I have already tested and tried the best of Schwalbe's product line as of 2019 and not seen anything close to thick enough for my environment.
I have measured the largest goathead i have seen on the road, and it was about 11mm.
In 'murica units, that's almost 1/2 an inch. Therefore that '5mm' of 'protection layer' plus the 2mm of regular rubber leaves us with 7mm of protection.
A typical tube is 1-2mm thick and so we have a total of 9mm of rubber in the best case.
But when you sit on the bike, this rubber compresses, so we're probably talkin' ~7mm.
And given that a goathead is much harder than the rubber tire and can be 11mm in length, we're just a few millimeters short on rubber.
We either need more hardness or more rubber.. pick your poison... but the best bicycle tire is not adequate for those who live in
goathead hell.
The one thing i haven't experimented much with is very thick tubes.
Let's say i find one 4mm thick and put it in a 7mm thick tire.. i have 11mm of rubber... until it compresses.. :/
.. and horrible rolling resistance..
..see, this is how we end up with motorcycle tires with horrific rolling resistance. They are the
bare minimum to ensure that during each ride, i am not replacing or patching an inner tube every 10 miles on average.
Mr tuffys and stop flats both wore my tire's tubes ( possibly they shifted around during times that air pressure was low ) away and created a flat in them. I tried tire in a tire and the tire held up but had horrible 'handling characteristics' ( lots of side to side motion in the tire itself ). That's unnerving at high speed.
Slime is probably the best product on the market for flat protection still. But the energy loss from cavitation is wild. For me, it reduces the possibility of a flat but doesn't eliminate it.
Really.. there aren't any good 'bicycle' answers out there i think.
Tubolito's tubes are said to be twice as strong and have lower rolling resistance due to their use of fancy new materials, but this is not enough to protect me from the last couple millimeters of goathead trying to work their way through.
I think a motorcycle tire is the minimum for riding in this area until there's a real silver bullet for the bike tire situation.