Raising the RC will increase the amount of load transfer that is carried through the suspension links, therefore increasing the percentage of total lateral load transfer carried at that end.
Unfortunately every vehicle dynamics book I have seen gives an explanation of RC that is incorrect to...
I think Greg is saying...the solution(s) to your problem is dependent on the specific design of your vehicle and operating conditions.
I will say that reducing the front RC will reduce steady-state Understeer, but may make your turn-in problem worse...
Two reasons come to mind.
1. May be packaging to allow a longer rear toe-control arm to reduce rear toe-link loads & result in less toe deflection during cornering
2. Or the opposite reason may be a deliberate desire to induce toe deflection during cornering by increasing rear kingpin moments...
To back up Greg,
-the moment of inertia about the "roll axis" is NOT a quantity of interest.
-Raising the "Force-based" roll center reduces the roll moment on the sprung mass for a given lateral acceleration this is why the roll gradient is reduced....I would expect little change in the...
I have seen data for tires where there is a "lower limit". In particular heavy-duty truck tires and a certain "over-tired" high-end American muscle car. In the snow/dirt I believe there is a lower limit as traction is very dependent on the ability of the tread to "dig" into the surface.
Often this difference can be attributed to two things:
1. Styling thinks the car will look better with a wider rear track
2. Suspension geometry or tire size changes in the front or rear suspension for packaging, performance, etc. later in design cycle(or if the vehicle is an iteration of a...
I'll have to agree with Greg here....The chassis does not roll about the Roll axis. MBD simulations quickly dispell this myth. A few good SAE papers have also be written on this topic.
The MOI of the sprung mass about the axis connecting the front and rear RC would only be relevant if the...
Be carefull about reading up on Roll Centers and "mass centroids" in Milliken. My recollection is that the description given in RCVD is in error! The only correct discussion of RC's I have seen in print are in SAE papers and Mark Ortiz's articles in Racecar Engineering.
There is no such thing as a mass centroidal axis. What Carroll Smith was trying to describe is the principal axis for vehicle roll inertia - this is the reference axis that minimizes roll inertia. The concept that Carroll Smith describes in "Tune to Win" is incorrect in several respects:
1...
"OK, so here's the experiment. If I multiply all the compliances in the system, and the tyre cornering stiffness, by a factor of 4 then I should reduce the delay time by half."
I don't think this experiment would hold true. A vehicle's dynamic behavior can be simplified as classical 2nd order...
Shanba is correct, lateral acceleration can not occur until the vehicle has begun to assume a sideslip angle which creates rear tire slip angles and resultant force. One of the key motivations for active rear wheel steer is reducing the phase lag between yaw yelocity and lateral acceleration...
I agree with Greg that the key issue is a rack ahead of wheel center promotes deflection understeer and rack behind wheel center will tend to have deflection oversteer. I would add that a rack behind wheel center does have two advantages 1)often allows a tighter vehicle turn radius by allowing...