What should the tongue weight capacity be for this?

[DonTom]

Each bike is 300 lbs, 600 LBs total:


With 300 lbs so far out from the hitch, I wondered how safe this is.

-Don- Reno, NV

 

[CharlesinGA]

I would say no, its not safe. Probably will break off or bend eventually.

If you were using a double receiver hitch like a Torklift, and their super truss extension as the basis for it, then yes, it might work.

Charles

 

[Onyrlef]

Each bike is 300 lbs, 600 LBs total:

View attachment 175126
With 300 lbs so far out from the hitch, I wondered how safe this is.

-Don- Reno, NV

300 lbs is the static weight, ie., it's the weight your rack is supporting while you're parked. The dynamic weight, ie, the weight your hitch is supporting as it's undergoing lateral and vertical, side to side, up and down, bouncing while underway, which is relevant.
For demonstration purposes sit a 16oz. can of pork&beans on your bare foot then drop the same 16 ounce can on your foot from 4' up.
( Given acceleration due to gravity the magnitude of weight is W = mg)

 

[Bearcatrp]

Am assuming it’s a class III receiver. You’re pushing your luck. Either upgrade to a class 4 receiver or put your bikes on a trailer.

 

[tlmgcamp]

OK...time for some math...

Let's assume that the ball is 1 foot to the rear of where the receiver tube is attached to the truck frame. A 600lb hitch weight would put 600 ft-lbs (1 ft x 600lbs) of torque on that connection.

Then assume that the first 300lb bike is 1.5 feet rearward of where the ball would be. That computes to 750 ft-lbs [(1.5+1) x 300)] of torque.

Then assume that the second 300lb bike is 2 feet rearward of the first bike. That computes to 1350 ft-lbs [(2+1.5+1) x 300)] of torque.

That is a total of 2100 ft-lbs of torque on the frame connection. The hitch weight on the ball required to create that same torque is 2100ft-lbs/1 foot, or 2100 pounds.

That number suggests that my assumed distances were very conservative, but you get the idea. Driving down the road you will need to add the additional inertial forces of going over bumps. The rack weight also needs to be acknowledged

I would suggest trailer.

 

[DonTom]

I better mention that the setup is NOT mine. I just saw the thing advertised and it made me wonder about how safe it was.

I am surprised they would even sell something like that.

Not something I would do--at least not for far.

-Don- Verdi, NV (headed for Auburn, CA)

 

[DonTom]

I would say no, its not safe. Probably will break off or bend eventually.

If you were using a double receiver hitch like a Torklift, and their super truss extension as the basis for it, then yes, it might work.

Charles

That looks like it plugs into the hitch receiver, which means it will not help at all for the tongue weight on the hitch receiver.

-Don- Verdi, NV (nice restaurant here as I charge up my electric motorcycle)

 

[CharlesinGA]

That is a dual receiver hitch that Torklift makes largely for the purpose of using this truss. You have to replace the existing hitch receiver and mounting with their Super Hitch to utilize it. Its main use is for trucks with slide in campers overhanging the rear and the owner desiring to pull a boat or utility trailer with motorcycles, etc.

The SuperTruss Extension is available in eight lengths from 21" to 60" and works exclusively with our SUPER HITCH® or SUPER HITCH® Magnum. It's rated to safely tow up to 14,000 lbs and 1,400 lbs tongue weight on a 21" extension and 12,000 lbs and 1,200 lbs tongue weight on a 48" extension.

Lots of good points made above, but as I said before, no, this is not going to work in the long run. Besides the weight bouncing, it will have some twisting effect as I doubt the motorcycles are perfectly balanced on the tube. That will fail, probably sooner than later.

Charles

 

[DonTom]

That is a total of 2100 ft-lbs of torque on the frame connection. The hitch weight on the ball required to create that same torque is 2100ft-lbs/1 foot, or 2100 pounds.

And the Cybertruck with its 11,000 lobs towing capacity only has a tongue weight capacity of 1,100 lbs, or about half that 2100 lbs.

-Don- Verdi, NV

 

[CharlesinGA]

Possibly this video will help with understanding how the hitch and truss is installed and works. This guy has produced good videos and makes extensive use of a GoPro for under the truck, in motion videos.

 

[tlmgcamp]

I better mention that the setup is NOT mine. I just saw the thing advertised and it made me wonder about how safe it was.

I am surprised they would even sell something like that.

Not something I would do--at least not for far.

-Don- Verdi, NV (headed for Auburn, CA)

Items that qualify under "I am surprised they would even sell something like that" could probably fill its own forum

 

[Onyrlef]

Items that qualify under "I am surprised they would even sell something like that" could probably fill its own forum

They keep an inventory of that stuff over at Amazon and WalMart.

 

[tlmgcamp]

They keep an inventory of that stuff over at Amazon and WalMart.

Example...

 

[Domo]

Put one on a front carrier.

 

[Ray-IN]

Put one on a front carrier.

A couple driving an Airstream MH had 2 electric bikes on a front carrier the last time we wintered in Ft. Myers. When I asked, he said they'd traveled perhaps 2,000 miles that way and never had a problem. I excused myself and went back to my MH before my mouth over-ran my brain.

 

[Bearcatrp]

Put one on a front carrier.

Have seen that setup going down the road. It may work but get ready for expensive front end work earlier than needed.

 

[Domo]

Examples - plus, the local transit busses also have carriers in the front for all bikes for the passengers.