I've never seen an official reason, but I suspect there's a legal issue in
California that prevents them from denying warranty coverage under the 10
year/100,000 mile warranty if your timing belt breaks after 4 years/60,000
miles (and it wasn't replaced).
Message posted using http://www.talkaboutautos.com/group/alt.autos.hyundai /
More information at http://www.talkaboutautos.com/faq.html