Quote:
Originally Posted by Angel And The Wolf
The problem with the lead picture in permalink 51 is that Ackermann steering geometry requires one point in the back to triangulate from, and this photo shows two contact patch centers, putting the Ackermann point in front of one, and behind the other, creating scrubbing and side forces, one to the left, and one to the right. Why not mount the two rear wheels next to each other, side by side. The Ackerman point would then be between the two contact patches, and you would still have four wheels, with little scrubbing (none with freewheels or differential).
|
Ackermann geometry is only close to correct, but at normal cornering speeds, the slip angles on the tires, differentially loaded as they are, produce greater errors and compensate for them all. Good steering geometry is good for handling, but only pushing a car around the shop really shows it at its best. Tandem or even triple rear axles with dual wheels to bear heavy loads on trucks do give a noticeable tendency to run straight, but are easily overcome by two steering wheels and the lever arm of a normal chassis.