hello I'm assuming that the rotavator is a engine over rota (merrytiller type) have you a photo I use A46 for merrytillers forward only no reverse on my merry tiller its a v belt the A is the section 46 is the length measure from pulley centre to pulley centre then double eg 23inch between pulleys double 46 belt length if you have the old belts take them to a belt supplier and get them to put it on their belt gauge it will be longer due to stretch jezza