On Saturday, September 2, 2017 at 7:44:58 AM UTC-7, Joerg wrote:

Thanks. Tyrfil is what Andrew brought up and I'll contact them next week.

I'd like to have a similar firm tire behavior as if it was pumped up
with air to 110psi. Riding comfort isn't very important, durability is.

I'll give you a prediction - you'll discover that weight is a big problem and that you can't get the tire to properly stay in place.