I would see if gaerlan can get you something .I checked with schwalbe at the chicago bike show and in 14 inch all they make are tires rated to 45 psi .You should be able to get some pretty good tires in 16 inch though .I have a bike with 14 inch tires and the best i was able to get was 55 psi. I would not even bother with a bike with 12 inch tires.i have looked at the 12 inch tires on strollers at rei and they are only rated to 35 psi.What will you use the tires for?