We are often asked about the difference between tracking, 4-wheel alignment and car geometry. So here’s the definitions to help you understand.
Tracking is aligning the front wheels of a vehicle. We don’t provide tracking services on their own, as most garages and high street chains are capable of doing this. Most non-sports cars fall into this category.
4-wheel Alignment is more specialist – this involves the setting of the front and rear axle toe-in, and can only be done on certain car makes and models, typically higher end saloon, coupe and prestige cars e.g. Mercedes.
Car Geometry Alignment is more advanced again – in addition to 4-wheel alignment, we also adjust the camber and castor of both axles. Japanese sport, sport orientated cars and prestige cars require geometry services. Porsche, BMW, Mazda, Honda, Ferrari and Audi for example.
Chassis Tuning is the most complex service we offer. Think of it as tuning the car’s handling to meet the needs of the driver and the driving environment. Removing compromise built-in by the manufacturer that affects the handling in one environment, optimising for another like using a hypercar, not on the circuit but as an everyday driver.
Poorly aligned wheels can affect handling, speed up tyre wear, cause uneven tyre wear, increase fuel consumption, and affect vital parts responsible for steering and suspension. Not addressing wheel alignment can end up being a costly exercise.
Poor alignment of the front wheels in relation to the rear will offset the steering wheel and interfere with the straight cruising stability of the car and potentially unbalance the left and right turn. From ‘alignment blue book’, the toes are the most important settings for a wheel, bar none. They should never be compromised. Getting toe wrong can create dangerous and dramatic effects from flick-over steer (losing grip rear axle) to woeful understeer.
Before we undertake our full wheel alignment checks and perform any adjustments, we’ll have a detailed conversation with you about your car, how you drive it, and your requirements. Customer involvement is key to ensure we can meet the requirements before we start any work. We will drive the car across our evaluation route of 4 road types, testing the car against benchmark behaviour for the perfect handling car. Each customer’s goals are very different – from the way they want the car to handle and how they drive it, to and how often they use it on different road types.
After checking the car’s current 4-wheel alignment or geometry using our state-of-the-art Hunter Hawkeye equipment, we reconcile toe settings with the driving evaluation results. We then make the required adjustments, ensuring symmetry and exact settings to fine tolerances before factoring in the customer’s handling requirements. We pride ourselves on our methodical and through processes, which enable us to produce reliable and repeatable driving results every time.
Most non-sports cars have fixed cambers and castors. Cars with camber adjustment along with front and rear toe adjustment usually fall into the sports car or higher end category. Most Porsche occupy this category, except for a few like the G-series (3.0, SC and 3.2), 964, 993 and GT3 and GT4.
Camber is pre-set to achieve grip in turn. Usually, more camber gives longer lasting grip in turn. Too much or little can affect this grip. Tuning the camber to the customers’ driving style and road types can produce just the right amount of grip at each axle to produce an understeer, neutral of oversteer tendencies. The camber setting also affects traction in accelerating and braking and also the lateral stability.
The process is exactly the same as 4-wheel alignment, however in addition the cambers and castors are analysed and adjusted.
Our chassis tuning service is available for cars that have ride height adjustable suspension. It encompasses 4-wheel alignment, car geometry alignment, and other services to adjust all the available parameters within the car’s chassis, including ride heights, damper stiffness / softness, and anti-rollbar stiffness / softness.
The ride height determines how far off the ground the car sits. While lower sitting cars can handle better due to a lower centre of gravity, it’s important to know how, when and where the car is likely to be driven as lower cars can also bottom out on bumps and create issues such as bump steer and excessive camber and harsh ride comfort. An effective compromise needs to be met to balance handling with performance.
When corner weight balancing your car, we assess and adjust the spring pre-load or damper length in order to achieve the same diagonal weights. In the extreme highly tuned track and race cars have weight jacking to give advantage for circuit. In the UK that’s right turns, and the US left. 50:50 diagonal weighting ensures even handling in left and right turns, providing balance in grip front to rear. We pride ourselves in being able to achieve corners weight results to within 2kg.
Changing the bump and rebound settings on dampers when available can enable better pitch and roll control, enhancing grip as well as changing the dynamics and ride quality. By fine tuning these parameters we can complement the suspension settings for driving style and environment.
Some manufacturers provide adjustability in the anti-roll bars or upgraded by the client to cars with fixed bars. Front and rear bars are adjusted to achieve the customer’s roll characteristic (the amount of roll) the balance in turn, over-under steer and ride comfort.
Race cars need very specific adaptations to optimise their performance, normally around the chosen control tyre. Center Gravity has the market-leading equipment and specialist skills necessary to provide your car with a competitive advantage. Whether you need your ride and roll rates modifying, damper valving (car shock tuning) or race car steering geometry reviewed and adjusted, we have the experience of modifying your car to shave seconds off your performance time.
We work with race teams and racing enthusiasts throughout the UK to refine their racing cars’ suspension settings including chassis suspension and steering components, linkages, pivots, bearings, and bushes. We also assess and adjust damper, roll bar, ride height, geometry, and corner weight settings.
Dampers or ‘shock absorbers’ give control of wheels and car body over bumps and undulations and manoeuvres. Control over the energy put into the suspension springs. Simple, without damping the wheels and car would oscillate affecting control of the wheel and its grip and the car body’s stability and heave. Dampers strength is set by auto engineers carefully to match spring stiffness and ride quality.
Dampers health and efficiency directly affect the rate of turning, braking distance, control over bumpy surfaces and have a direct effect on ride quality.
In early days of our vehicle health checking damping was evaluated by driving the car on specific roads at speed to assess wheel and body control. In some cases the drive would be scary as a damper had failed leading to out of control resonance of body wheels or both.
Dampers are mostly supplied as fixed damping, however most aftermarket performance dampers as coil overs have single, dual, triple or 4 way adjustments.
The key is different car types have different strength dampers to suit the role of the car. Prestige passenger cars will have damper strength defined as the ratio 0.2 to 0.3 of critical damping (very stiff). Sports cars are typically 0.3 to 0.4. Aero LMP cars between 0.7 to 1! So if we test Mercedes ML we expect 0.2to 0.25. If we get 0.15 we have trouble. 0.12 is a fail from mot man! If he could measure it.
Usually the damper strength (damper curve force velocity) is set in the laboratory and measured on a test machine called a damper dynomometer. This requires the dampers if fitted to be removed.
Center gravity invested in a floor mounted drive over machine (Maha Beissbarth Lehr principle) that does a similar job to the bench dyno, however with the wheels on the car and dampers fitted. This has reduced the scary driving test and consequences.
There’s no point in selling car perfect control setup without testing the the dampers that have the monopoly on control.
We have 8 years of baseline data for all prestige and sport car makes, emphasis on Porsche all model years. This data gives us the experience to see the damper health and efficiency. We can even identify a damper type from its test report damper curve!
So we offer the service to test damper health, pairing on axle, correct damping for the chassis and it’s intended role as passenger, sport or track. There’s a report that we can then use to drive repair if possible or replace.
This service is included in the healthcheck package in our other services, or can be exclusively booked.
We recommend that if your dampers are more than 20,000miles old, to get them checked as their efficiency drops with wear. We don’t want control waining when you are out on your next eventful drive.
Center Gravity Limited repairs and services Porsche® cars for customers. center gravity is not sponsored, associated, approved, endorsed nor, in any way, affiliated with Porsche Cars Great Britain, or Dr. Ing. h.c.F. Porsche, AG (www.porsche.com). The Porsche® name and crest are trademarks of Dr. Ing. h.c.F. Porsche AG, and any other products mentioned are the trademarks of their respective holders. Any mention of trademarked names or other marks is for purpose of reference only.