Just got into cycling and have a 1984 Peugeot p8 carbolite 103 road bike. I believe it's a p8 model but definitely carbolite 103 frame. I took off all the original components and now want to convert it to a beater/everyday single speed/ fixed. First question.. what is the size of the bottom bracket and is it possible to use a shimano bb-un54 for replacement? also what are some inexpensive, long lasting cranks i can start with?