Live Axle

A live axle, sometimes called a solid axle, is a type of beam axle suspension system that uses the driveshafts that transmit power to the wheels to connect the wheels laterally so that they move together as a unit.

A live axle consists of a central differential in a single housing that also contains the driveshafts that connect the differential to the driven wheels. The differential is connected to the engine via a swinging drive shaft and a universal joint. The complete assembly may typically be suspended with leaf springs, coil springs or air bags.

Live axle front suspension

Trail Braking

Trail braking refers to continuing to brake past the turn in point, and on into the corner.

Generally a driver will get all the braking done before turn in so that all the tires grip can be used to corner the car. Trail braking or having the foot trailing the brake pedal (coming off) as the car is turned will help the car pivot on turn in.

This is an advanced technique as it involves making the tire’s contact patch attempt to both continue slowing the car as well as turning into the corner. This makes it easier to over drive the corner, and lose time or positions in a race.

Weight Jacker

Weight Jacker

The weight-jacker is a setting somewhat akin to wedge on a stock car. The main difference is that the driver can adjust weight-jacker while on the track. There are even rumors of some drivers adjusting weight-jacker in between corners to get the most out of a lap.

Increasing weight-jacker makes the car looser. The weight-jacker goes from -15 to 15. Bear in mind that the setup keeps the last weight-jacker settings and can cause a setup to fail tech in the garage.

I try to get the car setup to where it’s a smidge free with the weight-jacker set to 0. When I leave the pits or at race start, I’ll set it to -1 to add a little push to the car for the first lap while the tires are cold.

Important to note that just 1 click of weight-jacker can have drastic effects on the amount of over/ understeer in the car. It’s a brave soul who will click it more than once at a time.

Tire pressures

TirTire pressure gaugee pressures

The Tire acts as a spring, with softer tires generally offering increased grip. The aim is to have somewhat even tire temperatures across the tires.

On cars that don’t have suspension adjustment, you can adjust the balance with a change in tire pressures.

For example; take a car that is pushing or under-steering out of the corner.  Lowering the front Tire Pressures and/ or raising the rear Tire Pressures, will help cure the problem.

I have some further thoughts on tire temps with regards to camber etc … more to come after further testing.

 

 

Brake Bias

Brake Bias

A race car typically has two master brake cylinders. One controls the front brakes and the other the rear. A dial between the two controls how much pressure goes to each.

This allows the driver to change the balance of the brakes. If the front tires are locking up too easily, you can move the balance to the rear somewhat to help.

Locking up the rears usually leads to a quick swapping of ends and the air being filled with expletives.

While a rearward bias will help you turn the car getting into the corner, too much will lead to bad things.