I don't think that's correct. One of the assumptions in that spreadsheet is that the weight transfer at the rear is ALL from roll center height and is independent of CG height. Remember my discussions with Robert about this? One effect of a true zero roll rear suspension is to unlink the weight transfer at the rear from the CG height and thus it's effect on weight transfer. It still depends on CG location fore and aft, just not height. Look at the "Rear WT due to RC Height (lb)" calculations in the spreadsheet. These are significant numbers.hardingfv32-1 wrote:From your weight transfer spreadsheet, the total weight transfer number for a 1" CG change is about 12 lb. I assume that includes the change in the roll center. If so, I estimate about 3-4 lb of weight transfer change per degree of rear camber.
I believe we do.hardingfv32-1 wrote: I think a normal 100 lb rear wheel system is giving up about 25 lb per deg of rebound. Do we have the numbers to send the system into a over center condition?
My point is that the combined "spring rate" of a soft spring pushing into a soft (but non-linear and getting stiffer fast) cushion is a the same as a stiffer spring before it hits a hard limiter: the lift force from the spring falls off fast as the car rises into the cushion just like a stiff springs lift force will fall off faster than a softer spring (before either hits a limiter of any kind).hardingfv32-1 wrote:2) Ignoring the possible requirement for a soft land for the droop limiter, what is the benefit of stiffening the spring system as the droop limiter is engaged?
Brian
An advantage of the soft cushion would seem to be that you could run a softer (more compliance) spring but still reduce the spring's impact on jacking BEFORE you actually hit the droop "limit" (where by definition the spring force = the cushion force).
The disadvantage would be that the droop "limit" is less defined, and over bumps and rises, the inertial effect of the car's motion could over-compress the cushion leading to more positive camber than is desirable and thus a possible temporary loss of traction greater than the unavoidable loss just due to the effect of the CG wanting to move away from the track surface in the first place. Of course this is where the "slow" setting of the shock comes into play. Too stiff and the suspension can't follow the pavement at all, too soft and it hits the limiter too hard and overtravels causing loss of camber, leading to loss of traction. Probably oversimplified and incorrect...