function calc_mountenbike ()
{
	steplength = document.mountenbike.steplength.value;
	if (isNaN (steplength.replace (",", ".")) === true)
	{
		document.mountenbike.steplength.value = 0;
		steplength = 0;
		alert ('Der Eintrag in der Spalte Schritthöhe hat ein ungültiges Format!');
	}		
	document.mountenbike.sizeinzoll.value = (Math.round (steplength * 0.226));
	document.mountenbike.sizeincm.value = (Math.round (document.mountenbike.sizeinzoll.value * 2.56));
}
function calc_fullsuspension ()
{
	steplength = document.fullsuspension.steplength.value;
	if (isNaN (steplength.replace (",", ".")) === true)
	{
		document.fullsuspension.steplength.value = 0;
		steplength = 0;
		alert ('Der Eintrag in der Spalte Schritthöhe hat ein ungültiges Format!');
	}		
	document.fullsuspension.sizeinzoll.value = (Math.round (steplength * 0.225));
	document.fullsuspension.sizeincm.value = (Math.round (document.fullsuspension.sizeinzoll.value * 2.56));
}
function calc_racingbike ()
{
	steplength = document.racingbike.steplength.value;
	if (isNaN (steplength.replace (",", ".")) === true)
	{
		document.racingbike.steplength.value = 0;
		steplength = 0;
		alert ('Der Eintrag in der Spalte Schritthöhe hat ein ungültiges Format!');
	}		
	document.racingbike.sizeracingbike.value = (Math.round (steplength * 0.665));
	document.racingbike.sizetriathlonbike.value = eval (document.racingbike.sizeracingbike.value) - 4.25;
}
function calc_sporttouring ()
{
	steplength = document.sporttouring.steplength.value;
	if (isNaN (steplength.replace (",", ".")) === true)
	{
		document.sporttouring.steplength.value = 0;
		steplength = 0;
		alert ('Der Eintrag in der Spalte Schritthöhe hat ein ungültiges Format!');
	}		
	document.sporttouring.sizeinzoll.value = Math.round (steplength * 0.24);
	document.sporttouring.sizeincm.value = Math.round (steplength * 0.61);
}
function calc_trekkingbike ()
{
	steplength = document.trekkingbike.steplength.value;
	if (isNaN (steplength.replace (",", ".")) === true)
	{
		document.trekkingbike.steplength.value = 0;
		steplength = 0;
		alert ('Der Eintrag in der Spalte Schritthöhe hat ein ungültiges Format!');
	}		
	document.trekkingbike.sizeinzoll.value = Math.round (steplength * 0.259);
	document.trekkingbike.sizeincm.value = Math.round (steplength * 0.66);
}