Why do racings cars have low centre of mass and widely spaced wheels?

Question

Engineers design racings cars with low centre of mass and widely spaced wheels to improve their high speed cornering ability. Explain using moments, how this helps.

Answer 1

This probably would've fit better into an engineering section.

The low centre of gravity is to reduce the effect of "lift" that the car would experience going at such high speeds. Also, combined with the widely spaced wheels, the car will get better traction around corners and won't drift as much.

Answer 2

to reduce weigth shifts from wheel to wheel.

load shift is proportional to CG height and to the inverse of the wheel spacing.

Load shifting from one tyre to another is a bad thing because of something called "load sensitivity" in tyres. The more load you have on a tyre the less lateral and longitudinal force that tyre is able to generate.

In numbers, imagine to have a car that has 200kg on both tyres at the front.
Let's say the tyres can generate 1.5g of lateral force you will get a potential lateral force for each tyre =

LF=200*9.8*1.5=2940 N

For a total axle lateral force of 2940*2=5880

Now imagine to negotiate a turn that will move say 60kg from the inner tyre to the outer tyre we'll have 260kg and 140kg on each tyres. Let's say load sensitivity will bring the loaded tyre coefficient down to 1.3g and the unloaded tyre up to 1.8g.. calculate again:


LF=260*9.8*1.3=3312 N (outer tyre)
LF=140*9.8*1.8=2469 N (inner tyre)

In this situation the TOTAL axle lateral force would be 5781 N.. thus lower than the 5880N that the axle was generating with even load distribution.

This is also the reason why anti-roll bars work the way they do..but that's another story.. bottom line, lower CG and wider wheelbase/track means less load shift.. less load shift equals more grip.

Answer 3

The lower the centre of mass the smaller the risk of rolling over in a tight turn.

Answer 4

so when they take a turn at high speeds they do not role over

Answer 5

So they don't roll in a turn. It's more stable, and provides better traction.