Originally Posted by
kardar2
If your tire is low in the rim in some places, which often happens on rims with inside shoulders requires lowering pressure to minimum to keep shape, and massaging the tire toward the low spot and pulling it up by rolling the tire away from the rim at the spot. Sometimes if you get it close, it pops up on it's own as you inflate.
Tried this I can't get it rool up on the lip
This used to be a common problem, and we hear less of it these days because most modern rims are hook edge, not "Endrich" pattern with shoulders. Many years ago both Park, and Bicycle research made tools which were essentially big dull pliers for grabbing low spots and pulling them up. I don't know if the tools are still made, but you can DIY your own with something to protect the tire, such as thin blocks of wood, or flat metal, section of old leather belt, or maybe even popcycle sticks. Use a pair of Channellocks, to grab the tire through the protection and roll it up and out.
BTW- some modern tires are made for hook edge rims and less attention is paid to the ID at the bead. These can be a bit undersized and may never seat properly by the shoulders.