Technical Question on trailering

I wonder if you guys ever played with the 2 balls stacked and dropped experiment.
You place one ball ontop of another and sorta balance it, then drop them both. What happens is the ball on top shoots off of the bounce with exponential energy.

 

Sounds like a good way to get out of warranty for some ****ty made shocks

 

I've towed everything from small cars to lifted 4x4's on open trailers all tied down by the axles never by the ch***is, and I've never had a issue. Most poor pulling loads have to do with how it's loaded, a few inches to far forward or rearward has a drastic effect on how it tows.

 

I've always strapped the frame rails, but when I bought a new car hauler trailer a while back it had axle straps in the toolbox so I used them, and didn't notice much of a difference. No matter what I always use an industrial lifting sling as a safety strap tied loosely to the car and the trailer, just as a backup.

On another note, earlier today I dragged my '61 Ranchero backwards on the tow dolly from my house to the storage unit. I had already worn myself out trying to load the car on the dolly in an awkwardly steep L-shaped driveway and didn't feel like flipping it around to tow it properly once I got it down to the flat street. I did strap the steering wheel so it couldn't move. Fortunately for me and my little 4 cyl truck it was only 1.5 miles of twisty hills, but it was sketchy as hell and I do not recommend loading a car backwards on a tow dolly.

 

when we pulled them on the transport racks its by the ch***is and tight ( compress the suspension ) and they prefer straight down because the ways the racks are made ( criss cross is allowed if the hook points are outside the vehicle frame area ) , as you do not want it to start a pendulum effect as the car can start rocking back and forth or side to side on the suspension and cause a bad swaying effect on the trailer deck and rated straps should be inspected for fraying and no folding or looping over when you use them , but straps are not the proper hauling method they ( DOT ) says you should use chains 5/16 grade 70 proof tagged , as commercial carriers we had to use them, not straps and if straps are used they have to be US DOT and Cal DOt Rated straps ( the tag must be on the strap ) and they are 3" and 4" wide , most people use straps as you do not have to buy the propper binders to tighten them down . and chains last longer . also if you use straps use a safety chain in case on should fail and might cause the vehicle to try to roll off the trailer .

 

on auto racks we can adjust the height of the rack for the vehicle above and often there is plenty of room above the vehicle to walk under the rack ( except if you double stack pickups or have vans on the top which often means we have nothing in the lower or economy cars ) as for frame pull out never happens , the t slot or j hook is made to prevent this its not a standard hook end

 

In the case of a vehicle on a common tandem axle flat deck 18' car trailer, the large ball (item with greater m***) is the load and the small ball represents the trailer's lesser m***. So, if applied to the issue being discussed, it seems to me to be upside down and would have the opposite effect to what I think you are implying.

My reasoning suggests the real life effect would be the load (large ball) would dampen the rebound of the trailer (small ball). It seems to me that the in the case of vehicle and trailer, the vehicle tied to the top of the trailer becomes part of the trailer's "sprung weight" , no matter how it's tied down, but possibly even more so if tied down with the vehicle springs compressed to eliminate any rebound of the vehicle.

The example of the two balls cites their velocities (V) , both actual and relative. For example after the first ball (big one) has rebounded (right side of illustration 2), the small ball has 2V shown next to it. As the text indicates, the observer "sees" 2 V, but that is the closure rate (relative speed) of the two balls, not an increase in the small ball's speed, because the large ball has reversed direction during it's bounce and is now traveling upward at V. (Not actually at the original V, because some energy has been dissipated in the bounce, but close enough for this purpose). But it is the relative m*** of the larger ball that imparts additional energy (3V)to the small ball when they collide.....as mentioned in the text.

This illustration could be used, with slight modification, to show what happens when two vehicles of different m*** collide in a head on impact. An average car and a large truck, for example. Two vehicles, one large and one small, each traveling at 60 mph, but in opposite directions, collide. The stored energy of the larger vehicle not only stops the smaller vehicle, but reverses it's direction of travel.

All that said, it's an interesting example of physics, but I'm failing to see much applicability to the original subject.

Ray

 

Every car is different - even a**** same model years & makes.

Every trailer is different.

Whatever you feel comfortable with for your vehicle - that is all that matters.

In general - a (4) point tie down to the corners is best using ratcheting straps
w/ spring loaded hooks attached to nylon axle straps.

I winch all vehicles on & off my trailer - I leave the winch line attached
for the trip & disconnect the wireless remote at the winch control box
so a false signal does not activate the winch in transit.

My enclosed car hauler trailers all have e-trac installed,
on average about 60 feet a trailer that is bolted thru the floor.

Where you fasten depends on the axle - frame configuration.

For example - I just dropped off this 1972 Charger Survivor in Ohio
yesterday - I fastened the rear tie downs to the leaf springs & crossed
the straps to minimize side movement of the car.

The rear brake line routing on the axle prevented fastening at that point.

Because this is a wide body car in an enclosed trailer - you don't want
it shifting suddenly on a quick stop.

The (4) piece ramp set tucks under the rear wheels & is tied down
by ratcheting straps - this is a safety rear wheel chock method I use
on all vehicles where clearance allows.


Jim