This may be obvious, but if you have four wheels on your car, it helps if they all point in the same direction. It only takes a small misalignment, invisible to the naked eye, to begin having consequences.
What causes misalignment?
Impacts with curbs, potholes and speed bumps will cause misalignment. Over time, your suspension springs, bushings and joints succumb to wear, and things drift out of position. The longer it’s left, the more ingrained that wear becomes and the harder it is to permanently correct, which is why inexpert alignments often fail to cure the problem.
Most vehicles will develop misalignment, so an annual check is sensible.
Why it matters
Your steering becomes more sluggish, the vehicle and steering wheel can pull to one side, and the tyres begin to wear unevenly. Stopping distance increases and your tyres become less safe. Fuel consumption may rise. In bad cases, the steering column vibrates and you have to hold the wheel off-centre to steer straight.
MOT and insurance
Wheel alignment itself is not checked in an MOT and therefore has no direct bearing on your insurability. However, many of the consequences of misalignment are checked; improperly worn tyres and steering issues will fail you.
The insurance situation may be different for fleet vehicles as motor trade insurance providers can set their own conditions to ensure vehicles are properly maintained. See quotemetoday.co.uk/motor-trade-insurance.
If your road traction and steering are affected by misalignment, you’re more likely to have an accident. That’s not good for your insurance, either.
Not all garages have the equipment for wheel alignments or may have equipment that is only suitable for two wheels at a time. The front wheels are more prone to issues, but it’s better to test all four together, so check that the garage has a four-wheel laser aligner; you can see what one looks like at https://www.garageequipmentonline.com/products/wheel-aligners/.
A wheel alignment entails checking both the direction the wheels point and their angle to the ground. “Toe in” denotes wheels pointing inwards at the front, while “toe out” is the opposite. “Positive camber” is when the bottom of a wheel is further out than the top, and “negative camber” is the reverse. The “caster angle” is that between the steering pivot axis and the vertical.
Don’t pay for a four-wheel test if you have non-adjustable rear wheels.