On Sun, 2010-03-07 at 08:45 +0800, Ed Greshko wrote: > Les wrote: > > > > Do you know that the car has a differential or what that does? The car > > would not work without it, but it is not part of the knowledge you need > > to drive the car. But you do need to realize that the wheels rotate one > > way on one side and the opposite on the other and that they run at > > slightly different speeds, if you are going to race. That small bit of > > knowledge along with other similar bits would make you the exception on > > the course and give you an advantage. It is the same with computers. > > > > > I hate to mention this...but I wouldn't want to have you as my > mechanic. :-) > > The wheels of a car *do not* rotate one way on one side and the opposite > on the other. You have simply changed your frame of reference. Roll a > bicycle forward. Standing on one side of the bike, the wheels are > rotating clockwise. Stand on the other, they are rotating counterclockwise. > > A car would work without a differential in much the same way a wagon or > cart would. However, when cornering the tires would need to rotate at > different speeds. This would tend to cause slipping on one side and > dragging on the other and lead to control problems as well as damage to > the tires. > You are both right and missing the point. If you take the wheel off one side of a car and put it on the other, its direction of rotation changes, because it is mounted to a rim that will only go on with same side against the hub. Thus I can say that the wheels do indeed rotate one way on one side and the opposite on the other. You said it yourself, clockwise on one side and counter clockwise on the other. It is an engineering function. And it is not just cornering where the wheels rotate at different speeds, but all the time. Tires wear, so even if they started out measured to microscopic tolerance, over time they would be different diameters. This means the wheels rotate at different speeds even going down a straight road. Cart wheels actually rotated independently of the axel for this very reason. Look at the old wagons, or even roman chariots, the axel is a bar, but each wheel rotates on a bearing on that axel. Some basic vehicles use a solid axel and just put up with the stress on the axel and wear of the wheels, but most alleviate it in some way. And I would not want to be your mechanic. Regards, Les H -- users mailing list users@xxxxxxxxxxxxxxxxxxxxxxx To unsubscribe or change subscription options: https://admin.fedoraproject.org/mailman/listinfo/users Guidelines: http://fedoraproject.org/wiki/Mailing_list_guidelines
