Almost on both counts! Increasing track does decrease weight transfer, while a anti-roll bar increases it. However increasing track primarily decreases weight transfer at the opposite axle and secondarily decreases it at the widened axle. That's why the effect on handling balance is categorically similar to increasing anti-roll bar stiffness on the same axle. Note that anti-roll bar changes have a much more dramatic effect on weight transfer than track width changes, so the effect on handling balance won't be numerically similar even if it's categorically similar.

Adding front track width will move things towards understeer, because it adds more grip at the rear than it adds at the front (net gain in grip for chassis).
Adding front sway bar rate will move things towards understeer, because it removes grip from the front and gives a portion of it back to the rear (net reduction in grip for chassis).

This all assumes everything else being equal, including starting roll rate and grip balance (50F/50R), unlimited suspension travel and static contact patch shape throughout suspension travel and load changes.

Of course those things aren't equal and there are many other factors that have to be considered when tuning a real car. While anti-roll bars increase weight transfer and increased weight transfer reduces grip, if the reduced roll angle results in a more favorable contact patch shape given a car's specific geometry and tire construction, then net grip could actually rise in the end (the benefit to contact patch shape outweighed the negative in weight transfer). Grassroots Motorsports recently had that happen on their ND Miata. Slapping stiffer anti-roll bars on the stock suspension increased skidpad grip because it kept the tires closer to their happy place. But the stock Miata has extreme body roll, and I don't know how the camber curves compare to the S2000, so don't take that to necessarily mean that stiffer anti-roll bars will increase grip on the S2000.

Also of note: Changing front track width in particular effects Ackerman angle and kingpin angle. With spherical bushings the kingpin angle is of little consequence because the geometry will not deflect under load, and the difference in Ackerman doesn't make a huge difference for track-speed steering inputs because the turns are all relatively wide. But I imagine an auto-x car with sticky tires and soft bushings might have some weird stuff happen if you messed with the front track.

 

A wider track decreases the total cars load transfer, assuming you have a sufficiently stiff chassis it is not fair to say that it decreases the axle's load transfer because the axles are coupled. Everything else held constant (sway bars and springs) you are also increase the axle's roll stiffness (roll stiffness is a function of track width and single wheel bump stiffness). Although you will decrease the total load transfer on the car and likely both axles , you will decrease the load transfer more on the OPPOSITE axle. It is definitely counter intuitive..

@thomsbrain The antiroll bar analogy was just to give people an example that they were familiar with, really it all just comes down to LLTD. Very good explanations!

 

I'd fit these:

https://www.s2ki.com/forums/s2000-gallery-12/evasive-motorsports-exclusive-volk-ce28-17x9-5-50-a-1150243/

then play with tyre sizes - 245/265.... And/or possibly a 10" on the rear.

 

Way too expensive for w2w racing unfortunately Jim (unless you want to sponsor me ) as you need 2 sets for a race weekend. Probably over £5K plus tyres.

Thanks for all the replies, I'd missed this in my subscription. Just digesting and will reply shortly.

 

Coming from the man with a top secret bonnet and j's front bumper

 

How does increasing track width on one axle decrease the load transfer more on the other?

 

Doesn't an anti-roll bar simply increase the rate of weight transfer? If anything keeping the body from rolling to the outside of a corner should decrease actual weight transfer. Think about the center of gravity, which is normally above the roll center, shifting outward as the body rolls.

 

Anti-roll bars do increase the rate of weight transfer by increasing the roll natural frequency. Saying they increase load transfer is only partially true, they increase load transfer on the axle at which they are applied but they decrease load transfer on the opposite axle.

Overall ARBshave little effect on the total load transfer, they simply determine the distribution front and rear (along with springs, RCHs CG heights etc.). For reasonable roll stiffnesses, the amount of body roll is unrelated to load transfer, you can double the total roll stiffness and it will not effect the amount of load transfer at steady state.

 

Lots of awesome technical info here guys. Keep it up.

 

....and it all goes right over my roll bar.