I read somewhere that in longer races, where you have 100% fuel, it is a good idea to change the ARB settings as you use up your fuel and your car becomes lighter, but unfortunately I dont remember the part about how you should change the ARB, stiffer or softer?

I am more specifically looking for tips on a BF1 car with 100% fuel. Thx

So basically with 100% fuel, you should soften the anti roll bar at the start of the race, and then slowly stiffen it until it is as stiff as you would have it during qualifying etc.

I might be wrong here but I thought that stiffening the rear would make it even more tailhappy. I think you'd have to stiffen the front or lower the rear...

Quote from imprezzer :

I might be wrong here but I thought that stiffening the rear would make it even more tailhappy. I think you'd have to stiffen the front or lower the rear...

Bingo.

welcome to the delights of a proper sim m8

any race car setup is a compramise between the differing needs of the car as its condition changes, this is one reason why you used to get more interesting races in f1 before refueling as the team / driver has to make choices between being set perfectly when heaviest with new tyres, lightest with worn tyres or do you go for a compramise.

how you set the car up to start with is your choice and can only come from trial and error and prctice, you can then use the antiroll bars and the brake balance to alter this setup whilst racing.

as mentioned above basically a soft roll bar gives more grip to the end of the car its fitted to BUT a soft roll bar will cause more body roll which can actually cause less grip due to inertia. best example to try that everyone will be familiar with is use a closed top racer at blackwood and try the chicane with antiroll fully soft, you can feel the roll draging the car.

brake balance can be altered to compensate for changing weight distribution, which is more of a problem in closed top cars than single seaters which are usually designed to have their fuel stored as near as possible to center of gravity to reduce this effect.

also as tyres wear the balance of grip will change so you can use your roll bars and brake balance to compensate for this, for most lfs racers i'd thik that given the average race length the only effect they'll have to worry about is tyre wear, especially for drivers / cars that cook their tyres at one end more than the other.

all of the above is one of the reason's why the fastest setup isn't always the best setup for racing, another is driver fatigue which once again can be compensated for by "live" changes i.e. making the car a bit more forgiving as your concentration fades.

Recycling this thread here. I've read here:

http://en.wikipedia.org/wiki/Anti-roll_bar

that stiffer ARBs increase weight transfer. But I've been taught that weight transfer is a function of Centripetal acceleration, car weight, c.g height and track width. Confused here

Overall load transfer has nothing to do with ARBs.

But the roll stiffness distribution can vary. So for a given total load transfer, the arbs (and springs and geometry and other things) define how much of that total each end transfers. So a stuff bar at the rear would mean the rear transfers more of the total than the front, which causes more oversteer due to tyre load sensitivity.

Quote from GenesisX :

Recycling this thread here. I've read here:

http://en.wikipedia.org/wiki/Anti-roll_bar

that stiffer ARBs increase weight transfer. But I've been taught that weight transfer is a function of Centripetal acceleration, car weight, c.g height and track width. Confused here

The total weight transfer equation is always true irrespective of suspension design and damping. Stiffer roll bars increase the lateral load split (i.e the difference between the force applied to the outside and inside wheels)

For an example, if you put a stiffer rear anti roll bar on, the calculated effects for a right hand turn using just sprung and unsprung mass calculations would be:

• LF load decrease
  
• RF load increase
  
• LR load increase
  
• RR load decrease
  

Your overall load transfer from mah/T would be the same, but a larger percentage of that load is applied to the left rear tyre along with the rear transferring more total load than the front. (due to the load split decrease on the front and increase on the rear).

if you wanna make setup right..first you need right springs, after that you compromise with ATR and little bit od bump, rebump and front rear hight of car.
that is pure basic ..

first make pure basic right , after that, all is fine tunning that make it all work oor, good,nice, gre8, perfect
if you made setup in the right way there isent need to correcnt setup during race. one can do it all..
if it doesent ,go back to basic..
im in lfs since beagining and in setups making long time..and after more than 5 yeras of lfs setup testing/making and rl car full setups making i lerand my basic.. so you can bealive me on what i say.


P.s

Once you read thousands of books on engineering the suspension, check it all in real car on the road and track, going full throttle , then you start fully appreciate the LFS
so,
2 p.s thanks you Scawen Roberts, Eric Bailey, and Victor van Vlaardingen

You made LFS better than you think it is
true fun since beginning
sry for my bad eng.;(

Thank you all for the responses. I'm starting to understand this better. So ARBs would affect how much weight transfer is being "reacted" by each axle. But this is kind of where it gets a little counter-intuitive for me. A stiffer ARB leads to more weight transfer at that axle.

Taking a right hand corner as an example, the right side suspensions get depressed, causing the right end of the torsion bars upwards. A very stiff ARB would mean that the left torsion bar is deflected upwards as well, reducing roll and forcing the left wheel to be placed on the ground. - Or - does the chassis continue to roll and the ARB actually tucks the inside wheel into the chassis, pulling it away from the ground?

Also, F:R weight distribution doesn't change even though through changing ARB settings, each axle reacts with different weight transfer loads?

If your car was just one axle, then the ARB/springs can't press the tyre onto the ground as such. The left side is pulled upwards by the right side, and the car will load both tyres by the amount of load remaining after the weight transfer (elastic and geometric).

But if the other end of the car has an axle as well (most do!), then it's a bit more complex. If the rear is very soft in roll, then the front roll bar will pull up the left wheel, and the car will roll less for a given lateral g, but have more load transfer at that end, to the point that it might run out of droop travel, and hence reach 100% load transfer when the tyre leaves the road.

Springs do not press tyres into the road. Neither do tyre pressures. The only thing that presses down is the load (weight) of that corner, and that load varies with acceleration. A stiffer spring or bar at that corner will change the dynamic load due to changes in load transfer, but the static corner load might stay the same.