Contradiction with Mark 15:21
Mark mentions Simon of Cyrene carrying the cross, while John 19:17 states Jesus bore it himself.
Mark 15:21: And they compel one Simon a Cyrenian, who passed by, coming out of the country, the father of Alexander and Rufus, to bear his cross.
Contradiction with Luke 23:26
Luke similarly describes Simon of Cyrene carrying the cross, contrasting with John 19:17 where Jesus carries it alone.
Luke 23:26: And as they led him away, they laid hold upon one Simon, a Cyrenian, coming out of the country, and on him they laid the cross, that he might bear [it] after Jesus.
Contradiction with Matthew 27:32
Matthew also records that Simon of Cyrene was compelled to carry the cross, differing from the account in John 19:17.
Matthew 27:32: And as they came out, they found a man of Cyrene, Simon by name: him they compelled to bear his cross.