Imran bin Husayn passed by our mosque, so I rose and took hold of his bridle and asked him about prayer during travel.He said, "We went out with the Messenger of Allah ﷺ on Hajj, and he used to pray two rakahs until he passed away, Abu Bakr prayed two rakahs until he passed away, Umar prayed two rakahs until he passed away, and Uthman prayed two rakahs for six or eight years, then he completed the prayer at Mina as four."
حدثنا محمد بن جعفر حدثنا شعبة عن علي بن زيد قال سمعت
مر على مسجدنا عمران بن حصين فقمت إليه فأخذت بلجامه فسألته عن الصلاة في السفر فقال خرجنا مع رسول الله ﷺ في الحج فكان يصلي ركعتين حتى ذهب وأبو بكر ركعتين حتى ذهب وعمر ركعتين حتى ذهب وعثمان ست سنين أو ثمان ثم أتم الصلاة بمنى أربعا
Its chain of transmission is hasan due to Ali bin Zayd. The hadith previously appeared at 19751. His saying "by its bridle" means by the bridle of his mount.