Hi all

First time here go easy on me,

I have a Trek FX 7.1 with 700C tires
read 700x35 on the tire

I want to replace the entire tire and wheel with one that is labeled 700x28C for the sake of adding a electric hub motor to it,
I am just wondering if this will new tire/wheel will fit? as I no nothing of what these numbers mean, any insight would be more appreciated