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A mechanic checks a car's wheel alignmentHandout

Driving with wheels that aren’t aligned correctly can increase fuel consumption, worsen tire wear and be a safety hazard, but it is tough for drivers to notice when the change happens slowly over time.

At a parking lot near Toronto’s Pearson International Airport, I recently took laps with a pair of Hyundai Konas through a course of traffic cones. Both were the high-performance N model and identical – except that one, I was told, had its wheels correctly aligned while the other was out of whack. It was my task to figure out which was which.

The course for the Kal Tire demonstration included sharp turns and slowly tightening curves, and I hustled through in the first car for half-a-dozen laps. It was bumpy and stiff, and I was suspicious it might be the faulty model. The parking lot was unforgiving, though, with bumps and ridges and cracks, so I kept my thoughts to myself.

The second car felt smoother when we pulled away from the start, but when I turned into the first sharp right-hander, the tires squealed and the suspension squelched and I was lucky to stay between the cones. The rest of the course felt mushy and the car was reluctant to turn as I wanted. A couple of cones suffered as we rocked and rolled, and it was clear this was the Kona that was askew.

When all was done, the Kal Tire technicians put the two cars on a machine that checks alignment and confirmed the second car was faulty: The front tires pointed toward each other by one degree, and the rear tires pointed away from each other by one degree.

Mark Richardson drives alongside instructor Jeff McKague at an event to test wheel alignment in Mississauga.Handout

“If a tire is out by one degree, then for every kilometre you drive, you’re scrubbing it sideways for 17½ metres,” said Tim Orpen, Kal Tire’s manager for mechanical programs. “We’ve driven these tires for about 200 kilometres and you can see the wear on them already.”

Most drivers would be able to discern such a marked difference in a comparison test, but when you’re driving every day, there’s a danger you’ll act like the proverbial frog who is slowly boiled alive – the frog doesn’t realize the water is gradually getting warmer until it’s too late.

Last year, my two sons drove my older Toyota RAV4 for most of the summer, often on rougher gravel roads, and whenever I’d ask how it was, they’d say it was fine. When I eventually drove it for myself, it felt awful and I found that a wheel was loose, with three of its bolts only finger tight. They never noticed because they drove it all the time.

It’s the same with wheel alignment, which can easily be knocked out of whack by potholes or rubbing against a curb. Businesses that change tires should have alignment machines to check that all four tires are rolling straight and true, and usually, that check is free. If the wheels are out of alignment, it will probably cost from $120 to $150 to realign them.

Checking the wheel alignment of Mark Richardson's 2006 Honda Civic.Handout

Alignment-measuring machines are expensive, costing between $20,000 and $80,000, depending on the technology, and they can measure within thousandths of a degree. They check for correct camber (the vertical angle of the wheel, which should normally be almost 90 degrees to the road), caster (the vertical angle of the wheel compared with its shock absorber) and toe (the parallel angle of the two wheels to each other on the axle).

Different vehicles have different recommended ranges for measurement and they’re incredibly precise. Performance cars might be set up to have their wheels pointed slightly away from each other to quicken their steering, and perhaps have some positive caster and negative camber to increase their steering effort and stability on corners.

I was astonished at the dramatic effect on stability of the poor alignment on the second Kona. The wheels looked just fine, and had felt fine in straight driving.

Vehicles with larger wheels are more prone to misalignment, said Orpen, and today’s tires are often more absorbent of road bumps and faults, and so less likely to provide feedback to the driver. At best, poor alignment will increase fuel consumption and wear out a tire more quickly; at worst, it will affect the car’s sensors and safety systems.

“The newer cars are going to have lane-keep assistance,” said Dan Martin, regional manager for Hunter Engineering, which made the machine that measured the Konas’ alignment. “If you’re not properly aligned and the car’s safety systems don’t know where straight-ahead is, then that feature could actually be pulling you into traffic or the ditch. If it’s looking in the wrong direction, it’s going to be pulling you to one side.”

I had driven to the test in my 2006 Honda Civic, still with its winter tires installed, though I’d planned to swap them myself for new all-weather tires the next day. Martin and Orpen put my Civic on their machine and found the camber of the right rear wheel was more than half a degree out of alignment.

I left the test site with my tail between my legs and made a call to my local dealership to install the tires in their shop. Some things really should be left to the professionals.

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