Some inputs - The reason for the increase in front ride height when MMC moved from SUPLEX to SPAX is that the SUPLEX units had a clever elastomeric 'spring assist' on the damper rod (like a very posh long durable closed cell foam bump stop) that came into contact quite soon in bump to give a rising rate (nice!), but when SPAX got the business they did not use a rising rate so increased the ride height instead to minimise full bump impacts. This is compounded as the geometry itself actually gives a falling rate which is bad.
Thus the SUPLEX units actually have less travel in bump than the SPAX but then contol it better. The less bump travel of the SUPLEX units also minimised the amount of bump steer, hence with the SUPLEX units there is no noticeable bump steer (well I did not notice any). From what I see, the wheels toe-in with bump, but I do not know the full relationship of suspension travel with steer. Obviously it can be designed out with correct rack height and track rod length or minimised with bump travel control as originally. Also if the direction of bump steer with travel is consistent then it is easy to cope with compared with bump steer that goes from toe-out to toe-in or significantly increases in bump.
The SPAX units also have lots of rebound travel, whereas the SUPLEX units have an internal spring in the unique damper that is effectively a rebound spring so minimising rebound travel and thus significantly increasing roll stiffness.
The SPAX units try to control rebound with excessive rebound damping which is maybe OK for a single excursion into a pothole or a single change of direction, but can causes 'jacking down' of the vehicle over a series of inputs. This is when the wheel can not rebound fully before the next bump, hence the wheel gets jacked up over a series of bumps, such as the bumpy kerbs on the inside of a race track until the suspension is on full bump waiting for the next bump - with no more suspension travel - ah -wonder what happens then?
I hope this helps. SUPLEX upgrades available soon I hear ;-)
I've forgoten what the question was now........
Best regards PJB.
