60 inch bathtubs are measured framing to framing. So if your Alcove is 58" after backer board and tile you should have 60" to the framing in order to fit a standard tub in. Otherwise you can just buy a 58" bathtub. They can be difficult to find but are available. 54c bathtubs are pretty easy to find as well so that may be an option. It's easier to make an opening smaller than to make it larger.
AffectionateAd4985 t1_j2ehw48 wrote
Reply to Replacing tub with one 2in longer? by brandolinium
60 inch bathtubs are measured framing to framing. So if your Alcove is 58" after backer board and tile you should have 60" to the framing in order to fit a standard tub in. Otherwise you can just buy a 58" bathtub. They can be difficult to find but are available. 54c bathtubs are pretty easy to find as well so that may be an option. It's easier to make an opening smaller than to make it larger.