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<SCRIPT LANGUAGE="JavaScript">
<!-- hide the script contents from old browsers
function tireCalc(form) {
var aspectstk = form.aspectstk.value;
var widthstk = form.widthstk.value;
var wheeldiamstk = form.wheeldiamstk.value;
var tirediamstk = form.tirediamstk.value;
var aspectalt = form.aspectalt.value;
var widthalt = form.widthalt.value;
var wheeldiamalt = form.wheeldiamalt.value;
var tirediamalt = form.tirediamalt.value;
var percentdiff = form.percentdiff.value;
{
tirediamstk = (aspectstk / 100 * (widthstk * .03937) * 2) + (wheeldiamstk * 1);
tirediamalt = (aspectalt / 100 * (widthalt * .03937) * 2) + (wheeldiamalt * 1);
percentdiff = (tirediamalt - tirediamstk)/tirediamstk;
form.tirediamstk.value = Math.round((tirediamstk) * 10) / 10;
form.tirediamalt.value = Math.round((tirediamalt) * 10) / 10;
form.percentdiff.value = Math.round((percentdiff) * 1000) / 10 + "%";
}
}
// done hiding -->
</SCRIPT>
<H2>Tire Size Calculator</H2><P>
This tool is provided to assist you in evaluating alternative tire sizes for
your vehicle. Simply insert the stock tire size recommended by the vehicle manufacturer
in the left column and the alternate size you are considering into the right column. Click "Compute" to see the overall tire diameters and the percent difference between the two.<BR>
<BR>
<b>
Note -</b> To avoid potential problems with ABS and traction control (ASR, ESP) you should always maintain overall tire diameter within
plus or minus 3% of stock. This tool only addresses the issue of tire height. IT DOES NOT address the issue of tire width or any interference with the inner fender.
<BR>
<HR>
<BR>
<form name="tireCalculator" method=get>
<table border="0" cellpadding=5>
<tr>
<td></td>
<td align=center><b>Stock</b></td>
<td align=center><b>Alternate</b></td>
</tr>
<tr>
<td align=right>Tread width (mm):</td>
<td align=center><input type=text name=widthstk size=8 value=" " onFocus="select()"></td>
<td align=center><input type=text name=widthalt size=8 value=" " onFocus="select()"></td>
</tr>
<tr>
<td align=right>Aspect Ratio:</td>
<td align=center><input type=text name=aspectstk size=8 value=" " onFocus="select()"></td>
<td align=center><input type=text name=aspectalt size=8 value=" " onFocus="select()"></td>
</tr>
<tr>
<td align=right>Wheel diameter (inches):</td>
<td align=center><input type=text name=wheeldiamstk size=8 value=" " onFocus="select()"></td>
<td align=center><input type=text name=wheeldiamalt size=8 value=" " onFocus="select()"></td>
</tr>
<tr>
<td colspan=3 align=right><input type=button value="Compute" onClick="tireCalc(this.form)"></td>
</tr>
<tr>
<td align=right><b>Tire diameter (inches):</b></td>
<td align=center><input type=text name=tirediamstk size=8 value=" " readonly></td>
<td align=center><input type=text name=tirediamalt size=8 value=" " readonly></td>
</tr>
<tr>
<td align=right><b>Difference:</b></td>
<td></td>
<td align=center><input type=text name=percentdiff size=8 value=" " readonly></td>
</tr>
</table>
</form>
Results within <u>+</u>3% of stock are considered acceptable.<BR><BR><HR>
Tire sizes are expressed by the manufacturers with three sets of numbers:<BR>
Tread width - Aspect Ratio - Wheel diameter (e.g. 215 55 16)
""