Tow package vs accessory hitch option

[rainforest]

Yes, so you see, when towing a trailer, the weight can be higher. With just an accessory for bikes, the tongue weight I believe is only 120lbs. That is way too little to carry 4 bikes, but there doesn't seem to be another option.

 

[beths11]

@ohmman would you comment here? If a person has the full tow package what is the limit that the hitch can handle in the form of a cargo box and contents?

 

[ohmman]

The tongue weight with the towing package is 500lbs. I would assume that a cargo box that exerts a similar downward pressure would be fine. Remember that you'd measure that at the tongue, so the further you cantilever outward, the lower the rated weight. It would be easy enough to calculate with a little geometry.

 

[goneskiian]

I don't know if I can answer this well enough but I will try. The weight rating for tongue weight is different from the accessory because in the case of the tongue weight, it is from a trailer being connected. the weight on the hitch can vary depending how the trailer is loaded. If more weight is toward the front of the trailer, there is more weight on the hitch. But in all conditions, the weight on the hitch is always mainly straight down. Because weight is distributed between the hitch and the wheels of the trailer.

In the case of an accessory being connected to the hitch, all the weight from the accessory is being supported by the hitch, so you have a weight on the hitch that is cantilevered (hung) from it. The hitch is not only resisting downward weight, but also torque. The accessory hanging from the hitch is trying to bend it (twist it) downward. It is this torque that has to be accounted for and therefore reduces how much weight the hitch can take versus a trailer where the hitch only needs to oppose a downward force with little torque.

If we have any mechanical engineers, or perhaps structural engineers in the audience, they can explain it better than me. But there is a physical reason why the rating for an accessory load is lower than the rating for a trailer load (tongue weight). It's the same hitch is both cases, but it is being loaded differently.

I just thought of an analogy that might help visualize what I was talking about. Take a flag pole and you hold the base of it up while someone else is holding up the tip. You feel half the weight of the pole on your hand. Now take that pole and cut it in half. Now you again hold your half of the pole by its base but no one else is holding the cut end. You're still holding the same amount of weight as before, but now you're having to deal with more effort in order to keep it level because it's trying to hang down on the other end. It's this additional effort the hitch has to deal with that reduces the amount of total weight it can take.

You're overthinking this. The Accessory Hitch (originally Specified as a 1.25" receiver) doesn't exist. Ignore the 120lbs and go with the tongue weight of the tow package (with a 2" receiver).

I have a 4 bicycle rack rated to carry bikes up to 50 lbs per slot. That's 200 lbs. The rack itself weighs 82 lbs. I would not hesitate to carry this much on the provided tow hitch receiver with a tongue weight rating of 350 - 500 lbs.

 

[Jrogville]

You're overthinking this. The Accessory Hitch (originally Specified as a 1.25" receiver) doesn't exist. Ignore the 120lbs and go with the tongue weight of the tow package (with a 2" receiver).

I have a 4 bicycle rack rated to carry bikes up to 50 lbs per slot. That's 200 lbs. The rack itself weighs 82 lbs. I would not hesitate to carry this much on the provided tow hitch receiver with a tongue weight rating of 350 - 500 lbs.

I wasn't talking about the nonexistent Accessory Hitch. What I was arguing was that the allowable load for an accessory rack should be different from the allowable tongue weight from a trailer. I still think that a load hanging from the trailer hitch will create more stress on the hitch than a simple load down from a trailer. The hitch has to deal with torque from the cantilevered load as well as the simple weight.

But for a counterpoint, I was just looking at the StowAway2.com web site which sells a carrier box you connect to the hitch. They say that the calculation to determine if your hitch can handle their carrier is to take the tongue weight and subtract the weight of the carrier and the weight of your gear. They're not figuring in any adjustment for the torque involved. StowAway is a great product that I own and trust, so I'm not inclined to argue against them.

 

[goneskiian]

I wasn't talking about the nonexistent Accessory Hitch. What I was arguing was that the allowable load for an accessory rack should be different from the allowable tongue weight from a trailer. I still think that a load hanging from the trailer hitch will create more stress on the hitch than a simple load down from a trailer. The hitch has to deal with torque from the cantilevered load as well as the simple weight.

But for a counterpoint, I was just looking at the StowAway2.com web site which sells a carrier box you connect to the hitch. They say that the calculation to determine if your hitch can handle their carrier is to take the tongue weight and subtract the weight of the carrier and the weight of your gear. They're not figuring in any adjustment for the torque involved. StowAway is a great product that I own and trust, so I'm not inclined to argue against them.

Good points for sure and I most definitely appreciated following your train of thought on this issue. My apologies for minimizing it and I may have lost sight of the flow of the thread changing to talking about cargo boxes. I don't think anyone hauling bikes will be able to load it up that heavy anyway unless they throw 4 Ebikes on there. A cargo box may push that though.

Cheers!

 

[ohmman]

I wasn't talking about the nonexistent Accessory Hitch. What I was arguing was that the allowable load for an accessory rack should be different from the allowable tongue weight from a trailer. I still think that a load hanging from the trailer hitch will create more stress on the hitch than a simple load down from a trailer. The hitch has to deal with torque from the cantilevered load as well as the simple weight.

But for a counterpoint, I was just looking at the StowAway2.com web site which sells a carrier box you connect to the hitch. They say that the calculation to determine if your hitch can handle their carrier is to take the tongue weight and subtract the weight of the carrier and the weight of your gear. They're not figuring in any adjustment for the torque involved. StowAway is a great product that I own and trust, so I'm not inclined to argue against them.

To support what Stowaway has said, my trailer also is cantilevered out from the receiver. The hitch ball isn't flush with the rear of the car; it's pushed outward quite a ways. I'm working to minimize that gap, but this is the norm. So I think you'll be fine with up to 500 lbs minus the weight of the carrier.

I'll be curious to know whether the car senses the load and puts it in "tow mode" at that weight, though. If it does, Autosteer will be disabled.