What is Suspension?

Suspension is the term used on vehicles that mounts onto the four corners where the wheels are based. Suspension usually comes in Shock and Spring form however different types and designs have been implemented over the years, each designed to have slightly different uses.

What does suspension do?

A vehicles suspension is designed to carry the weight of the vehicle and allow movement whilst in motion. Suspension also plays a big part on the handling of your vehicle.

How does Suspension work?

Suspension works by allowing movement to happen whilst the vehicle is in motion. This movement is normally controlled by coil springs, fluids, flexible metal, bars or compressed air. Suspension is also used to keep your vehicle form scraping the ground by suspending the weight of the vehicle evenly.

So what are the different types?

As mentioned further up, there are a few different types of suspension which is most commonly used on the roads. They are listed below as follows, Please click on each types for more information:

* Shock and Springs
* Torsion Bar
* Dampers
* Coilovers
* Airbag
* Hydraulic
* Leaf

So what can I do to modify my suspension then?

Generally there are a good few options for each vehicle available but you can uprate your suspension to make your ride higher or lower, stiffer or softer on ride handling or move up and down at the simple flick of a switch!

On each of the above we have mentioned in more detail how each type works and its advantages and disadvantages to Modifiying them. Please click on each type for more information.

The Law on Suspension:

There is no law to state that Modifiying your suspension is illegal however a ride that is to low that it either A, allows the wheels to foul the bodywork or B, disallows an MOT tester to drive it onto a ramp will find itself with a failed MOT ticket, so becareful!

What are Shocks and Springs?

Shocks and springs are the most common suspension setup found on cars to date. The shock is the strut setup that has a fluid fed ram that adjusts under pressure. The spring sits within the strut on a specilay crafted housing, the spring controls the ride height and firmness by the amount of full coils and bounce-ability (quality).

What do Shocks and Springs do?

As described in "What are Shocks and Springs?" the shock and spring combination control the movement of uneven road surfaces etc to help prevent an uncomfortable ride. The metal coil spring flexes and as a result dampens the harshness of speed bumps and other uneven road surfaces.

So by modifying my Shocks and Springs what am I doing?

A common modification on cars is to modify the suspension, this is usually to improve the ride quality, height and handling.

The term "lowered" comes from modifying the suspension ride height and is a very common modification for cars. To lower a car you replace the exisiting springs with a set of specialy crafted lowering springs that have less coils and are more compressed to still allow for the ride handling and weight control. Lowering springs start at around 15mm and go up to around 80mm if not more.

This setting is the amount lower than the stock springs your ride will sit. For example a set of 30mm lowering springs will lower your ride 30mm lower than the standard stock springs.

Its good to note that a lowering spring kit that exceeds 35mm usually requires uprated dampers to be purchased aswell. This is simply to do with the fact that the stock dampers are not designed to work with such a short or highly compressed spring and really effects the performance of your suspension - meaning a bumpier more uncomfortable ride than need be.

By lowering your ride you are not only improving the stance of your vehicle you are alos improving the ride quality and handling performance. A lower car hugs the road better and in some cases helps that "go-kart" feeling when driving on the roads.

The Law on Suspension:

There is no law to state that Modifying your Shocks and Springs is illegal however a ride that is to low that it either A, allows the wheels to foul the bodywork or B, disallows an MOT tester to drive it onto a ramp will find itself with a failed MOT ticket, so be careful!

What is a Torsion Bar?

The torsion bar is basically a spring but with a slightly different shape to the spring you'd normally see. The idea of a torsion bar is one end is fastened to the rear axel frame of the car and the other is attached to the control arm of the vehicle.

As the control arm moves with the road surface the torsion bar tries to move wit it but it cant due to being fastened at one end. When this happens it causes the torsion bar to twist and distort creating movement. Once the pressure on the torsion bar is release it then tries to twist back into place creating the movement process.

It sounds very technical and advanced compared to the usual spring setup but that's because it is. Torsion bars are usually used on heavier duty vehicles, this is unless your car is French of course. The French tend to use torsion bars on most of their vehicles no matter how big or small it is!

So by modifying my Torsion Bar what am I doing?

If you have a vehicle with a torsion bar and you are thinking of lowering your ride then its worth knowing what it is exactly what you are about to do. The torsion bar needs adjusting (or "reseting") to a new level.

To adjust the ride height you need to wind the adjuster bolt at the fixed end of the torsion bar so this does not add any more force to the pivoted control arm end of the torsion bar, meaning the ride quality is unaffected. Winding the torsion bar adjuster bolt is the same as installing blocks between the axle and leaf springs or a set of coil spacers, it simply moves the spring to a different position.

So how do I lower my Torsion Bar then?

Now then, lowering a torsion bar is not impossible nor is it impossible for you to do at home on your driveway however there are a few things you do need to know.

1. You need a slide hammer. These are not the easiest tools to get hold of, nor are they cheap.
2. You need to know how to use a slide hammer. Yet again not easy first time round, slide hammers are crazy tools that don't take to long to get over excited with them and end up breaking something so please, please do not use it first time round on your brand new cars suspension.
3. You need to know how a torsion bar works. Fair enough we've just told you this but its not a simple as the abc. Torsion bars are tricky, you need to measure how much you are twisting and how far you are twisting it on each end as otherwise you'll end up with wonky suspension.
4. You need to e aware that Torsion bars seize quite easily.

It doesn't take that long at all for a torsion bar to seize up and unless you are aware of the symptoms of a seized torsion bar you could end up in trouble! Things have a tendancy to snap or break if your torsion bar has seized up and you apply to much pressure, then your stuck with a broken car with a seized up torsion bar stuck inside. Not Good.

What advantages and disadvantages does lowering my Torison bar have then?

Advantages: if your lowering your torsion bars hen the chances are that you want to lower your car a bit. The handy thing with torsion bars is one you've released the bar you can adjust them as far as you want, and that means to the floor if you want to. This is normally where the term slammed comes into play but do remember that speed bumps don't go down to well with slammed rides!

Disadvantages: By lowering your torsion bar you are decreasing the amount of play in your suspension, this now means the ride is less comfortable and a heck of a lot tighter than it used to be. Going full hog and slamming could also get you into trouble too if you haven't thought it out, it will only take you on attempt at a hard speed bump to ruin you whole suspension if you do it worng!

What to remember about Torsion Bars:

Torsion bars are deceiving objects. They leave you in control of your own ride height so play carefully. If you are in any doubt then please leave it and take it to the professionals. The average cost is £100 to lower your torsion bar evenly on both sides so its not as expensive as a new car. The professionals use high tech equipment and generally have experience of setup similar to yours on a day to day basis so for the £100 odd it costs, its worth every penny!

The Law on Torsion Bars:

There is no law to state that Modifying your torsion bars is illegal however a ride that is to low that it either A, allows the wheels to foul the bodywork or B, disallows an MOT tester to drive it onto a ramp will find itself with a failed MOT ticket, so be careful!

What is Hydraulic Suspension?

Hydraulic Suspension or "Hydraulics" for short is another form of suspension setup for modern day road vehicles. Unlike other suspension types Hydraulic Suspension uses four independent dampers filled with Hydraulic fluid which are controlled by a main control unit, normally found inside the vehicle.

What does Hydraulic Suspension do?

The four dampers in the Hydraulic System are individually controlled by a main control unit which allows each damper to be pressurized and de-pressurised to allow a sudden up and down movement at the flick of a switch.

That simply means you can move each individual shock up and down as much or as little as you like by pressing a few buttons. As you can imagine, this is why Hydraulics are so popular in the Modified car world.

Is Hydraulic Suspension available for all ride types then?

Tricky question there. Most Ride types will allow a Hydraulic Suspension setup to be installed but due to the difference in suspension types it can be tricker on certain ride types. The Hydraulic Suspension kits are a universal kit that can be tailored to fit your vehicle however if you have for example rear torsion bars or leaf suspension these will need adjusting or modifying to make the Hydraulics work to the maximum effect.

Sounds Great, so how do I fit them to my ride then?

Fitting a hydraulic suspension kit isn't and easy job and does require a vast amount of technical knowledge and experience to get right. As the kits are expensive to buy and ultimately repair if incorrectly fitted it is much more cost effective to have these installed by the professionals.

How much does it cost then?

A typical Hydraulic Suspension kit fitted to your ride with no extra modifications should cost you around the £2000 mark.

What are the advantages of having Hydraulic Suspension on my ride?

The idea of having moveable suspension at the flick of a switch is what sells it to most people but what really makes Hydraulics ahead of the game is the speed it does it and also the fact that each shock is completely independent (depending on the kit you buy obviously). This means that while your back left strut is fully down the back righ could be fully up and the front two half up or half down, what ever you fancy really!

What are the disadvantages of having Hydraulic Suspension on my ride?

The cost of it! Hydraulic Suspension doesn't come cheap and can be very expensive to repair should a kit be fitted badly or incorrectly. You have been warned! Make sure the installer of your kit has plenty of experience with fitting Hydraulics otherwise you may get stung!

The Law on Hydraulic Suspension:

No UK law states that having Hydraulic Suspension on your ride is illegal however it does lay entirely in the hands of your MOT or Vehicle inspector. If for any reason your vehicle runs the risk of causing danger on the roads to you or anyone around you then the inspector reserves the right to deem the vehicle unsafe. This shouldn't effect you if you have had your Hydraulics fitted professionally though.

What is Air Suspension?

Air Suspension is a suspension setup that uses compressed air instead of springs and shock absorbers. Instead the system uses four dampers filled with compressed bags of air and a compressor to compress and decompress the air accordingly.

This type of system is commonly used on buses and heavy loading vehicles and now more commonly on the modified car scene. Air suspension is also known as Pneumatic Suspension or Airbags.

What does Air Suspension do?

The bags of compressed air are stored in each wheel arch with a tailor made damper to position them. The air inside the bags can be compressed or decompressed via the compressor inside the vehicle. This means like Hydraulic Suspension the suspension adjusts up and down at the flick of a switch.

Air Suspension kits for modified cars allow up to a four inch drop at the push of a button. The older type and cheaper kits take a few seconds to fully compress and decompress however a recent new "Fast-Air" kit has been launched to allow fast air movement, naturally these kits are also more expensive.

Is Air Suspension available for all ride types then?

Air Suspension kits are a universal fit and require tailoring to fit each vehicle, not something we'd recommend you doing from home. Vehicle with Torsion Bars and Leaf type suspension alos require extra work for the "Airbags" to work correctly so be prepared if you have either of these on your ride.

How much does Air Suspension cost then?

The cheaper air kits can be picked up for around £700 however fitting also comes in at around the same cost, but well worth the money. The newer type of "Fast-Air" kits normally hit around the £1500 price range with fitting an extra £500 on top.

What are the advantages of having Hydraulic Suspension on my ride?

Its all down to the style factor and practicality in the long run. Airbags are normally a great alternative for anyone that wants that ultimate slammed look when the vehicle is parked up but still wants to be able to drive it on a daily basis.

As we mentioned earlier Air kits can handle a whopping four inch drop from top to bottom, that's a heck of a drop for your ride and all you have to do is pump it up again when you want to drive off!

What are the disadvantages of having Hydraulic Suspension on my ride?

Air kits are more commonly known for going wrong but this is purely down to the way they were installed as opposed to the quality of the kits. Please be careful when choosing who is fitting your kit, make sure they have a long-term history of successful air kit fittings.

The Law on Air Suspension:

No UK law states that having Air Suspension on your ride is illegal however it does lay entirely in the hands of your MOT or Vehicle inspector. If for any reason your vehicle runs the risk of causing danger on the roads to you or anyone around you then the inspector reserves the right to deem the vehicle unsafe. This shouldn't effect you if you have had your Hydraulics fitted professionally though.