TORONTO -- As more Canadians use winter tires, the line-ups are getting longer at auto shops in the fall and spring for change overs but safety advocates say there is one crucial step in the process that many drivers aren't following.

Brian Patterson with the Ontario Safety League says even though tires shops and mechanics recommend going back and having wheels re-torqued after they are installed, many drivers don’t bother to do it. Many car owners who switch over tires themselves may not even own a torque wrench.

"If you change your tires the same way a professional mechanic does it there is nothing wrong with doing it yourself, but if you do it on the fly and you're not following all the safety steps you could have a wheel come off just as we have seen in the past week," Patterson said. 

Nearly 70 per cent of Ontario drivers now use winter tires, which is up from 56 per cent five years ago. Ontario’s Associate Minister for Transportation in the GTA, Kinga Surma, said the government wants to encourage drivers to take the extra step and have their wheels re-torqued. 

Winter tires

"When you are installing your winter tires you'll want to come back to your mechanic after driving about 100 kilometres to make sure they are installed properly to keep your vehicle safe," Surma said. 

On Nov. 19th, a wheel came off a UPS truck and struck a convertible on Highway 407 in Markham. There have also been other cases of wheels coming off vehicles and becoming projectiles on the highway. In some cases, the wheels came loose not long after a fall or spring tire change over. 

A mechanic can check your car manufacturer's specifications and use a torque wrench to make sure your lug nuts aren't too tight or too lose. Most auto shops will re-torque your wheels for free. It's usually just takes a few minutes and an appointment may not be required.

Patterson said if you have your wheels changed by a professional mechanic they can also grind away rust from the wheel hub and tire rim to ensure good contact. They may also be able to spot problems when the wheels are off. 

"Just today in this shop when the mechanic was changing tires he noticed the customers brakes were almost completely worn out and recommended they should be replaced," Patterson said.