Technical / A to Z
Technical Articles
However, for a more detailed look please see our published technical articles, which provide a more indepth look at. The articles are published below and can either be viewed online, or downloaded for future reference. As ever if you have any questions or queries, please contact us.
A to Z
As vehicle dynamics is such a complex subject it is not possible to give a great understanding without in depth reading and many years experience in this field. In order to aid understanding, we have provided brief descriptions of some of the most commonly used terms within the motorsport industry. These can be found down the right hand side of this page, simply select the word, and we'll provide the description.
- Camber
- A Camber will help to optimise tyre grip. With modern tyre constructions (eg radials) it is normal to have around one degree of negative camber (top of wheel leaning in towards the chassis).
- Caster
- A Caster works in conjunction with toe-in and king-pin angles. It gives the steering a self-centring action when coming out of corners and also aids overall car stability.
- Centre Of Gravity
- This needs to be kept as low as possible! It is the theoretical point that the car will balance from if it were suspended in free air. From a handling point-of-view it is one of the most important variables to consider.
- Movement Ratio
- (This can be either from the wheel to the damper (spring) assembly or to an anti-roll bar. The geometry of this will determine how quickly the car will respond to bumps, corners etc. It is used in calculating spring and anti-roll bar rates.
- Oversteer
- This is when the back of the car slides out before the front. A combination of throttle and steering adjustments is used to control it. Most often experienced on rear-wheel drive cars.
- Roll Centre
- Roll Centre is the theoretical point around which the chassis rolls in cornering and one can be found at each end of the car. Nowadays we tend to keep these fairly low in order to prevent a condition known as 'suspension jacking'.
- Roll Stiffness
- This is the stiffness a chassis has to oppose cornering forces. The lower the stiffness, the more the chassis will roll in cornering.
- Scrub Radius
- Also known as the king-pin offset, this is the distance from the centre of the tyre to the point where the king-pin axis intersects the ground. If very large, it can cause the steering to 'snatch' under heavy braking.
- Toe / Tracking
- It is important to minimise tyre wear whilst aiding steering and straight-line stability. It also helps to take up any slack in the suspension / steering joints that may be present.
- Torque Steer
- Torque Steer is mostly found on powerful front and four-wheel drive cars. If excessive, the drive train tends to wrench the wheel from the driver's hands. It can be controlled with a special steering/suspension geometry setup.
- Understeer
- Mostly found on front-wheel drive cars (especially early Minis etc). It's when the front of the car slides wide in a corner as if you'd just hit a patch of ice. Advanced rally-driving techniques use left-foot braking to help lessen this effect and keep speed up through the twists.
- Unsprung Weight
- This refers to the parts of the chassis that aren't "sprung", for example the wheels, brakes, suspension components etc. For optimum handling, keep these as light as possible within the bounds of stiffness and strength.
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