Wheel and Tyre Fitment: Camber & Camber Gain
Watch This Course
$99 USD
-OR-
Or
8 easy payments of only $12.38 USD
Instant access. Easy checkout. No fees.
Camber & Camber Gain
05.24
| 00:00 | The dimensions we've discussed so far in this section of the course have been specifically related to the geometry of the wheel itself. |
| 00:08 | Camber and camber gain on the other hand is related to the suspension geometry, although it'll have a big influence on the fitment of our wheels so it needs to be discussed. |
| 00:19 | Information on suspension has been pretty thin so far in the course. |
| 00:24 | So, first we need to cover what these terms actually mean. |
| 00:28 | Camber is the angle between the centreline of the wheel and the vertical axis when viewed straight on. |
| 00:35 | If the top of the wheel is further outboard than the bottom, this is referred to as positive camber. |
| 00:40 | However, for performance applications, we almost always tend towards a small amount of negative camber where the top of the tyre is tilted inwards. |
| 00:50 | The basic reason for this is around optimising the tyre contact patch as the vehicle moves around a racetrack, particularly when the car is cornering. |
| 00:59 | But what's important to our conversation is how the clearance to the guard changes with camber. |
| 01:05 | Basically, the more negative camber, the further the top of the wheel moves in, and therefore the more clearance to the guard, all other things equal. |
| 01:14 | Static camber describes the camber angle as the vehicle sits at ride height. |
| 01:19 | In some factory vehicles this is adjustable, although usually fairly limited. |
| 01:25 | But with parts like adjustable control arms and top hats, we can dial this in a lot better. |
| 01:30 | This is usually in the range of 0 to 5 degrees, or a bit more depending on the tyre application and suspension geometry, among many other things. |
| 01:41 | There are some other aspects to consider here, such as suspension geometry that promotes negative camber gain as the suspension compresses into bump travel, or the steering wheel is turned. |
| 01:54 | This means that we can run less static negative camber in a straight line, but still achieve optimal tyre contact patch when the suspension compresses and the steering wheel is turned into a corner. |
| 02:06 | If you're interested in learning more about this, I'd highly recommend checking out our suspension tuning and optimisation course, as well as our motorsport wheel alignment course linked below this module. |
| 02:17 | To understand why this is important for wheel fitment, let's use an example of a simple McPherson strut to start with. |
| 02:25 | If we have a wheel with a certain diameter, width and offset, and a running zero static camber, as the suspension compresses over a bump, or through a corner, the wheel moves upwards towards the guard. |
| 02:39 | At the same time, the camber will change by some amount due to the lower control arm moving in an arc. |
| 02:46 | If there is an increase in negative camber, there will be more clearance to the guard, and an increase in positive camber would leave less clearance. |
| 02:55 | With a McPherson strut, the change in camber is usually relatively little, and for stock vehicles at stock ride height, it's normal to see a slight increase in negative camber at the start of the bump travel, followed by the wheel moving into positive camber at the upper end of the travel. |
| 03:13 | This is why lowered cars that are operating in this upper range of travel can gain positive camber in bump travel, which in the context of our discussion, would mean the top of the wheel moves towards the guard. |
| 03:27 | Running more static camber will increase the camber by the same amount all the way through the travel. |
| 03:33 | Alternatively, if we consider a double wishbone suspension layout, specifically with a shorter top wishbone than the bottom, the wheel will, generally speaking at least, gain more negative camber as it moves through bump travel. |
| 03:48 | This means that if we start with zero static camber at full travel, there will be more clearance to the guard, potentially meaning we can run a wider and or lower offset wheel. |
| 03:59 | This isn't to say that one suspension design, like a McPherson strut, can't have more camber gain than another, like a double wishbone layout. |
| 04:08 | So, at the end of the day, it really depends on that specific geometry for that vehicle, not just the type of design, and we'll be covering how to check for clearance with this taken into account in the practical skills section. |
| 04:22 | With all of this said, it's easy to see why it can be tempting to run excessive static camber to make a set of wheels fit that otherwise wouldn't, and in some cases, this is an aesthetic choice. |
| 04:35 | However, it's clearly not the ideal way to go about things if our priority is performance. |
| 04:40 | A better approach would be to understand the wheel size that would fit, given the approximate amount of camber you plan on running, as well as the camber gain of your vehicle before purchasing wheels. |
| 04:53 | The key point to remember here is that the amount of camber we run has an effect on the wheel clearance, where more negative camber will provide more clearance, and therefore the potential to use wider and or lower offset wheels. |
| 05:07 | The amount of negative camber we have throughout the suspension travel is a factor of the static camber and camber gain, but this should be tuned and optimised for performance, rather than to make a set of wheels fit. |
