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Sure-grip international maintains its hold on skate industry innovation

Advanced Polymer Alloys Llc : 20 February, 2007  (New Product)
Looking at the smooth, sleek, and colorful designs of today
Looking at the smooth, sleek, and colorful designs of today’s inline skates, it’s hard to imagine how much technology, engineering and manufacturing, has impacted the sport. In 1760, John Joseph Merlin strapped on his new invention, an inline roller skate, at a masquerade party in London. He promptly crashed into a mirror. Today, while spills haven’t been eliminated, skate engineering continues to evolve, making the sport safer, more exciting, and when desired, faster.

For nearly 80 years, Sure-Grip International (formerly Sure-Grip Skate Company) has contributed to the evolution of the sport. The company is considered among the world’s top manufacturers of roller skates, accessories, and more recently, skateboards. Founded in the 1930s by John L. Wintz, the company has always exhibited a propensity for being on the cutting edge.

In its early days, Sure-Grip manufactured just roller skate wheels using gear fibre and rubber inlays. The fibre, made with a phenolic resin, an early form of plastic, provided the wheels with long wear, while the rubber inlays gave them a stronger grip to help negotiate turns. The new design helped revolutionize the skating industry by replacing slippery wooden wheels. It allowed skaters to increase speed, hold turns, and improve dance or show steps.

The company evolved and in 1945 introduced its first four-wheel roller skate (quad skates) and enhanced it two years later with the “Double Action” feature that used large, rubber cushions and a rubber pivot insert in the skate trucks. The improvements provided skaters with better maneuverability and better turning capability. The “Double Action” feature was considered a huge step forward and is still used in the modern design and manufacturing of Sure-Grip skates.

The company manufacturers 18 conventional skate models and 11 inline models, as well as a line of wheels and other accessories. The products retail anywhere from $60 to $100 per pair with custom skates available at more than $1,000. Brand names owned by Sure-Grip include Snyder Skate Company, Rock Skates, and Nova. And, the company continues to push the envelope in product design.

While Sure-Grip is the last of the large skate manufacturers to produce its products entirely in the U.S., it continues to feel pressure from overseas markets. The desire to keep the company’s manufacturing facilities in the U.S. is partly the driving force behind its continued innovation.

“We are reluctant to take our business to Asia, but it becomes more difficult every year,” said Jim Ball, owner and president of Sure-Grip. Ball, who runs the company along with Ralph Jenney, has worked with the company since he was a kid and can remember making thousands of wooden wheels to help his grandfather meet the demand. “We constantly look for ways to improve our products while reducing costs in order to keep our operations here in the U.S.,” he said.

Several years ago the company switched from using natural rubber to thermoplastic urethane in the cushion component of its “Double Action” skate trucks. The cushions are placed on the bolt that attaches the truck to the shoe. They are positioned between the pivot and a cushion retainer on each side of the axle. While rubber was likely the best material at the time, it was costly and complicated to process. But urethanes proved only a Band-Aid™ solution to the problem.

Two years ago, the company decided to change materials again, this time adopting Alcryn® Melt-Processible Rubber™ from Advanced Polymer Alloys (Wilmington, Del.) after a long search for an alternative. Alcryn MPR offered Sure-Grip advantages that urethanes, natural rubber, and other products did not, including better processing characteristics and physical properties that were closer to the ideal, but more expensive, thermoset rubber.

“Urethane was fine and it lasts forever,” said Clay Stadler, president of C-Tech Tool & Molding (Englewood, Colo.). “But when we’re looking to reduce costs we have to consider other less expensive and more molding-friendly options. Urethanes are hard to run. TPU cycle times are too long and it just takes longer for urethane parts to set. Alcryn processes much quicker and its cycle times are better for us. On top of that, the end product looked better and even performed closer to the rubber standard.”

C-Tech Tool & Molding has produced Sure-Grip skate components for 20 years. It was Stadler who made the initial recommendation to change from urethanes to melt-processible rubber. The molder produces more than a million cushions made of Alcryn MPR each year, enough to equip 125,000 pairs of skates. At the height of the sport’s popularity, C-Tech was the largest in-line wheel molder in the world, producing 750,000 wheels per week running 18 machines, 24 hours a day. As the sport has evolved, the low-end parts molding was moved overseas, leaving C-Tech to focus on the high-end, high-performance components, including wheels and truck assemblies.

Ball said that the most important element of the cushion is that it offers excellent rebound. But abrasion, tear strength, and resistance to weather conditions like sunlight and ozone, were also important.

“Our skates are used both indoor and out, so we need to make sure the components can handle the different conditions the skates will be exposed to,” Ball said. “The cushions need to rebound to close to the original size after each turn or manipulation of the skate. Skaters need to be able to trust that our skates will hold up.”

While Stadler’s molding experience helped identify Alcryn MPR, other materials were also considered before eventually being rejected. “I gave Jim and Ralph three or four different options, including TPVs, different durometers of urethane, as well as other elastomers,” Stadler said. “They were all great materials but for this application Alcryn is better. It processes better, has better performance – it is the best product for that application.”

Running Alcryn MPR, Stadler said, has improved the skate quality and has helped maintain production costs.

“Our rejection rate is almost zero,” he said. “Within the first two months we knew the change was going to work based on the test results. After a few more months, we had 100-percent feedback and there was nothing negative about it. It’s easier to process, functions better, and produces zero scrap.”

There were some initial production challenges that needed to be overcome, including eliminating side shrinkage, as well as producing flat and parallel parts. But, after the newly molded cushions successfully passed Stadler’s processing tests, it was up to Sure-Grip to road test the finished product.

“We have a few local roller rinks that we have relationships with,” Ball explained. “We put the cushions on rental skates at these rinks because they get used much more often. We found that if you ask someone to test something, they look for problems. Using the rental skates allows us to get a more accurate picture of how the material performs.”

Similar tests proved the undoing for the Santoprene cushion concept. “We had miserable luck with that material,” Ball said. “It broke down much too fast. The wear and tear is what we noticed first.”
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