Steve I'm a little confused about preloading and unloading.Could you be so kind as to put this in numbers as in.
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This looks really helpful because I've had to jump on the tailgate to get the ball off a time a two.
You want the chocks to be really secure "under" the tires - not just kicked into place and squirming around loose on the ground. You want a chock in front of one tire on each side of the trailer, and a chock in back of one tire on each side of the trailer.
1 - get the trailer positioned where you want it
2 - place a chock behind one tire on each side of the trailer
3 - back up slightly but not too much, just enough for the tires to put a little load on the chocks but not enough to squish them, and then use the tow vehicle brakes to keep it right in that position
4 - place a chock in front of one tire on each side of the trailer and give each chock a good kick so it's hard up against the tire
5 - release the brakes and let the tow vehicle go 'loose', so the trailer tires can settle in and be cradled between the chocks
6 - the trailer is now 'pinched' between the chocks, and not only is less likely to roll around, but this will also help lessen the lateral loading on the stabilizer and tongue jacks and you'll feel the trailer moving around a lot less as you move around inside after unhitching.
This won't particularly help with unhitching when the ball is stuck in the coupler socket, but I have found that it helps having the trailer locked in to place when I need to go forward or backwards ever so slightly to get the ball positioned exactly between the sliding plate and the lip on the front of the ball socket so it can clear the coupler when raising the tongue to unhitch.