Interesting. I hope we're able to upgrade (for a modest sum) the first gen Grenadiers with the tweaks to increase payload.
I have no doubt. Likely just needs +500lbs springs in the rear and perhaps higher load range tires, I haven’t checked where the 17” rim diameter BFGs top out. The frame is likely already engineered for such payload.
When I had my 3/4 ton GMC the only manufacturing difference between it and the 1 ton was that it had 2 additional overload leaf springs in the rear and higher load range tires that was it. It was I believe $375.00 MSRP difference to get the overload leafs and higher GVWR door sticker. This was the difference between a 10,000lb and 10,500lb GVWR and 1,500lbs of payload vs 2,000lbs. The reason GMC had the 10k version was for tax purposes in the US - the vehicle is classified differently after 10,000lbs in some states I believe.
The +500lb springs for the grenadier already exist. There is at least one forum member who has also added air springs to the rear of their grenny.
That being said you cannot legally change the payload rating of a vehicle at least here in North America. That does not prevent owners from modifying their vehicles, but it will never be certified and legal, technically speaking, if you overload the vehicle beyond its door sticker.
For my GMC it was my tow vehicle and I added supplemental air springs in the rear rather than another leaf and upgraded tires (to BFGs which had higher load range). I ran the vehicle when towing at around 250lbs over the door sticker GVWR. It never bothered me because I knew the vehicle was designed for it from the factory, minus the 2 elements I mentioned above. I preferred supplemental air springs because I could essentially not activate them when I wasn’t towing / had max payload, so the ride was better. I’d also adjust tire pressures based on my actual weights, vs just maxing out tire pressure per the door sticker which tells you to air up to support max GVWR, which gives an unnecessarily harsher ride when not loaded.
Weight scales (like CAT scales in the US) are your friend. Everyone should know where their loaded vehicle rests from a GVW perspective. I regularly weighed in as I changed things or adjusted trailer loads.
