Originally Posted by
2manybikes
27" tires and 700c wheels are not compatable.
Find a tire with a Kevlar bead, That will help a little. Spit on your finger and wipe the part of the rim that the tire is climbing over with saliva, lubrication helps everything. It works even better when putting them on. A little drop on you finger and then spread dish soap on the outside wall helps a tough tire go on, just be sure to leave no residue so the brakes will still work. You can put a little on the inside of the tire that is climbing over the wall too. Just a little. Windex works too and evaporates cleanly.
There really is no good way to know before buying how they fit, wheels and tires all vary a little.
I keep a couple of painter's moist grease wipe towelette thingies in a ziplock bag in my saddlebag tire repair kit. You can use them to wipe the inside of the tire to check for the offending thorn, wet down the tire bead when mounting, and then clean the crud off your hands when finished.