According to the Rubber Association of Canada, underinflated tires rolling on Canadian roadways waste enough fuel to power 275,000 vehicles for a full year. That’s an estimated 533 million litres of fuel this year! Underinflated tires will add an extra 1.2 million tonnes of CO2 into the atmosphere, increase tire wear and affects vehicle handling. A study commissioned by the Rubber Association of Canada showed that one-third of Canadian vehicles have at least one underinflated tire.

Newer vehicles have tire pressure-monitoring systems to warn drivers if a tire is low on pressure, but these systems are not programmed to warn if a tire may be slightly low and wasting fuel. Visually checking tires isn’t good enough either. A tire that is dangerously low on pressure may look the same as one inflated properly. The only sure way to check tire inflation is to use a tire pressure gauge and use it often.

Tire pressure gauges are not expensive. For well under $10, there are simple gauges with a sliding scale that is pushed out by the tire pressure. These gauges are fairly accurate but can wear, become gummy with dirt or become damaged. If the gauge shows erratic readings, then the gauge should be replaced.

Digital electronic gauges are becoming more popular, although I find they sometimes don’t work well when stored in the glove box during a Canadian winter. They need to warm up first. The gauges used by those who need accurate tire pressure such as race teams, are glycerin-filled round mechanical gauges with a flexible hose to reach the tire valve stem. These gauges may sell for $30 or more but they make a great birthday or Christmas gift and will quickly pay for themselves in improved fuel economy. A driver who travels 20,000 km a year will save more than $100 in fuel if the tires are inflated properly.

RIGHT AND WRONG WAYS

With gauge in hand, checking tire pressures is a simple task but there are right and wrong ways to do it. The first thing you need to do is locate the tire pressure specifications for your vehicle. These are found on a decal often on the driver’s door or door jamb. Sometimes the decal is in the glove box. If you can’t find the label, call your dealer for the information. Don’t inflate the tires to the pressure shown on the tire sidewall. This is the maximum pressure the tires can hold and inflating to this pressure will give a harsh ride and increase tire wear.

Tire pressure should always be checked when the tires are cold. The vehicle should have been sitting for at least three hours if you have been driving it. Tires become warm when driven and this heats the air inside the tire causing the pressures to rise. This is normal, but pressures would show out of spec.

If a tire has low pressure, it will create even more heat and cause pressures to increase. In this situation, the low-pressure tire may actually show the same pressure as other tires on the vehicle when hot, but this tire is operating too hot and could fail. If you have to drive to a service station to get air, drive slowly and no more than a couple kilometres so you can still test the tires cold.

Some tire shops fill tires with nitrogen gas rather than air. The big advantage of this is the nitrogen gas is dry. Moisture in regular air can cause tire pressures to fluctuate more as the tires heat up. Nitrogen also seeps from the tire at about one-third as fast as air. In a month, a tire may lose one psi, while it would take three months for this to happen with nitrogen. Nitrogen is pricey however and checking tires at least once a month will ensure they are properly inflated even with air.

Whether you are concerned about tire wear, vehicle safety or improved fuel economy, checking tire pressures regularly can pay big dividends.

Jim Kerr is an automotive journalist based in Saskatoon.

The post Save Fuel — Use A Tire Gauge, And Use It Often appeared first on Manitoba Co-operator.

When you take your vehicle in for an alignment, steering linkages and suspension components are inspected for wear or damage. Worn parts won’t keep the tires in alignment, so they need to be repaired before any adjustments are performed. Older vehicles may need several parts and it can be expensive. Unfortunately, a few shops that sold unneeded parts have damaged the image of many reputable shops.

If you have any doubts about whether your vehicle needs parts, ask the technician to show you the wear. Reputable shops will explain what they are doing, how they test and show you the wear on the parts. Of course, word of mouth is always a good way to find a quality shop.

With the vehicle inspected, the technician will connect the alignment equipment and take the readings. Four-wheel alignments are the most common type performed. Two-wheel alignments (front only) were the norm in the past but front-wheel-drive vehicles and those with independent rear suspensions should have all four wheels aligned. This is not as critical on rear-wheel-drive vehicles with a solid rear axle, such as pickups, but a four-wheel alignment can highlight problems such as bent rear axle housings or an axle housing shifted out of position.

CAMBER, CASTER AND TOE

The technician takes several readings. Camber is the tilt of the tire in or out at the top. Theoretically the tire should be exactly vertical to keep the tread on the ground, but suspension movement, cornering forces and body roll all affect the position of the tire, so often the tire is adjusted slightly away from vertical, typically within one-half degree of vertical in or out. Front suspensions are often adjustable, but many rear suspensions have no adjustment. Sometimes aftermarket shims can be used to adjust the angle, but if a rear camber angle is too far out of limits, it indicates a damaged or bent part.

Caster is the difference in angle of a line through the suspension turning pivot points and the vertical centre of the tire. Think of a caster wheel on a shopping cart. The wheel is offset around the pivot point to provide directional stability. Rear wheels don’t steer, so caster is not measured. Front-wheel caster provides ease of steering and directional stability. The caster angles should be close to equal from side to side with slightly less (one-quarter to one-half degree) on the left side. Slightly less caster causes the vehicle to pull to that side to compensate for the crown on the road, so the vehicle will drive straight.

Correct toe is the most important angle for decreasing tire wear and keeping the vehicle stable. The tires should be pointed straight ahead when driving. To accomplish this, the steering is adjusted either slightly in or out, depending on wheel offsets and suspension design. Too much toe will wear tires and excessive toe-out causes vehicle stability problems. It will tend to dart from side to side with the slightest turn of the steering wheel. Rear toe-out can cause the back of the vehicle to turn towards the tire with the best traction. This is most noticeable on icy roads during braking, where it can cause the vehicle to spin. If your vehicle handles poorly on slippery roads, get a wheel alignment right away.

Other angles checked include kingpin inclination, tire setback and vehicle thrust line. These angles can highlight bent suspension parts or hidden frame damage and that is why an alignment check is often a requirement when importing a vehicle from another province. I have seen a vehicle that looked perfect but the alignment showed the left wheelbase was shorter than the right by 50 mm. The body had been repaired but not correctly.

Wheel alignments may seem an unnecessary expense if the vehicle is driving fine, but correct alignment improves tire life, increases fuel economy and improves handling. It can actually save you money in the long run.

Jim Kerr is an automotive journalist based in Saskatoon.

The post Wheel Alignments Should Be Done More Often appeared first on Manitoba Co-operator.

All-wheel drive or full-time systems drive all the wheels but allow for a difference in speed between the back and front axles. This is an important attribute. If the tires couldn’t turn at different rates, they would create driveline bind on corners, where the wheels travel different distances. The driveline would also bind if the tires are different sizes (even new tire diameters vary slightly) when driving on hard road surfaces. Binding will quickly wear out drive axle gears and transfer cases in a few thousand kilo-metres. All-wheel-drive designs eliminate binding so they can be engaged all the time, regardless of road conditions.

Some all-wheel-drive systems engage both drive axles all the time. Subaru, Audi, Porsche, Mercedes and some Jeep are examples of this. There are many other examples, and all these systems are built to offer maximum traction without the driver having to do anything.

Other “all-wheel drives” are front-wheel-drive-based vehicles that use a rear axle assist. Many compact SUVs and midsize crossovers use these systems. The rear axles only drive when the front wheels start to spin. Many use computer controls to anticipate front-wheel spin during acceleration and can engage the rear axles before slip occurs. These systems provide better fuel economy, as the rear axle is only driven when needed. Some of these types of systems will have a control to “lock” the transfer case so the rear axle can be driven all the time, but it usually only can be engaged at slower speeds.

GOOD IN MUD, NOT ON ICE

Four-wheel-drive systems can lock the front and rear axles together. This provides better traction in loose surfaces such as deep snow, sand, mud or deep gravel. However, it can give less traction on ice. Because four-wheel drive creates some driveline bind, tires on one axle have to slip to reduce this binding. The slipping tire has no traction, especially on ice, so steering control and stability are hindered.

Almost all four-wheel-drive systems can be shifted so they only operate in two-wheel drive and this is preferred when the roads are icy or you are driving on hard surfaces such as pavement. This feature of being able to shift between four-wheel drive and two-wheel drive is sometimes referred to as a “part-time” system because it is operated in 4WD only part of the time.

Some four-wheel-drive systems have a low range for slow speed off-road traction. The same rules apply here as they do to operating in high range. Use it for loose surfaces but don’t use four-low range unless you need it. Get stuck in four low and you will be walking for a tow. Serious off-roaders carry a winch and anchors to help when they really get stuck!

Many pickup trucks have automatic mode in their four-wheel- drive systems. Automatic mode uses a computer to engage 4WD when there is a speed difference between the front and rear drive axles. When the drive axles are turning at the same rate, the system automatically changes to rear-wheel drive only. This system automatically switches between 2WD and 4WD and has many advantages of both, but tires do have to be even in tire tread depth. If tread depth varies by more than two-thirty-seconds inch, the system will be continually trying to engage 4WD while driving on hard surfaces and this can cause wear.

On any all-wheel-or four-wheel- drive system, tires have to have traction before the vehicle will move. Systems with a differential in the transfer case can have one wheel spinning on ice and no torque being transferred to any other tire. The vehicle is stuck! Traction control systems can apply the brake to the spinning wheel so torque is applied to the other wheels to get you out. If you are stuck with a rear wheel on ice, an old trick is to apply the parking brake slightly to slow the spinning tire. This will cause the other rear tire to turn.

Jim Kerr is an automotive journalist based in Saskatoon.

The post All-Wheel Drive Versus Four-Wheel Drive appeared first on Manitoba Co-operator.