Shama-il Tirmidhi Chapter 10, Hadith Number 4 (74).

‘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”.

Commentary.
The reason for asking this question is that at that time it was it was not a general practice to wear shoes without hair on them. Imaam Bukhaari quotes a detailed hadith in his kitaab, where sayyidina Ubayd bin Jurayj radiallahu anhu said to Sayyidina Ibn Umar radiallahu anhu, “I see you observe a few things which the other sahaabah do not observe?” Among other question he asked the reason for wearing shoes with a smooth leather surface. sayyidina Ibn Umar radiallahu anhu made strong efforts to follow Rasulullah Sayyidina Rasulullah sallallahu alaihe wasallam in every aspect. The others generally wore the common leather shoes with hair.