You can get nylon straps but I have found they rot over time. I prefer chain. Either weld them in place or weld them to a flat washer and run the shock bolts through them. Over time they will wear out and break also, but last longer than the straps.
I can’t believe every spread axle flatbed doesn’t have them, for when the crane operator snatches a big single off the deck.
For that you can dump the air out of the suspension, gravity will keep the suspension system flat: when picked up by a crane, the axles are hanging and therefore overextending the suspension via gravity.
Early 90’s I was hauling a lot of CSX freight. Wheels / axle sets were very common, 75 & 100 ton axles. Our 48x102’s were setup with air dumps to help unload the wheels. I used the handle of a binder to chock them until the forklift got back to grab another set. When loading I would dump the bags on the tractor, made it easier to roll them to the front of the trailer. Dumps on the trailers should have been installed on all of them, sadly they weren’t, but not all tractors had the controls either…..
Maybe to much weight on rear behind drive axle? Our single axle straight trucks that we leased for awhile had lift gates on the back and would buck and over extend the bags just hitting bridge and surface joints or quick changes in grade elevation through intersections. Always when running light weights. The extra weight on the back from the folded platform hanging way back behind the drive gave the truck a teeter totter effect. Heavy Weight directly behind the cab smoothed it out considerably. All our spring ride trucks would do the same bucking thing but never break or wear parts like the air rides and always felt more solid and firm like you weren't gonna roll over any second. I’ve never been a big fan of Air rides on straight trucks. To me they have always felt like sitting on a weeble wobble.
Shocks should be at least long enough to allow overextending the airbags till the top of the base can be seen. I’ve had that happen on Trucks and Trailers in the past. Once extended that far, the bags at risk of losing its seal and failing anyway. Broken shock shouldn’t be an issue, unless it’s getting stretched out so far above the base that the shock and airbag both get ruined.
The old Western Stars with Newsy suspensions had 2 leveling valves. One for each axle, plumbed separately, Some Owners swore by plumbing all 4 together. Not sure what was best. I wonder if dual leveling valves would help keep things level, and wheels all grounded, one for each wheel on a single axle. I never saw nor heard of the straps. Seems a piece of chain wrapped around each side of the axle, bolted to the spring hangers using the same bolts, with an extra nut might work.
Chain used as a limiter puts a lot of shock into the chassis and mounts, whereas limiting straps don’t. Straps stretch. As such, they’re meant to be mounted at a length to accommodate that stretch.
The fun part about limiting straps on shocks is you won’t break a shock, you just break the mount or shear the shock bolt off. If you put limiting straps on your shocks, reinforce the mounts. We regularly break 5/8” grade 8 shock bolts on our stretch rgns. I’d try to put a limit chain or cable separate from the shock.