function calculateSize() {
	// Gather form Data
	TireWidth = parseFloat(document.tireCalculator.tirewidth.value);
	AspectRatio = parseFloat(document.tireCalculator.aspectratio.value);
	RimHeight = parseFloat(document.tireCalculator.rimheight.value);
	
	// Calculate Tire Diameter
	resTireDiameter = (((TireWidth*(AspectRatio/100))*2)/25.4+RimHeight);
	
	// Calculate Tire Width
	resTireWidth = TireWidth / 25.4;
	
	// Display Results
	document.tireCalculator.resTireDiameter.value = Math.round(resTireDiameter*10)/10;
	document.tireCalculator.resTireWidth.value = Math.round(resTireWidth*10)/10;
	
	//calculateTires();
}

function calculateTires() {
	// Gather form Data
	TireWidth = parseFloat(document.tireCalculator.tirewidth.value);
	AspectRatio = parseFloat(document.tireCalculator.aspectratio.value);
	RimHeight = parseFloat(document.tireCalculator.rimheight.value);
	
	// Calculate Tire Diameter
	resTireDiameter = (((TireWidth*(AspectRatio/100))*2)/25.4+RimHeight);
	
	// Display Appropriate Results
	lightbox('tireResults');
	
	// show the first table
	if (TireDiameter <= 28) {
		document.getElementById('tire28').style.display = 'block';
	} else {
		document.getElementById('tire28').style.display = 'none';
	}
	
	// show the second table
	if (TireDiameter <= 32) {
		document.getElementById('tire32').style.display = 'block';
	} else {
		document.getElementById('tire32').style.display = 'none';
	}
	
	// show the third table
	if (TireDiameter <= 44) {
		document.getElementById('tire44').style.display = 'block';
	} else {
		document.getElementById('tire44').style.display = 'none';
	}
	
	// no tables, show contact message
	if (TireDiameter > 44) {
		document.getElementById('tireNone').style.display = 'block';
	} else {
		document.getElementById('tireNone').style.display = 'none';
	}
	
}