Before modifying a set of adjustable
BAL Standard Tire Locking Chocks so they would fit between the tires on our Coachmen trailer I used rubber chocks (for Canadians,
from Princess Auto) which were secured in place with hardwood spacers.
This worked quite well as the spacer would prevent the chocks from shifting in any way so the trailer couldn't roll forward, couldn't roll backward. Had I not been able to shorten the BAL chocks to fit, this rubber chock / spacer method would still be my preferred method of securing the trailer so it absolutely can't inadvertently shift. :B