Ride height and track width?

[Krispy]

Except the deflection isn't what matters. The spring constant is what matters in terms of lowering tire load variation, and you don't change that (much) by putting on extra load.

Good point, I bet the tyre stiffness does change with the air pressure though. Any folks with Karting experence care to chime in?

[mike]

it could be the case that you want more roll than yaw in the wet since the side on grip is less than in dry conditions, i dont think it will make the car faster, but it will make the car easiser to drive faster

Actually, I'm tall for karts at 1.83 m (6 feet). Just by stretching my spine I can feel the extra grip (extra lever you get, read page 6). On the other hand, by crouching (or, better, by lowering the front ride height), you will take side bite away from the tires and allow them to slide instead of grip. This will decrease the grip in the front-end.

I assume that the extremely low weight of karts has something to do with this "effect".

this is pretty much what happens in bike racing since you are a tall person and i assume weights much more that a shorter person you percentage of weight is greater with the kart, hence if you lean on to the inside it could turn in alot faster and if you CG which is controlable by yourself(stretching your spine)is highter, then the weight transfer will be much greater, and hence even faster in the corners

in bikes lower CG is not always a good thing

[kilcoo316]

Not always true. Haven´t you driven a kart in the wet?
Even in F1 ride hieght is increased for wet weather.

Proof? Source? Other than maybe if they're running softer springs in general and just to offset for how much aero is gonna compress everything.

In many motorsports (with a flat floor), the chassis is raised in the wet to reduce the chances of the floor aquaplaning (note this is distinct and separate from the tyres themselves aquaplaning).

[Shaddock]

With F1 cars its the dynamic ride hide thats important and not the static one. The aim being to reach minimum ride height at the end of the longest straight, whether thats Barcelona, Fuji or Monaco.

[ICA]

Jersey Tom,

When you say that you want as little LOAD transfer as possible, is that to acheive maximum 'grip' or make the car easier to drive?

Thanks,

[connollyg]

Surely the whole point is?

What are the parameters that govern how fast a vehicle can go round a corner, obviously things like tyre friction and CoG are part of that, but what are the the full set of parameters that govern how quickly a vehicle can go round a corner?

G

[Jersey Tom]

Low load transfer (and variation) for max grip.

Ultimate, how fast you go around a corner is limited by how well the tires stick.

[MReggio13]

Remember that with load transfer, you have lost more grip on the unloaded tire than you have gained on the loaded tire. Therefore you have lost overall grip. That is why load transfer is bad. ARB's contribute a massive amount to load transfer, but if you were to run with no ARB, your spring rate would go up to compensate, losing compliance, and also losing grip.

Mike

[Shaddock]

Remember that with load transfer, you have lost more grip on the unloaded tire than you have gained on the loaded tire. Therefore you have lost overall grip. That is why load transfer is bad. ARB's contribute a massive amount to load transfer, but if you were to run with no ARB, your spring rate would go up to compensate, losing compliance, and also losing grip.

Mike

Tracks like Monaco you need the suspension to be as independent as possible over the bumps and adverse cambers, which would lead you to run very soft or no ARB’s, yet you need the ARB to get the car pointed into the cars into the corner. Somewhere in the middle is the happy compromise.

[Jersey Tom]

Bear in mind also, that if you were to take out your ARBs and replace them with spring (as MReggio states) you're back to where you started from. Steady state load transfer doesn't care if your roll resistance is from spring or bar.

ARBs can increase dynamic load transfer, as on a somewhat supple suspension a single wheel bump input will only lightly transfer load to the chassis and other wheel on the axle. An ARB is a direct mechanical link.

[Callum]

Remember that with load transfer, you have lost more grip on the unloaded tire than you have gained on the loaded tire. Therefore you have lost overall grip.

Why is the a net change in grip if there is no overal change in load? (sorry if it's a stupid question!)

[Conceptual]

Remember that with load transfer, you have lost more grip on the unloaded tire than you have gained on the loaded tire. Therefore you have lost overall grip.

Why is the a net change in grip if there is no overal change in load? (sorry if it's a stupid question!)

Competition Car Suspension
By Allan Staniforth
Description
Suspension design and development is a vital ingredient in the recipe for winning performance. This expanded fourth edition of an easy-to- understand yet in-depth analysis by an acknowledged expert demystifies the complex subject.

Allan Staniforth (author of the well- known Race and Rally Car Source Book) explains the theory and practice of successful suspension engineering in clear and precise terms. He explores how and why suspension systems work and shows how to extract maximum performance. This book, first published in 1988, has been continually updated and has maintained its position as essential reading for drivers and mechanics, whilst providing a fascinating insight for all competition car enthusiasts.

Table of Contents

The reasons why
The springing medium
Location
Ackermann steering angle
The winning package
Active, reactive
The pros — a dying breed?
The amateur at work
Weight transfer
Dampers and monoshocks
The string computer
Setting up
Data logging
Rod ends and spherical bearings
Supporting maths

[MReggio13]

No such thing as a stupid question!!

If you look at a force vs. slip angle diagram for a given tire, there will be a maximum lateral force for the tire at a certain slip angle. This amount is dependent on the vertical force on the tire. If you add vertical force to the tire, your maximum lateral force will go up as well, and if you remove vertical force, your lateral force will go down. Unfortunately, it is not an even trade. Assume you have 300 lbs on each front wheel and during a corner you transfer 100 lbs to the left front wheel, you take it away from the right front wheel. That extra 100 lbs on the left front wheel will increase your lateral force, lets say by 25 lbs, but the unloaded tire will lose its maximum lateral force by 50 lbs, therefore we have lost 25 lbs of lateral force available. Remember, these are not real numbers at all, just an example.

I hope that is somewhat clear.

ARB's are always a compromise, and most high HP cars, especially on street circuits will run without a rear ARB, which will be mainly for applying power over the less than perfect surfaces.

There are many ways to skin the cat, and thankfully for people that like to tune cars, there is no single answer to how to do it, or else we would all do the same thing!

[ICA]

Lets pretend that the circuit our car is on is perfectly smooth with no bumps, to acheive maximum corner speeds we would run the car very very stiff with spring rates and ARB's?

And the reason you would run softer is because of bumps and kurbs?

Regards,

[Jersey Tom]

Wouldn't necessarily be best on super stiff springs. Don't be fooled into thinking stiffening up a suspension quickens or improves the yaw response ("turn in" characteristic) of your car. Yaw response comes from the tires. There is something to be said that spring stiffness will change your kinematic outputs and thus your tire curves, but I'm excluding that as a relatively small indirect effect.

A firm suspension will make the sprung mass react quicker to inertial forces (chassis will take a set quickly, not feel like its lazy and wallowing around), but beyond a certain point you get diminishing returns.

A real fast setup, even on a perfectly smooth track, might involve a relatively soft rear springrate supplemented with some bar. Soft rear springs will let the chassis pitch one way at high speed to shed some downforce and drag by decreasing AoA of some of the aero elements... and pitch the other way to increase downforce and drag under heavy braking.

Just an example. Of course, perfectly smooth tracks don't exist. Nor do perfectly balanced wheels and tires.