It's not the springs, it's simply interpreting the sticker on the B pillar incorrectly as being total payload instead of payload per each tire for that specific application.
My 'tire' sticker states 1218 lbs payload including passengers and loads. So that would be times 4 or 4872 lbs plus the curb weight of the truck which is 5300 lbs for a total of 10172 lbs. My tire Goodyear capacity is 2601 lbs each or 10404 lbs in total.
... Eric
Say what?
Say what? X2. There is a lot more that plays into payload ratings than just tires. Your payload as per the tire sticker is 1218lbs
total, not per tire. If your interpretation was correct then your 1/2 ton truck would have a GVWR of 10k which is 3k over most 1/2 ton trucks!