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Understanding Suspension

by Estelle Nagel
Understanding Suspension

Thump. We’ve all missed spotting that speed bump or pothole in time to brake during our motoring journeys. Your ego takes a bruising, but spare a thought for your car’s suspension. Not only does it have to deal with bumps and holes in the road, it must also provide your car with satisfying handling dynamics.


The theory behind suspension is more than 100 years old, but engineers are still fine-tuning the hardware and adding technology to improve vehicle performance. Since the days of horse-drawn carts, designers have striven to isolate the passenger compartment from road imperfections. Initially, they suspended the cabin on top of the fixed-cart chassis using leather straps. Oh how far we’ve come…

Automobiles isolate the cabin by allowing the wheels to oscillate and, to achieve this, several suspension configurations are employed. Bumps in the road are essentially forces acting on the wheels in a vertical direction. To provide a smooth ride, the suspension must absorb the vertical displacement of the wheel while dissipating the energy of the moving components. For handling performance, it is important that the tyres maintain an optimal contact patch on the road because this is where cornering forces are generated.

A good suspension system allows the tyre to stay in contact with the road surface under most road conditions. The vertical orientation (camber) of the wheel is important during cornering, as vehicle body lean or weight transfer skews the contact patch and negatively impacts the maximum lateral force. Here, suspension geometry plays a vital role.




Springs: These store the kinetic energy generated by the wheel’s upward movement and release it by exerting a force in the opposite direction of the spring compression. This force is proportional to the displacement of the spring and not the speed at which it’s displaced. A softer spring rate results in a comfier ride, but it can compromise the vehicle’s body control, especially during cornering.

A stiffer spring rate results in better body control (or load-carrying ability in commercial vehicles), but affects the ride quality. The springs’ secondary function is to support the vehicle-body mass and set the correct ride height. The types of springs include coil, leaf and air units.


Anti-roll bars: When a vehicle corners, weight transfer compresses the suspension on the outside wheels just as the suspension on the inside wheels is extended. This is especially true if the vehicle is fitted with independent suspension and has a high centre of gravity. The resultant body roll has a negative impact on handling and wheel camber relative to the road surface. Fitting an anti-roll bar minimises this movement.

The bar is a mechanical device in the shape of a “U” and runs between the suspension components of both the wheels on a single axle. The compression of one wheel on the axle results in a torque moment in the anti-roll bar that also tries to compress the other wheel’s suspension. As a result, the vehicle stays flatter in corners.


Shock absorbers/dampers: These items dampen the body oscillations relative to the wheels when crossing undulations. That’s why they’re also called dampers. Shock absorbers provide a resistance force in the opposite direction of suspension movement. The key fact is that the force is proportional to the speed of the movement and not the displacement. So, you can easily compress or extend a shock absorber if you do it slowly. The contrary is true if the operation is repeated at speed.

Without shock absorbers, a vehicle continues to bounce after hitting a speed bump. The shock absorber dissipates the kinetic energy (mostly through heat) and stabilises body movement.


Most suspension systems are reactive and respond to a road imperfection or bump only once it has been hit by the wheels. Future technology will employ active suspension where a camera (and/or radar) scans the road surface ahead and primes the suspension. Mercedes-Benz’s Magic Body Control is an example of such a system; it adjusts the damping on each wheel in a fraction of a second to compensate for speed bumps – even when you don’t see them.

Land Rover is working on a similar system, but has taken it a step further. The scanned road information is uploaded to the Cloud where all other vehicles can benefit from the GPS-based information, altering their suspension settings for a certain road. Active suspension also allows the normally mutually exclusive suspension characteristics of sporty handling and comfort to merge into one setup…

For more technical features, head on over to our friends at CAR Magazine.




by Estelle Nagel

65% of cars driving on South African roads are not insured. That’s two out of every three vehicles.

Jeff Osborne, Head of Gumtree SA Automotive, says that, without insurance, any accident can leave the car owner badly exposed financially and possibly legally as well. He urges all drivers to get some form of cover especially as there are policies available with monthly premiums at less than R100.

Osborne highlights three key factors in choosing the right kind of vehicle insurance; “what you can afford, the value of your car and your driving patterns”.

He says the last of the three involves “assessing the amount of driving you do and where you usually do it in order to get an idea of the likely risk of an accident”. He adds that where the vehicle is parked, both at home and at work, is a further important consideration especially when assessing theft cover.

Osborne explains that there are three basic types of car insurance options in South Africa, each suiting different needs.


By far the cheapest option. It covers damage to another vehicle and the accidental death or injury of third parties. It does not insure against loss or damage to your own vehicle.

Who should use it? Anyone whose car is old, completely paid off, rarely on the road or who cannot afford a higher premium.


This adds cover of your own vehicle against theft or fire damage to the basic third party cover of damage to another vehicle or injury to third parties. This option can also cover certain accessories like windscreen, radio or canopy.  It does not cover against any accidental damage to your own vehicle.

Who should use it? Ideal if you owe very little on your car but can afford a slightly higher premium especially to provide cover against theft.


The most expensive but also the most extensive cover protecting you in the event of theft, hijacking, damage caused by accidents, as well as fire and natural disasters like hail. Depending on the insurer, this cover could offer additional benefits like roadside or medical assistance, replacement car hire, towing and storage.

Who should use it? Anyone who can afford it and who has an expensive vehicle and/or a significant amount owing on the vehicle or who does a high amount of mileage in higher risk conditions.

Insurance 101

by Estelle Nagel
Insurance 101

In South Africa there are various forms of car insurance, each with pros and cons. What are they, and how do you make sense of it?

If you buy a car that is financed, your financial borrower will insist on insurance as technically the financial institution owns the car until it is fully paid off. If you buy privately and pay in cash, the onus is on you to take out insurance, or not…



A South African reality is that around half of all cars on the road have no insurance cover.

First and foremost, insurance is there to take the financial risk off your shoulders to cover all costs related to the accident. Should you be involved in an accident and have no cover, you are liable to fork out the costs for repairs not only to your own car, but any other party involved in the accident.

If you cannot afford to repair your own car, you will be without transport, and what if you run into a Rolls-Royce or a Ferrari – you could lose your house or go bankrupt in paying for those repair costs, as the owner of that car (or its insurer) has every legal right to sue you for damages incurred.

Should you take out no insurance cover whatsoever, you might want to re-think your strategy.



This is the cheapest form of insurance. It covers the costs of other parties you may have an accident with, but you are still liable for repairs costs to your own car. This way, the Rolls-Royce and Ferrari are covered should you be responsible for its damage.



The same as above, but the insurer will pay out should you lose your car through accidental damage such as a fire, or if your car is hijacked or stolen.



Obviously the most expensive form of insurance, but this time your insurer will pay out for damages to your own car as well as that of other parties involved in the accident. Your insurance premium will be determined by our excess amount, which you can negotiate with the insurer – the higher the excess fee, the lower the premium, and vice versa.

Always keep a ‘rainy day’ fund so you can at least cover the excess amount when the need arises.

Dreaded Increases.

by Estelle Nagel
Dreaded Increases.

It happens every year: the dreaded increase in premium at the anniversary date of your car’s insurance policy. Most people hardly take note of this, discard the formal notification and accept it as a fact of life.

But next time this happens, take a moment to have a closer look at the numbers. Do some calculations. Determine how much the increase is – 5, 10, 15 or even 20% or more? Since the value of your car this year is 10 or 15% less than last year, premiums should actually decrease, right?

First of all, do an online comparison (like on www.hippo.co.za) and see what your specific car and your personal circumstances will cost in premiums. Hippo kicks out rates from up to 20 individual insurance companies, and chances are that your current insurer will be among them. What will your insurer charge you if you were a new client that very day – more, or less, than currently? Are other insurers cheaper, and what do the excess fees look like?

Armed with this information, jump on the phone, call your insurer and state categorically that you are not satisfied with an exorbitant increase in fees on a car that has declined in value, and that Insurer X or Y has lower fess than you pay currently.

Your insurer may cite inflation costs and other reasons to justify the increase, but you may be surprised that it may impose a really minimum increase – if at all, even offer to waive the excess entirely if you have been a long-standing client – by simply making a fuss about it.

It pays to ask. If you don’t, you’re the only one losing out.



by Estelle Nagel

43,000 claims made to car insurers each year are either partly or fully rejected because of policy exclusions or a breach of conditions.

Jeff Osborne, Head of Automotive for Gumtree SA, says: “Not knowing exactly what your monthly premium covers is dangerous and can be costly”.

To avoid your accident claim being rejected, meticulously go through your contract before signing on the dotted line, warns Osborne: “this attention to detail will save you time, money and a lot of frustration”.

He says there are many reasons why claims get knocked back by insurers but the five main ones are:

  1. An unlicensed driver was behind the wheel.

Letting others drive your car is your choice. But if they’re involved in any accidents while behind the wheel and do not hold a valid driver’s license, your insurer will not cover the cost of the damages.

  1. The vehicle wasn’t covered for a write-off.

If you are victim of an extremely bad accident and your car is a write-off, your insurer will only be liable if write-off cover is explicitly stated in your contract.

  1. The vehicle has not been roadworthy approved.

Your wipers seem minor things but are an integral part of roadworthy requirements. If you are in an accident and it was caused by vision being obscured due to wipers not working properly, the insurer can kick your claim to the kerb.

  1. The vehicle inspection was not conducted.

When opting for a car cover, the insurance company needs to inspect the car. If this inspection is not completed, the insurer will not be able to validate your claim for anything.

  1. One too many after-work drinks.

If it is discovered that alcohol was the cause of an accident, any related claim will automatically be rejected. Do not drink and drive.


by Estelle Nagel

Comic books are serious business.

Conrad Vosloo of Kraaifontein has around 300 comic books listed on Gumtree, South Africa’s biggest online trading site, and says he’s contacted by interested buyers almost every day.

He has been trading them for over four years now; “I started buying and selling anything that I could make a profit from – watches, furniture and other bits and bobs – but when I saw the amount of money there was to be made in comics, I started to specialise.”

The world’s most expensive comic was sold for $3.2 million (R48m) on eBay, Gumtree’s sister site in the USA. It was an original copy of Action Comics #1, which introduced the world to Superman and originally cost just 10c.

Claire Cobbledick, Head of Marketing for Gumtree SA, offers six tips for getting the best price for comic books on Gumtree.

  1. Know Where To Look – browsing comic price guides online can give you an idea of what your comics are worth.
  2. Know the Condition – creases, yellow paging and marks all affect pricing. The better the condition, the higher the price.
  3. Take Your Own Photos – using your own images when uploading your comics for sale online will generate more interest than an ordinary google image.
  4. Give Proper Descriptions – when searching, collectors look for very specific comic editions. Ensure that you include the title, issue and volume number, publisher, story arc as well as characters mentioned in that specific comic.
  5. Sell Collections Together – selling a collection attracts bidders and gives the potential buyer the impression of a bargain.
  6. Be Tactical – when the new Avengers movie was released, thousands of comic book iterations popped up all over the net. Buyers paid extreme amounts for them.


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