Ciao, devi usare il custom-control piu una modifica al foglio di style.

codice:
 .custom-control-input:checked~.custom-control-label::before {
            border:0;
            background-color: red;
        }
codice HTML:
<div class="custom-control custom-radio custom-control-inline">
        <input type="radio" id="radio1" class="custom-control-input" name="radio" value="radio1" checked>
        <label class="custom-control-label" for="radio1">Radio 1</label>
    </div>

    <div class="custom-control custom-radio custom-control-inline">
        <input type="radio" id="radio2" class="custom-control-input" name="radio" value="radio2">
        <label class="custom-control-label" for="radio2">Radio 2</label>
    </div>