The indication /80 is a standard size and is therefore often omitted. So it is the same size as the 155/80R13. Also available with a black edge. Read here how to measure the size of the hole circle. (https://www.remorqueshop.fr/roues-et-rims/roues-completes/) What do all tire specifications mean? Consult the explanation here (https://www.remorqueshop.fr/roues-et-jantes/)