Un - sprung weight

What is it?
How would one know if it exists?
My XJ is fitted out with OEM JK Moab wheels and tires along with dual piston calipers and 13 inch rotors. I know the brake hardware are significantly heavier the the OEM units. Would these affect the Un - sprung weight?

Sprung weight is anything "above" the springs.
Unsprung weight is anything "below" the springs.

Unsprung weight includes the axles, tires, brakes, etc. So yes, heavier wheels and tires do affect the unsprung weight.

you have more unsprung weight than you need. at least in a perfect world. Unsprung weight is everything below the springs and about 1/2 the weight of the springs. so, wheels, tires, steering (1/2 the drag link) axle, gears and 1/2 the drive shaft is all unsprung. What is bad? when you hit a bump the mass of the unsprung weight takes a lot of time to get out of the way of bumps and that slows down the ability of the suspension to respond resulting in a great speed loss over bumps and more chassis path disrution. What is good? I have no idea. may be better traction or something. I go pretty slow over bumps so I am not outrunning the reaction time of my unsprung weight which with one ton axles is around 25% of the vehicle weight. If I was racing offroad I would spend a big part of my budget reducing unsprung weight in an effort to increase the speed in which the unspriung weight is able to respond and recover from a bump. for speed its a huge issue, for crawling it may be advantageous.

I would say rock crawling might be the only powersport where unsprung weight is not a disadvantage. Makes the vehicle more stable on tippy stuff.

https://www.amazon.com/Chassis-Engi...473205161&sr=1-1&keywords=chassis+engineering

ALL you ever wanted to know (not really), and then some!

I think it depends on how you wheel. If your just running backcountry or woods riding then it really doesn't do anything other than make your rig heavier and help in off-camber situations. Picture lying a Dana 44 on a bank at a 45 degree angle, now pick up the upper side and lift it. Now picture using a Dana 60 instead, it's impossible to lift one side even on a steep angle. However if Climbing and Rock Crawling is you thing then it's weight and no matter how you dress it up the heavier your rig is the harder it is to drag it up a ledge.