Due to the different bike and riding style adventure bike rides will have a different grading system to normal AMTRA rides.
Level 1,
Easy dirt roads only, plenty of tar, suit all bikes including 1000cc plus bikes. Road tyres ok.
Level 2,
Easy dirt roads, some easy trails, at least 50% plus tar road riding. Road tyres ok, but aggressive tyres an advantage. Big bore multi cylinder bikes ok.
Level 3,
50% road/ off road mix, medium trails possible, off road tyres highly recommended. Twin cylinder bikes ok if rider skill is high.
Level 4,
Mostly dirt and medium to hard trails, off road tyres needed, not recommended for big twin cylinder bikes. High skill levels needed.