Don't know where you got that info, which does not appear to be correct about the class III.
The class I hitch has a towing capacity of up to 2,000 lbs, including the trailer weight.
The Forester has a tow weight limit of 1500lbs (USA), so the Class III hitch is overkill you can't use legally.
Adding a more robust Class II or Class III hitch will give you a larger receiver, but that's it.
Specification of WHAT you can tow on a trailer by class does not exist.
Trailer hitch ratings and vehicle tow ratings are based solely on weight.
I have towed motorcycles myself on a trailer with the class I in both AZ and CA without any issues.
With a lightweight bike trailer, two dirt bike motorcycles should easily fit within the Forester tow limit.
If the dirt bikes are bicycles, there are obviously other options.
You are right @TMX, but two motorcycles will easily exceed the rated FOZ tongue weight, as could just one unless the bikes are little kiddie types.
It is not likely a viable option.
What you want and what you can get are not always congruous...
I have a dual ramp trailer which puts the bikes in line behind the car, and they are a LOT easier to load than the type on the pic. Just drive up and latch down.
Agreed, as stated above, trailer is the best option
Hopefully not too far off topic:
Do Class 1,2 or 3 have differing rated tongue weights for the same vehicle and do they have additional attachment points to support any extra towing weight/tongue weight? Or are the class differentiation literally just down to the size of the square hole for the same vehicle.
So as an example do class 2 and Class 3 have the same towing weights on a forester and it is just down to the hole for the accessories it can handle?
The class of the hitch does not change the tow weight capability, which is based on the vehicle's GVWR, not the hitch used.
If you think about the geometry, a load hanging off the back of the car (like in your picture) is a lever whose force is multiplied by the distance. For a trailer, it doesn't matter, as the tow weight and tongue weight are related.
Hitch weight capability without a trailer is increased, but not up to the rating of the hitch (600lbs), which would make the vehicle dangerous to drive with the wonky weight distribution and exceeding the vehicle's GVWR.
I think that there are 2 measurements for the tongue weight. I think that the hitch can have a higher tongue weight load as available, but it's still the vehicle and chassis that dictates the final weight.
From what I remember, the class ratings have more to do with the overall size and strength of the hitch (regardless of vehicle) and the structure of how it is made. Then the vehicle will have their own trailer class ratings based on engine, chassis, suspension and more.... But the class ratings also increase with the total possible weight rating for the tongue too.
But it is still all finally determined by the base vehicle and any possible upgrades.... Who knows - with heavier duty shocks, struts and springs, maybe the Foz COULD handle more tongue and trailer...
I have (sitting in my driveway) a 1994 Chrysler Town & Country van; purchased brand new the end of 1993... It has the "heavy duty trailer" package. This package uprated the shocks and struts, added an additional cooler under the hood (can't remember if it was oil or trans fluid) and more bits, plus, of course, the class III hitch and wiring that the dealer installed. WIth the package, the T&C was rated at (I think) towing a 5,000 lb trailer. WIthout it? I think it met the class II requirements - is that 3500 lbs?
The Tahoe (or Yukon) in the pic above is a heavy beast and probably starts at class II capabilities, maybe even class III.
@DragonSubie7@FozzieBalou Thanks, I was just wondering why different category of hitches exist. In the UK, you just get 1 type of hitch, called a towbar and the towing capacity is determined by the vehicle, not the hitch. Many brands can make a towbar for the vehicle but they are all the same design and the way it connects to the chassis, the only variations exist are for a removable/hidden/flange type for the hook.
Why would anyone want a lower capacity Class 1 hitch fitted over a class 2 or a higher class? Seems to make little sense. The only thing is perhaps they have accessories for a class 1 with a smaller square hole? But then adaptors exist to fix that problem anyway.
Very Strange way of doing things - Strange that the towbars used in the USA for the Forester have less connecting points to the chassis compared to the UK/Australia etcc.
As far as the ratings for tow load go, a lot of it has to do with the speeds driven in the USA, and the fact that in many overseas markets, additional changes to the vehicle are made, such as thee addition of transmission coolers.
There are lots of threads out there if you search.
Dirt bikes ...as in motorcycles. IMHO, your best bet ...safest, strongest, easiest ...would be a small two-rail bike trailer. These trailers are purpose-built, relatively light and shouldn't be an issue to tow with your Subie. The last thing I would trust toting a dirt bike ....let alone two dirt bikes ...is some kind of hitch receiver carrier.