Complex sentence: In standard form the spare wheel was carried hidden on top of the rear mounted fuel tank but either version could carry one or two side mounted optional spares this to allow the use of a 40 gallon long distance fuel tank.
Split into simpler sentences: In standard form the spare wheel was carried hidden on top of the rear mounted fuel tank but either version could carry one or two side mounted optional spares. This allowed the use of a 40 gallon long distance fuel tank.