Chucking

Bowti wrote:

Garyl53 wrote:
I have often wondered if the rear axle movement (wrap or just back/forth movement in response to trailer forces) contributes significantly to the chucking. The one thing that I can't easily explain is the frequency of the back/forth "chucking" feeling on driver and passenger appears to be much faster than I would think a trailer hitting road imperfections could generate. Considering it happens as much or sometimes more on smooth roadways is puzzling to me.

Gary, this is the action that I am thinking of. For those who think you are just cruising along with no axle wrap remember your fuel mileage most likely went from 18 or 20 MPG empty to 8 or 10 MPG pulling that 16K trailer. Your engine is working and pulling big time. If you get that 16K lbs pushing and then pulling on your truck something is going to move. It might just be axle twisting against the leaf springs.

Understand that I am not saying this is the cause of all chucking but it might be something that is being overlooked in the search for a cure.

I never thought about the axle twisting. Maybe give some traction bars a try.

Garyl53 wrote:
I have often wondered if the rear axle movement (wrap or just back/forth movement in response to trailer forces) contributes significantly to the chucking. The one thing that I can't easily explain is the frequency of the back/forth "chucking" feeling on driver and passenger appears to be much faster than I would think a trailer hitting road imperfections could generate. Considering it happens as much or sometimes more on smooth roadways is puzzling to me.

Gary, this is the action that I am thinking of. For those who think you are just cruising along with no axle wrap remember your fuel mileage most likely went from 18 or 20 MPG empty to 8 or 10 MPG pulling that 16K trailer. Your engine is working and pulling big time. If you get that 16K lbs pushing and then pulling on your truck something is going to move. It might just be axle twisting against the leaf springs.

Understand that I am not saying this is the cause of all chucking but it might be something that is being overlooked in the search for a cure.

Does it hurt anything? Not really, so I just ignore it. I learned this lesson from hauling tube trailers with partial loads. They had a lively ride, both up and down, and the banging as the fluids rocked from back to front. Anti slosh plates, my tail section.

Wild Card wrote:
The problem is the inherited bad design of towable rv. Wheels more in the center acts like a see-saw. The end result is what is being called chucking. Some are lucky to get suspension stiff enough to compensate, some use air bag hitch and heavy pin. Rv is the only thing I have pulled that causes this problem

Wild Card has it right,
Wheels in the center are the culprit, If they were in the rear like tractor trailers there would be no issues.
The only this we can do is add a lot of weight to the king pin or buy a TS3 hitch.
I went with the TS3 hitch

I have often wondered if the rear axle movement (wrap or just back/forth movement in response to trailer forces) contributes significantly to the chucking. The one thing that I can't easily explain is the frequency of the back/forth "chucking" feeling on driver and passenger appears to be much faster than I would think a trailer hitting road imperfections could generate. Considering it happens as much or sometimes more on smooth roadways is puzzling to me.

In my experience, porpoising, up and down movement, is usually caused by too light a pin or hitch. You can have it with both bumper pulls, FWs and GNs, and I've experienced it with all 3.

Lyle

Wild Card wrote:

RinconVTR wrote:

goducks10 wrote:

jerem0621 wrote:
Is Chucking a Fifth Wheel only issue?

I have never experienced anything towing my TT that is reported by fiver owners.

Thanks!

Jeremiah

I guess the call it porpusing on a TT. .

Chucking is really only 5th wheels/Goosenecks.

Porpoising is very different...more up/down vs push/pull.

Same problem. Just one is coupled 4t behind axel an 1 is coupled at the axel, resulting in a different feel.

Naw man...this is an age old 5th wheel effect discussed a million times. NOT the same as porpoising.

Proper use of terms is very important.





porpoising;
move through the water like a porpoise, alternately rising above it and submerging

jerem0621 wrote:
Is Chucking a Fifth Wheel only issue?

I have never experienced anything towing my TT that is reported by fiver owners.

Thanks!

Jeremiah

Yes. Both travel trailers and fifth wheels create forces due to road imperfections. Due to the high hitch angle on a fifth wheel the forces transferred to a 5er hitch are a combination of bouncing forces and chucking forces (fore and aft). Since a bumper hitch is the same height as the axles the hitch angle is zero and all the forces are up and down.

RinconVTR wrote:

goducks10 wrote:

jerem0621 wrote:
Is Chucking a Fifth Wheel only issue?

I have never experienced anything towing my TT that is reported by fiver owners.

Thanks!

Jeremiah

I guess the call it porpusing on a TT. .

Chucking is really only 5th wheels/Goosenecks.

Porpoising is very different...more up/down vs push/pull.

Same problem. Just one is coupled 4t behind axel an 1 is coupled at the axel, resulting in a different feel.

goducks10 wrote:

jerem0621 wrote:
Is Chucking a Fifth Wheel only issue?

I have never experienced anything towing my TT that is reported by fiver owners.

Thanks!

Jeremiah

I guess the call it porpusing on a TT. .

Chucking is really only 5th wheels/Goosenecks.

Porpoising is very different...more up/down vs push/pull.