain at Yamaha’s forged aluminum alloy rims

You might not think of aluminum as complicated, but there are a whole range of carefully determined factors that affect every part of your motorcycle. Yamaha Motor Company takes pride in its aluminum alloys and forging processes, and credits its care to the piano frame casting roots of its parent company.

How do you improve these processes, if you are Yamaha? Materials science, baby. Just having a simple recipe to follow and a few pouring temperature instructions isn’t enough either. After all, think about how a simple cookie recipe can dramatically change between different hands. Aluminum may not be edible, but at least as many variables affect the finished product as the taste and texture of your favorite chocolate chips.

It is precisely this kind of innovation that has led Yamaha to concoct exactly the right combination of ingredients for their forged wheel manufacturing process. You will find that these wheels take pride of place on the 2021 MT-09, where they use a special flow-forming process from the research of Kahori Oshima, specialist in the Yamaha Motors Materials division.

“Just changing a few conditions can completely change the way aluminum reacts, or its ‘personality’ so to speak,” Oshima said in a statement. “It can be very sensitive at times, often leaving us with zero margin for adjustments. ”

“Yamaha has a huge collection of aluminum ‘recipes’ created by our predecessors and this is one of our strengths. We have a philosophy here that aluminum is one area of ​​manufacturing where we should never be out-rated, and I think what’s behind that is the fact that Yamaha has long been casting on its own. This confidence and pride drives us, ”added Oshima.

Of course, Yamaha are more than happy to keep their exact recipes and processes to themselves as proprietary materials. What they will tell you is that these new forged alloy wheels weigh about 0.7 kilograms (1.54 pounds) each less than the wheels they used before. That’s a significant unsprung weight saving, right there. Yamaha claims to have achieved this weight reduction by reducing the overall thickness of the wheel to just 2 millimeters, up from 3.5mm previously.

“What we struggled with the most was not having to keep track of metrics. Without them for evaluation, we cannot determine where we should set our goal, so it was certainly difficult to develop a material and build a suitable evaluation method at the same time, ”Oshima said.

“For example, if it’s all about strength, aluminum can’t beat iron. But on the other hand, aluminum has advantages such as its lightness, corrosion resistance, high machinability and beauty. Even though our Monozukuri [Japanese cultural business concept of craftsmanship] changes in the future, I am sure that aluminum will remain a material of choice. I believe my role as a materials researcher is to extract and enhance this potential, ”Oshima concluded.