Trust. In this life, you’ve got to have three people you can trust: a good doctor, a conscientious lawyer, and an honest mechanic.

Of course, life’s a little more complicated than that, and these days you might need both a reliable nephrologist and a straight-shooting expert on patent law. Still, while little specialization may be called for, the principle remains the same – when you need something done by someone who has more expertise than you, the most valuable person is the one you can trust to do it properly.

These are the guys I trust with my car. I’ve been taking the ol’ Subaru wagon to Jason Trentini and his crew at Dale’s Alignment and Brake in Langley, BC for years. Any time there’s something suspension-related to handle, it’s always the same routine. The car rolls in, Jason runs me through what needs doing, the work gets done, and I usually end up paying less than I expected. It’s an hour drive to get here, and worth every drop of fuel.

The best part about the shop is that it’s no Wizard of Oz operation. Just after dropping in at the HPA tuning shop – the crew at Dale’s handles the alignments on their cars too – I popped over to see what Jason was working on, and have him walk me through just what an alignment shop does.

In a Hot Wheels, the wheels are bolted straight on through a pin-thin axle. In a full-size car, things get a bit more complicated. Way more complicated.

Leaving aside the various types of suspension (multi-link, coil-and-spring, leaf-spring), there are three primary angles to look at when considering the alignment of a car: caster, camber, and toe. There’s a navy blue 2005 Toyota RAV4 waiting to roll onto the lift, so let’s start with that.

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The machine Jason’s going to use to check the specs on this 150,000km daily driver uses four clamp-on reflectors and a camera system to check the various angles. This particular one’s made by a Canadian company, John Bean, and it contains a database of manufacturer factory settings to compare the measurements to. Jason hooks it up, initializes the system, and runs through a series of prompts.

The first angle to consider is camber, or the angle of the tire to the vertical when viewed head-on. If the value is negative, then the bottom of the tire is angled out away from the car, giving it an aggressive look. If the camber is positive, the tire angles in at the bottom, looking a bit bow-legged.

If all your car ever did was travel in a straight line (hello, prairie-dwellers!) you’d want your camber value to be as close to zero as possible, maximizing the contact patch. Because we take corners (and the more the better, right?), some negative camber is good. Think of a motorcyclist leaning into a corner – the weight transfer in the car ends up pushing the tire against the pavement and you carve up your turn. Obviously, only racetrack applications want to maximize this setting, as in a road-car the angled tire will wear out the inside edge far too quickly.

The next primary angle is caster. This is slightly harder to visualize, but concerns the angle of the suspension, and what happens when the wheel is turned. Most caster settings are positive, meaning that the suspension is slightly raked back towards the car, which improves high-speed tracking. If you’d like to know why, just picture what happens to the wonky wheel on a shopping cart – attached near the front, it waggles around at random, and next thing you’ve plowed into a pyramid-display of baked beans.

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The final primary angle is called toe. This is very simple: toe-out is exactly what you think it is, with the car’s wheels splayed outwards, and toe-in is the reverse, with the vehicle’s tires pigeoned-in. The more the toe out, the dartier the steering, the more the toe-in, the more stable the car. Think of it like skiiing, when you start out, everybody does the snowplow. Like all the other measurements, there’s a Goldilocks “just-right” point to be reached.

The little RAV4 has scored well overall, only slightly out up front for both camber and toe. However, Jason’s experienced eye doesn’t like the way the tire wear looks out back, and sure enough, the rear springs have sagged a little, increasing camber out of spec.

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“Some manufacturers will bump their tolerances,” he says, reaching for a socket wrench, “For instance, Mazda bumps the allowable camber and toe on their Mazda3 because they all sag after a while.” There are two eccentric bolts underneath the RAV4’s subframe that may allow for the camber to be dialled back into the green, and Jason flexes his muscle against seven years of road corrosion.

Problems with caster would be much more serious. Usually caster isn’t adjustable without special aftermarket subframe adjustments, and a variation out of factory specs is an indication of a collision that’s been improperly repaired. How common is this?

“Very common,” Jason says, “Especially when ICBC [the provincial insurance company] auctions off vehicles that are deemed “fixable”. Even though the repair facility has to have the vehicle inspected and an alignment performed after the repair, many slip through the cracks.”

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An alignment is a diagnosis tool when something like tire-wear becomes an issue, and/or a good way to check the health of a used vehicle you might be considering purchasing, especially if it doesn’t have a perfect history. Of course, it’s also something to be done any time suspension modifications are performed.

The RAV4’s bolts prove rustily stubborn, and as Jason knows the price of a broken bolt, as well as the cost/benefit analysis of replacing rear springs simply because of a slight sag, he puts the front suspension in-spec, makes a few notes, and heads off to advise the Toyota’s owner. A little rear tire wear here might be liveable, and with front toe corrected to spec, proper rotation will spread out the life of the rubber a little longer.

Next on the lift is a tuned-up Dodge SRT4 (pictured at the top of this page), recently picked up by a younger owner. These are great bang-for-buck cars: basically, Dodge’s SRT division decided to channel Carroll Shelby and turbocharged the heck out of a four-door Neon. Hilariously overpowered even in stock form, they’re capable of putting the hurt on some high-dollar performance machinery.

Unfortunately, the entry-level pricing sometimes means that modifications are done on the cheap. This car had no-name-brand coil-overs on it when purchased, and they provided a ride that make the car skip like a stone over imperfections in the road. The new components that Dale’s installed are of much higher quality, and have had a chance to settle – the car’s back in for an alignment follow-up.

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Lowering cars is a tricky business. Obviously dropping a car’s centre of gravity is good, but too low and it’s not just excessive camber and curb scrapes you need to watch out for. “There are other angles called roll centre, camber curve. We reduce the ride height of a vehicle to gain performance handling but if you go too low these angles are affected which will cause poor handling with more body roll, and bump steer.”

As the aftermarket performance parts on the SRT4 are fully adjustable, Jason is able to dial in more aggressive camber and toe settings than in the grocery-getter Toyota. He doesn’t go too far – this is a street car more than a dedicated autocrosser, but the improved ride will also come with more direct steering and a quicker response.

On the opposite side of the equation is the Toyota Tundra that’s up on another hoist in the garage. This truck’s been lifted, the off-roader’s suspension modification of choice, but it’s been done properly here. When it’s not done properly? That’s a problem.

“Camber can end up being too positive, it also lowers caster on most trucks – this will cause wandering, a very common complaint,” Jason explains, “Low caster will cause a gyroscopic effect on the front wheels/tires referred to as “death wobble” which is very common on [improperly lifted] fullsize Dodge/Ford trucks – when this happens at 80km/hr it can become dangerous.”

Um, it’s called the “death wobble”. I think “becomes dangerous” might be an understatement. Happily, the more-reputable aftermarket suppliers all have camber and caster correction kits to give your truck the beefy off-road look without the unintentional off-road excursions.

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Other terms that pop up on the alignment machine’s screen include SAI for Steering Axis Inclination and Thrust Angle. The latter is a measure of how well the vehicle’s four wheels line up – if it’s off, the car will dog-walk down the road slightly sideways. Likely you’ve seen an improperly set up Jeep Wrangler or similar solid rear-axle machine putting on this crabwise performance.

SAI, Included Angle and Scrub Radius are all important terms for the engineers who built your car, but they are not ordinarily adjustable. If they’re out of whack, there’s something bent in there somewhere, and it’s up to your mechanic to track down and replace the bent part.

Part of the reason I keep coming back here is that I’ve never seen anyone at Dale’s up-sell an alignment if someone’s come in to get brakework done, or just an oil and filter change. If there’s a problem, the customer can usually spot it through tire wear or an off-centre steering wheel.

If you’re noticing either of these problems, your vehicle is pulling to one side or another, you’re planning on changing your vehicle’s ride-height, or if you’ve just hit an extra-big pothole and are concerned that something’s gone amiss, it’s the right time to have your car’s alignment checked. More than that, it’s best to have it done by someone you can trust.