Suspension Tuning & Optimization: Different Suspension Types
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Different Suspension Types
04.39
| 00:00 | - There are a huge number of suspension configurations that different road car manufacturers use. |
| 00:05 | And as we spoke about in the previous module, their decisions are generally guided by things not related to pure performance. |
| 00:12 | This won't be an exhaustive list of all the possible suspension configurations but more of a summary of what you're most likely to come into contact with when modifying a road based car for competition. |
| 00:24 | These configurations have their own strengths and weaknesses that are important to understand and we'll be discussing each as we go. |
| 00:31 | As we learned in the last module, priorities for road cars typically include low cost, being easy to mass produce, packaging to maximise interior space and passenger comfort. |
| 00:42 | For the most part, none of these factors are particularly important to us in motorsport. |
| 00:46 | One of the most common suspension types you'll find in road cars, particularly in the front is the MacPherson strut. |
| 00:53 | The upright or hub is rigidly attached to the strut and will have a single lower control arm attached by a ball joint or spherical bearing. |
| 01:02 | In this arrangement, the damper body makes up one of the main locating components of the suspension. |
| 01:08 | Pros include low cost and ease of manufacture as well as being relatively compact. |
| 01:13 | Cons include low stiffness to weight ratio, stiction as the result of the applied side load to the damper, and poor camber recovery in roll. |
| 01:22 | Camber recovery refers to the amount of camber gain the wheels have as the chassis rolls. |
| 01:28 | No camber gain would mean the camber of the tyres doesn't increase as the suspension is compressed, which isn't ideal for most types of competition. |
| 01:36 | In general terms, while a MacPherson strut can be made to work somewhat adequately, it's not well suited for motorsport use. |
| 01:44 | Next, let's take a look at multi link suspension. |
| 01:46 | In its simplest form, this is made up of two force members meaning each link is purely in tension or compression with no bending forces. |
| 01:56 | There are a number of different potential layouts which can include as many as 5 individual suspension members. |
| 02:02 | Pros include high flexibility of the kinematic design, giving the designer control over things like camber curves, toe change and roll centre location as well as some packaging flexibility. |
| 02:13 | Some cons are the high manufacturing costs and complexity as well as a challenging design and modelling process. |
| 02:21 | A multi link can be suitable for motorsport with some modifications from the factory layout. |
| 02:27 | Double wishbone suspension is another common system in modern vehicles. |
| 02:30 | And is primarily made up of an upper and lower control arm to locate and control the motion of the upright. |
| 02:37 | Strictly speaking, the double wishbone is a sub type of a multi link suspension but it's such a popular layout, it's worthy of its own discussion. |
| 02:46 | The name comes from the general shape and top down view, resembling the shape of a wishbone. |
| 02:51 | A coilover unit will generally be attached to either the upper or lower control arm which is referred to as direct acting. |
| 02:58 | Another option would be indirect acting which is uncommon in road cars. |
| 03:03 | This is where the coilover is mounted inboard and is actuated by a system of push or pull rods and a rocker. |
| 03:10 | Double wishbone pros include being highly configurable to the required kinematics, good camber recovery and roll and a high stiffness to weight ratio. |
| 03:19 | On the downside, the system does tend to take up a lot of room which can be a challenge for packaging. |
| 03:25 | It's also expensive and time consuming to produce. |
| 03:29 | Overall though, a double wishbone suspension is generally an excellent choice for motorsport use. |
| 03:34 | Lastly, live axles aren't something that you see too much these days. |
| 03:38 | But it's still worth looking at because they were still in widespread use in some sports cars up until the 1980s. |
| 03:44 | This suspension consists of a rigid connection between both wheels and is typically found in the rear of rear wheel drive cars. |
| 03:51 | WIth the differential being integrated as part of the suspension. |
| 03:55 | Pros include relatively low cost and no camber change and heave but the cons for a live axle are big. |
| 04:02 | There's extremely high unsprung weight, the lack of independence of the suspension from one side to the other and zero camber recovery in roll. |
| 04:11 | In summary, while there are many types of suspension available on road cars, the ones that we've covered here are the most common. |
| 04:17 | Each has their own pros and cons. |
| 04:20 | Unless you're interested in making significant changes to the way your suspension works, you're going to be largely stuck with a suspension type that the original designers chose for your car. |
| 04:30 | But with that said, there's always plenty of optimising to be done, no matter what suspension you're working with. |
