Sprung weight vs unsprung weight.

inkjunkie said
This was my next question.
I remember reading about this in a chassis book a long time ago.
Next part of this question...is unsprung weight seen the same as sprung weight? Perhaps that is not the best way to put it. In the book I was reading the author was emphasizing how losing 10 pounds of unsprung weight is the equivalent of losing 100 pounds of sprung weight performance wise. Didn't make much sense to me back then...still doesn't now. Might have actually seen it in a wheel catalog...or perhaps it was an old Wilwood catalog. Sounded like a bit of a sales pitch but...
Anybody know if this is actually factual or just some sort of claim to try and get folks to spend their hard earned $$ on a certain brand of products?

yes and no. this is where is gets complicated. Unsprung weight and sprung weight, while independent of each other, can, in certain aspects, affect each other. For drag racing,most of the unsprung weight isnt a huge deal. For road racing, unsprung weight because very important. not only from a spring selection but for shock selection and adjustment as well as wheel control, suspension travel, roll center and center of gravity. That being said, unsprung weight changes can alter a cars performance just as sprung weight can. However, there is NO 1:10 rule or 1:5 or anything. Unsprung weight changes will not affect a car's acceleration or top speed any different or at any different ratio than sprung weight changes.