Great question Bryce.
These roadtrain guys in the outback only carry spare steer tyres as if a steer tyre blows, truck is grounded.
But if a rear tyre bows, the other tyre will take the load.
Saying that, if something bad does happen, some remote locations are over 6 hours wait for tyre service.
Funny enough, on these road train routes in the outback, the roads don’t really have anything on them to puncture a tyre.
These are very interesting roads as some of them are powder smooth as the years of trucks just pulverise everything in their way.
Truck tyres on these are of the highest rating you can buy and are almost impervious to anything, but steer tyres can’t be of this construction as they have to steer the truck, not just follow in a straight line.
Most of these trucks will have a big screen in the cabin with tyre pressure monitoring for all wheels, so they can keep an eye on the pressures & temperatures of each tyre.
Generally only under inflated tyres blow out as the extreme wall flexing creates excessive heat. Then a wall can blow out, or de lamination happens, which can be catastrophic on a fuel tanker, just a pain on non dangerous goods trucks.
Fuel tankers will also have a type of armoured mud guard to stop tyres when a failure happens from piercing the fuel vessel as they fly apart at a very high rpm.
A typical TPMS (Tyre Pressure Monitoring System) fitted to many trucks with multiple trailers.
Also a lot of big fleets now only run nitrogen in their tyres as it runs cooler, and have their own nitrogen trailers a staff member will use to check every single truck and trailer that enters the yard every day.
One big fleet here in Sydney has been doing this for over 10:years now, and have reduced their tyre failures by 75%, they also only run exclusively Michelin tyres on their trucks, and they get over $150 for every Michelin case they trade back to Michelin when they are worn out.
Michelin have their own recapping service and are the best re caps money can buy.
All done using genuine Michelin rubber and tread patterns.
https://michelintransport.in/why-recamic
Some smaller fleets run these as they are cheaper than new tyres for struggling fleet owners.