Your Jeep is also a gasser. I specifically reference diesel issues, which are the ones who typically have overheating issues.
Unless you use the lockers, running a different diameter spare won't cause any problems even in 4wd. The XJ's even came with a donut spare on some trims.
As far as gvwr, nothing. Heavier springs will allow you to carry more weight, and as a non-commercial vehicle you'll never be put on a scale so take that how you want. The tuf springs in my ram advertise a 50% increase in payload capacity, but you likely won't find JL springs marketed that way. Obviously hauling more weight decreases everything from braking performance to handling to acceleration so do what you're comfortable with.
It was more a curiosity. Even if I had my wife and two boys in the Jeep at the same time Id have over 200lbs left. Granted, 850lbs to me sounds ridiculously low. I weight 230 myself and both the boys are still teens. One of them being a good bit taller than I am. I can bet as an adult, especially if he bulks up more, he will weigh as much as I do. Just seems crazy that if all of us were adults you almost cant put anything else in the Jeep.
True, but the op was discussing payload/cargo capacity, not GVWR.
Don't forget about the "fudge" factor. Everything that has been manufactured has a weight limits. But there is always the Fudge factor. If a manufacture tells you that a brand new ladder has a 300 lb weight limit, then it will safely hold 400. If it failed at 301 lbs, then they are risking lawsuits from injured people. Now keep in mind the fudge factor only applies to brand new undamaged things. Once there is wear and tear on something you cannot "trust" the fudge factor or once the product get old and damaged (maybe rust in this case) the original weight restrictions. If they say you can safely tow 3000 lbs, you can probably easily tow 4000 lbs. But the risk of damaging an expensive vehicle by exceeding the listed weight restrictions can be expensive, so exceed the limits at your own risk.
Anyone with LSD , a common option, would be in trouble, alas. The tires could be swapped , so the axle ends matched, and the mini spare used on the front. Any LSD I had, always came with a matching spare, even in a Renegade, Trail Hawk .
GVWR is stupid low on a lot of vehicles it seems these days. My 2017 ram rebel only leaves like 970lb capacity if I recall correctly. Put 5 large adults in there and it's over weight in a pickup with an empty bed! And the thing is rated to tow 11k lbs so if you're arguing it is brake/engine/cooling system/ or even frame strength limited something doesn't add up. While it still had the air suspension I hauled a 2500lb pallet of bird seed 200 miles up into the mountains with 500+lbs of passengers. Sat level, handled fine, acceleration was good, braking was fine. 80k+ miles later and it clearly didn't damage anything. Now it's got tuf springs that advertise 50% payload increase and I'd have no issue throwing 1500+lbs in it at any time.
Completely incorrect.
