Originally Posted by
reluctantsuburb
The originals are 27" but my wife's bike has 700c wheels, so I can temporarily steal to try fit out

Thanks!
Panaracer makes good quality 27 inch tires. You likely need wired on clinchers with those wheels. Check to see if the rim has a bead or a hook. If not, get wired on clinchers and don't pump them over 75-80 PSI.