Как расширить поиск по размеру: ширина, вылет, dia?
Используйте фильтры:


function wf_search_et($et)
{
	if ($et === '') 
		return ['ui' => ''];

	return ['min' => $et, 'max' => $et, 'ui' => $et];
	return ['min' => $et-20, 'max' => $et+20, 'ui' => $et];
}

function wf_search_dia($dia)
{
	return ['min' => $dia, 'max' => 100, 'ui' => $dia];
}

function wf_search_width($width)
{
	return ['min' => $width-1, 'max' => $width+1, 'ui' => $width];
}


// Uncomment need custom filter

// search by car only
//add_filter( 'tyresaddict\wpfp\search\custom\car\et', 'wf_search_et' );
//add_filter( 'tyresaddict\wpfp\search\custom\car\dia', 'wf_search_dia' );
//add_filter( 'tyresaddict\wpfp\search\custom\car\width', 'wf_search_width' );

// for all searches - car & size
//add_filter( 'tyresaddict\wpfp\search\custom\et', 'wf_search_et' );
//add_filter( 'tyresaddict\wpfp\search\custom\dia', 'wf_search_dia' );
//add_filter( 'tyresaddict\wpfp\search\custom\width', 'wf_search_width' );