Practical Corner Weighting: Car Balance and Predictability - Performance
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Car Balance and Predictability - Performance
05.44
| 00:00 | - Now that we've covered the key topics of corner weighting and balance, we're going to focus on the main handling characteristic of a well balanced car and what you should watch out for if your car isn't well balanced. |
| 00:11 | I should probably mention that you are unlikely to experience the same car behaviour on the road as you would on the track so making changes to your corner weights might not come across as obvious, when driving your car on the road. |
| 00:24 | What you will find out on the track however is with a better balanced car, you'll have much more confidence when attacking corners, which will allow you to push the limits further without feeling like you're on the edge of losing control. |
| 00:37 | We can essentially break handling characteristics down into three topics, braking, acclerating and cornering and quite often you'll be mixing cornering with accelerating or braking at the same time. |
| 00:50 | Let's start off by looking at braking, in a perfect world, a car with a 50/50 left to right balance will always brake in a straight line, assuming that the road surface is level and flat and that your brakes and wheel alignment have been set correctly. |
| 01:03 | The theory here is that the more load the tyre applies to the ground, the more grip it will have, provided that we're within the working range of the tyre and it's not overloaded. |
| 01:13 | If our corner weight is slightly off balance, let's say 55%, then the car will have more grip on the right hand side than the left and it won't be able to generate as much braking force on the left hand side. |
| 01:24 | We'll be able to feel this through the steering wheel, as the steering wheel will pull to the right. |
| 01:29 | Another great way to notice if your car is unbalanced is if you constantly find that you're locking a certain wheel under braking in a straight line. |
| 01:37 | For example if the right front tyre is constantly locking and assuming your brakes are functioning correctly, then this would mean that there's more weight over the left hand front tyre and this needs to be balanced out by adding weight to the right. |
| 01:49 | Of course this is only relevant if you're braking in a straight line though and if you're running equal camber on both sides of the car too. |
| 01:57 | To illustrate the importance of the balance of the braking performance, Jota Sport who run the Oreca LMP2 chassis found that the car will suffer from wheel lock up on one side of the car if the left to right weight balance on the front axle line is out by more than 2 kg. |
| 02:14 | Moving on, acceleration is slightly more complex than braking, given that we may be running given that we may be running a front wheel drive, a rear wheel drive or a four wheel drive car. |
| 02:23 | However we still want the car to accelerate in a straight line as much as possible. |
| 02:28 | Having an unbalanced car can make the car pull to the left or the right during hard acceleration so this can be a clue that our corner weights need attention. |
| 02:37 | This follow the same principle as braking where if you have more weight on one side of the car than the other, you're going to have more force acting downwards on that tyre causing more grip compared to the opposite side. |
| 02:50 | Of course in this instance we do also need to consider that powerful cars can exhibit a tendency to torque steer so not all evils in this department can solely be attributed to corner balance. |
| 03:02 | Lastly we can move onto cornering. |
| 03:04 | Again you can look at the two mirrored corners as discussed in an earlier module. |
| 03:09 | If we assume that you take the same racing line through each corner at the same speed, then ideally we want the car to react and handle exactly the same in both the left and right hand corners. |
| 03:21 | This makes it much more predictable when driving. |
| 03:24 | A sign that a car is not well balanced will be that the car tends to turn better in one direction than the other or exhibits more grip. |
| 03:32 | The best way to notice a different in handling will be through observation and testing on track. |
| 03:37 | If you find that the car constantly feels neutral and predictable in a left hand corner but consistently oversteers in a right hand corner of a similar radius and speed then the first thing you should be checking is the corner weights. |
| 03:50 | As mentioned, achieving better corner balance will definitely have a positive affect on the consistency of your driving as well as improving the life expectancy of a variety of components on the car. |
| 04:02 | As I mentioned in the previous module, if you have a 50% cross weight then the car will handle similarly in left hand and right hand corners so let's consider the parts of the car which could be affected by poor balance. |
| 04:16 | Firstly we should look at the tyres, if the car is off balance and putting more pressure into one specific corner repeatedly during a race or a long track session, then this corner will tend to wear faster than the others. |
| 04:29 | Visually, you'll be able to see this on the tyre and what I mean here is that the tyres will have a wear pattern that will be different from the left hand side of the car to the right hand side. |
| 04:39 | Of course we need to consider that in a clockwise racetrack configuration we could expect the tyres on the left hand side of the car to wear more than the right since the car will turn right more than left, so some common sense still needs to be applied to analysing aspects such as tyre wear. |
| 04:56 | A difference in tyre wear can becomes increasingly important in endurance style races where you want the tyres to last as long as physically possible. |
| 05:05 | In close connection to the tyres are the brakes. |
| 05:08 | Again a weight imbalance here will cause increased brake wear and will reduce brake life throughout the race. |
| 05:16 | This can also be noticed by uneven wear on a particular corner of the car but as with tyre wear, there are other potential contributing factors to brake wear, so corner weighting might not be the only solution. |
| 05:28 | The other thing to consider here would be chassis components such as bushings, wheel bearings, CV joints and any other parts that move when the car is under load. |
| 05:37 | Repeated use on an unbalanced car can cause accelerated wear. |
