how can i make a rar file into many smaller ones?

i use gdrive to send files to my friends and right now im trying to figure out how to rar a large into many smaller ones (gmail max limit is 10mb per file), so does anyone know how i could achieve this?

when you make an archive, you can have it split it into smaller files (options menu) - i dont know if you can easily split an already existing rar into smaller ones... you could always unpack & repack