Probably 2500lb axles most carry on tandems, you can get close to 5000lbs on it if made right, sure those are.
The tandem will add about a extra 600-850lbs with extra axle.
2014 JD 920M 7-Iron Pro 48" 23.5 hp Kawi
Echo - 210, 225
5x10 (upgrading winter)
All truth passes through three stages. First, it is ridiculed. Second, it is violently opposed. Third, it is accepted as being self-evident.
Arthur Schopenhauer, (1788 – 1860)