Wheel alignment servicing is a growing market in the retail tyre sector. There are tyre shops and garages nationwide that are carrying out ‘alignment checks’ but at various levels of competency.
At its lowest level, the customer is offered a poor service. The resultant effects may not be immediately apparent to the business owner, but long term effects could be the business will suffer poor customer retention and lose recommendations that are all so important.
At the top end of the scale is where a highly professional service is provided, one that is both accurate and informative for the customer and will involve following procedures (as those recommended by the car manufacturer) to get the car measured. With the sophistication of cars geometry and suspension of today, it is recommended to measure a minimum of the 14 primary alignment angles. The simple printout shows the customer if their car is ‘in’ or ‘out’ of tolerance.
The tolerances issued for the latest generation of cars, can be quite tight and errors in measurement may lead to either; wrong diagnosis and wrong advice or even adjusting a correctly set car back to out of specification! So it is important to ensure you are carrying out the correct procedures and measuring accurately.
Pre-check.
Ahead of putting on the alignment ramp, all cars should be inspected to check all steering and suspension components are in a serviceable condition and tyre pressures are correct. Worn components giving play in the steering and suspension will give inaccurate and non repeatable readings. This is often done on an adjacent two post lift.
Run-out compensation prior to obtaining alignment readings
Advancements in technology and increasing demand for accuracy is necessitating a change in alignment practices. Tracking gauges or similar hang-on style systems, using the ‘resting the pins against the wheel rims’ method, does not take into account any errors in the outer edges of the rim (wheel rim run out). These systems have been convenient and fast, but in summary if a direct reading is taken, where wheel rim run out is present, will result in alignment measurement errors.
The ‘big four’ German car manufacturers (amongst others) all have investigated the effect of run-out compensation and are insistent that reading should either not be taken from the wheel rim edge or that if they are (taken from the wheel rim edge) then run out compensation must be performed.
Also Bosch commissioned a study on run out compensation, again to help clarify the matter. The results of the study highlighted the typical, and quite significant errors, errors that occurred for both steel and alloy wheels and concluded ‘rim run out compensation is absolutely necessary’. Clearly with very tight tolerances for the ‘in-specification’ errors introduced by failing to eliminate rim run-out, results in a less accurate reading.
In the early days skipping wheel rim run-out may have saved time, when alignment was in its infancy, as back then professional four wheel alignment did take considerably longer. Now with latest aligners, it takes virtually the same time to measure all four wheels properly – using a short roll back for elimination of rim errors.
Specification for load or ride height conditions
Each car manufacturer issues the alignment data for cars under certain conditions. Clearly an ‘unloaded condition’ is the simplest. Some, like BMW, may give either a load requirement or more recent models a set ride height that should be present. (which may require loading to achieve). Measuring cars and selling adjustment work, when the car is not in the correct position, will not only mislead, but again could give the wrong readings. So checking for these ‘special conditions’ for each car type is very important.
Adjustments
When a wheel is adjusted for toe or camber, it is essential the wheel is free to ‘float’ on a friction compensated turn plate. If not , then torsion builds up in the tyre sidewall and after the alignment angle of the wheel is adjusted/brought into tolerance and the car moved – the wheels will then ‘over adjust’ and the readings will change. Quality turn plates are a ‘must’ for professional four wheel alignment servicing. Don’t forget that the ‘turn plate’ is in a non friendly environment and regular checks, cleaning, air blowing off is necessary.
In summary
Today’s clever thinking ‘wheel alignment servicing entrepreneurs’ are those who measure all four wheels in a manner that incorporates both good practice and the recommendations /procedures of the car manufacturer; which ultimately leads to greater accuracy and the credibility that comes with it. In so doing the workshop will build a reputable and very profitable alignment service, with increased business and good customer retention.