VERNON, B.C. — After years of stability testing and hundreds of thousands of dollars in research and development, Wolf Trailer Company has convinced B.C.’s Commercial Vehicle Safety and Enforcement Branch to increase the maximum allowable weights for tridem pony trailers.

B.C. now allows full weights of 24 tonnes, provided the pony trailer is connected to the towing vehicle by a roll-coupling hitch system. That’s a three-tonne increase over previous weights, says Eric Amlin, a former researcher with the Forest Engineering Research Institute of Canada (FERIC) and now a technical consultant with Wolf Trailer Company.

The increased weight allowance will benefit truckers in the forestry, construction and oilfield sectors, he noted. And better yet, the combination, when used with a roll-coupling hitch system – is actually more stable than the same configuration connected via pintle hook, even at the lower weights.

“Roll-coupling the trailer to the truck at the higher weights is a more stable vehicle than the truck without roll-coupling at the lower weights,” Amlin told Truck West.

And there has been ample testing done to support that theory. FERIC began examining the stability of vehicle combinations using roll-coupling hitch systems several years ago and at the same time, Wolf Trailer Company was doing its own research and development on just such a device.

“Individually of each other, we both came to the conclusion that roll-coupling would be the best way to improve the stability of pony trailers,” Amlin recalled. “So, we brought our strengths together. FERIC did the testing and the vehicle dynamics modeling and (Wolf Trailer’s) Larry Wulff was doing the actual hitch design.”

There are currently four Wolf Trailer roll-coupling hitch devices in the B.C. market and Amlin said now that the higher weights have been approved, the next batch of 12 is already spoken for. Interest is also picking up in Alberta and Saskatchewan, where work is underway to prove the benefits of the systems in those provinces as well. The hitches are manufactured locally in the Okanagan and pony trailer manufacturer LangFab has worked out a deal to supply the hitches.

“With this technology in place, carriers will realize a three-tonne increase in trailer productivity and be taking a significant step forward in terms of heavy truck safety through improved trailer stability,” Amlin said.

Wolf Trailer itself has spent four years and more than $300,000 developing its roll-coupling hitch design and Amlin guesses FERIC has spent a comparable amount of time and money testing the concept. The stability improvements, Amlin estimates, are as great as 12-20% for a fully-loaded tridem pony trailer when compared to the same combinations connected by pintle hitches.

For more information, visit www.wolftrailer.com. Or you can contact Wolf at 877-258-9653 or for technical inquiries, Amlin at 250-540-9410.