THUNDER BAY — When you change your vehicle's wheels from summer to winter treads in the coming months, you're well-advised to ensure the lug nuts are properly torqued.
In fact, you may want to check them right now.
This summer, Thunder Bay OPP have investigated several wheel-detachment incidents resulting from lug nuts being incorrectly torqued and causing wheels to fall off at highway speeds.
Police on Tuesday released a photo taken after an incident in May on Highway 61 at Barrie Drive.
During a routine traffic stop, officers discovered two of five lug nuts missing from the wheel of a vehicle driven by a local resident.
The motorist was charged with driving a vehicle with a critical defect that made it unsafe, and the vehicle was ordered removed from the road pending repairs.
According to CAA, most wheel separations happen in May and June, a couple of months after vehicle owners have switched to summer tires from winter ones.
It says that's because some home mechanics and garages don't properly tighten the retaining bolts and lug nuts that hold wheels in place.
If they're not tightened enough, they can come loose, but if they're on too tight they can break loose.
It's strongly recommended that home and professional installers alike use a torque wrench rather than an impact wrench or lug wrench when changing tires.
Done-Rite Tire & Auto manager Matthew Dobson said lug nuts should always be tightened to the torque (or tightness) specified by the car manufacturer, then checked again after driving for some time.
"There's different torques for each vehicle on how tight, how many foot-pounds, are required. We have operating systems that give us specifications for each vehicle, for every nut and bolt."
Torque requirements can be found in vehicle manuals or online.
Dobson said it's also important to make sure surfaces are free of debris, specifically the hub and the back side of the wheel.
"Both those need to be clean. Clamping force is what holds the lug nuts, pushes the rim against that hub, and it's all about the clamping force. If those surfaces aren't clean, then it can shift and move around, and potentially that wheel could start to loosen off."
Even after wheels have been properly installed, he said the lug nuts should be re-torqued after about 100 kilometres of driving.
"We torque once in the shop when the tires go on, then we drive the vehicle around the block, then we do it again. Even after those two torques, we still recommend the customer comes back after 100 kilometres."
Owners installing wheels on their own should also tighten lug nuts in an alternating or "star" pattern, to ensure a uniform distribution of load across the wheel mounting surface.
