<?php
$xml = <<<XML
<?xml version="1.0" encoding="UTF-8" ?>
<bikes>
    <bike>
        <model>First</model>
        <speedNumber>4</speedNumber>
        <sizes>100</sizes>
        <amount>100</amount>
    </bike>
    <bike>
        <model>Second</model>
        <speedNumber>3</speedNumber>
        <sizes>300</sizes>
        <amount>150</amount>
    </bike>
    <bike>
        <model>Third</model>
        <speedNumber>4</speedNumber>
        <sizes>300</sizes>
        <amount>300</amount>
    </bike>
</bikes>
XML;
$bikes = new SimpleXMLElement($xml);

echo $bikes->bike[0]->model . "\n";
echo $bikes->bike[0]->speedNumber . "\n";
echo $bikes->bike[0]->sizes . "\n";
echo $bikes->bike[0]->amount . "\n";

?>

First
4
100
100