Wide Base, Canada-Wide

Wide-base tires

Greater effort will be made to harmonise standards for wide base tires

Since at least 2001 departments of highways (DoTs) in Canada have worried that new-generation (not the old 65 series) wide base tires, sometimes called super-singles, might cause more road damage than duals. As a result, DoTs set lower maximum axle weights than for duals, hurting the competitiveness of fleets using them. Special permits to use them, and various weight limits from province to province, added insult to injury.

Thanks to a pledge announced in December 2018 by Canada’s First Ministers (provincial premiers) to work harder to harmonise wide base tire standards interprovincially, this headache may pass.

Wide base tires have several advantages. For example, Michelin reported a few years ago that converting an axle from duals to super-singles would save 200-250 pounds per axle, or about 1,000 pounds for a tandem trailer. Mounted on all the drive axles and trailer wheel positions, they can yield a fuel saving of nearly 10 percent. Drivers report that they give a more comfortable ride than duals.

In recent years some provinces, including Quebec and New Brunswick, have increased the weight limits for wide base tires. As recently as December 2018 Saskatchewan increased its weight limit for wide base tires 455 millimetres (18 inches) or wider from 3,850 kilograms (8,488 pounds) to 4,250 kg (9,370 lbs) per tire, excluding the steering axle.

Widebase WheelThe province also announced it will soon drop the requirement that fleets wanting to use them buy permits.

Saskatchewan announced in November 2018 that it would harmonise its wide base tire limits with Ontario. And back in June British Columbia upped its weight limit per axle for them to 8,500 kg (18,739 lbs). In 2017 Alberta raised its wide base tire weight limit to be at par with duals.

Underlining the challenge provincial DoTs face though was a note in that Alberta announcement that while the provincial government can change its standards, it cannot mandate that change in municipalities, some of which forbid wide base tires.

While the First Ministers announcement is great news, equalizing the standards country-wide won’t happen overnight.

“This is a multi-step process which generally takes some time,” says Geoffrey Wood, Senior Vice President, Policy, Canadian Trucking Alliance. “Although the First Ministers have communicated their intent, formal amendments to the National Memorandum of Understanding on Weights and Dimensions must be finalized by the Council of Ministers and Deputy Ministers responsible for Transportation and Highway Safety and signed off by each province.”

No timeline for achieving all this was mentioned in the First Ministers’ pledge.

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