'Ubayd bin Jurayj radiallahu anhu asked Ibn 'Umar radiallahu anhu the reason for not wearing shoes with hair on them. He replied:
"I had seen Rasulullah Sayyidina Rasulullah sallallahu alaihe wasallam wear and perform wudu with shoes that did not have hair on them. That is why I also like this type of shoes" (DE)
English reference (DE): Book 10, Hadith 74 (DE)
Arabic reference (DE): Book 11, Hadith 78 (DE)