However, adding weight behind the rear wheels was said to adversely affect steering and handling. For 1957 the Thunderbird's trunk was stretched  to allow the spare tire to migrate back inside, although the continental mounting was still optional.
It was noted that adding weight to the rear wheels would have a detrimental effect on steering and handling. In 1957, the Thunderbird's trunk was modified to accommodate the spare tire in a more compact manner, while the option for a continental mounting remained available.