It sounds like you're looking at an aftermarket hitch? If so, the only thing that matters is that the hitch is rated for at least what the vehicle itself is rated for. The hitch rating is not telling you how much you can tow or what you max tongue weight is or what your vehicle's payload rating is. That info comes from Subaru, and the payload capacity should be listed on the tire placard on the B-pillar area when you open the driver's door.
Based on what I can find, the 2015 Outback MAX tow rating is either 2,700 or 3,000 pounds, depending on engine/options.
Also based on what I can find, the payload capacity of your Subaru is probably between 1,000 and 1,100 pounds.
Take whatever number is listed on the tire placard for payload capacity and then...
- Subtract YOUR (driver's) weight and the weight of any passengers
- Subtract the weight of any gear, mods, and "stuff" loaded on or inside the car that wasn't there from the factory. So any roof rack and stuff you have on the roof rack, any food, clothing, or camping gear in the back, etc.
The resulting number is your approximate payload capacity remaining. If you have at least 270-300 pounds left then you're roughly in good shape for being able to tow up to the Subaru's max tow rating. I like to use 12% of trailer weight for tongue weight just to be a little more conservative. Say you have 275LB of payload capacity left, with 12% tongue weight that means a max trailer weight of about 2,290LB. I would think a small utility trailer would weigh about 500-600LB, then you've got 615LB for the ATV you mentioned, so that's around 1,215LB and around 145LB tongue weight.
I'd think you should be OK there, but it all depends on how much payload capacity you have left once you do the calculation. The punchline is that the hitch rating doesn't tell you anything about what you can actually tow, it just tells you what the hitch itself is rated for. Actual tongue weight and trailer weight capacities depend on what your Subaru has left over.
