Thanks for your question regarding rust spots on your Chanticleer pear tree. There are a couple of strategies we recommend to manage your situation now and also to prevent rust on your pear next year. Timing is critical to control rust since fungicides need to be applied preventively in the spring.

Rusts have complicated life cycles and usually have a secondary host, in the case of your pear, it is probably a juniper or cedar tree. This can be up to 1/2 miles away, so it can be hard to avoid, but, if you have one in your yard, you may want to monitor it as well for orange galls in the spring (there's a pic in the Kansas State pdf).

What you can do now would be to use some management strategies, such as avoiding overhead watering, thinning to increase air circulation, and raking up and removing infected leaves in the fall. Please take a look at the Colorado State University (Plant Talk) link below for more details.

Plant Talk:
https://planttalk.colostate.edu/topics/insects-diseases/1400-22-foliar-rusts-leaves-plants/

K-State pdf:
https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=&ved=2ahUKEwi21ujuqb3yAhUDK80KHW-zBMEQFnoECAQQAQ&url=https%3A%2F%2Fhnr.k-state.edu%2Fextension%2Finfo-center%2Fcommon-pest-problems%2Fcommon-pest-problem-new%2FPear%2520Rust.pdf&usg=AOvVaw1RIuq3Ugdni4b_1g5j4nxh

Best of luck