On Thursday, August 31, 2017 at 11:55:06 AM UTC-7, Joerg wrote:
Yesterday I had another two (!) sidewall punctures. Long story short I
will definitely not recommend CST Conquistare tires. Wore out in less
than 1200mi and then weakened which is just unacceptable. So thumbs down
from me.

This brings up two questions:

1. The Mr.Tuffy orange liners for 700c narrow tires. They must be laid
in with a wee overlap. Will that overlap cause a 700c 25mm tire at
110psi to run bumpy? Like whop .. whop .. whop every time the overlap
comes around?

2. What about taking a second (otherwise discarded) thorn-resistant
tube, slit it open on the inside and slide it over the real
thorn-resistant as a 2nd layer?

The problem is that Kenda seems to have discontinued selling
thorn-resistant tubes with good and most of all same thickness all
around but now the thickness tapers off towards the sidewalls. That's
where they fail. Same for Sunlite which I had to re-order yesterday
because those things are essentially unfixable with those thin REMA patches.

Any words of wisdom? As usual, weight absolutely does not matter.

In case anyone knows: I read somewhere that smugglers "inflate" their
vehicle tires with some sort of hardening sealant (Silicone?
Construction foam?) that makes the tires bullet-proof. What material is
it and how do they get it in there thoroughly enough? Would it be good
for a couple of thousand miles?

As usual - no. Weight from Mr. Tuffy's is insignificant. Construction foam would cause a tire to fail almost immediately. First by breaking it up into chunks and then collapsing it.

There is tubeless tires and sealant but these will not handle cuts or tears in the sidewalls of fat tires. If you can get the tube type from which you can extract the presta fitting then you can put in large amounts of sealant into the tube. When using this sealant you have to always stop or park the bike with the fill on the bottom of the wheel.

All presta valves used to screw out but the times I've tried it recently was on cheap tubes and they were somehow fixed inside the nozzle.