Unfortunately your question has no precise answer to it since we simply do not know.
However there are two traditions in the West as to what constituted the robe(s) of Jesus.
Their is the Tier tradition as regards the Seamless robe of Jesus:
According to legend, Helena, mother of Constantine the Great, discovered the seamless robe in the Holy Land in the year 327 or 328 along with several other relics, including the True Cross. According to different versions of the story, she either bequeathed it or sent it to the city of Trier, where Constantine had lived for some years before becoming emperor. (The monk Altmann of Hautvillers wrote in the 9th century that Helena was born in that city, though this report is strongly disputed by most modern historians.)
And there is the Argenteuil tradition:
According to the Argenteuil tradition, the Empress Irene made a gift of the seamless robe to Charlemagne in about the year 800. Charlemagne gave it to his daughter Theocrate, abbess of Argenteuil,1 where it was preserved in the church of the Benedictines. In 1793, the parish priest, fearing that the robe would be desecrated in the French Revolution, cut the robe into pieces and hid them in separate places. Only four of the pieces remain. They were moved to the present church of Argenteuil in 1895.
The earliest document referring to the robe at Argenteuil dates from 1156, written by Archbishop Hugh of Rouen. He described it, however, as the garment of the child Jesus. A long-running dispute claims that the Argenteuil cloth is actually not the seamless robe worn by Jesus during the crucifixion, but the garments woven for him by the Virgin Mary and worn his entire life. Advocates of the theory that the Argenteuil cloth is the seamless robe claim that the Trier robe is actually Jesus's mantle.
What is a mantle?
A mantle is a type of loose garment usually worn over indoor clothing to serve the same purpose as an overcoat. Technically, the term describes a long, loose cape-like cloak worn from the 12th to the 16th century by both sexes, although by the 19th century, it was used to describe any loose-fitting, shaped outer garment similar to a cape. For example, the dolman, a 19th-century cape-like woman's garment with partial sleeves is often described as a mantle.
Whether or not Jesus wore a tunic and a mantle or simply a tunic, we do not know. The towel with which He was girded was certainly tied around His waist as we would ware a leather belt.