Fuel was stored in tanks running down the side of the chassis, above the driver's legs and behind their seat, totalling capacity. Full capacity was not required for most races so the tank above the driver's legs was usually almost empty. For the M7A's first two world championship races, Bruce McLaren's car was fitted with outboard "pannier" fuel tanks at the side of the cockpit. McLaren had a theory that sports racing cars' handling was superior to that of single-seaters because of the weight distribution of their fuel; the pannier tanks were an attempt to replicate this. According to McLaren mechanic Tyler Alexander this idea was developed in discussion with Lotus boss Colin Chapman. After the car was damaged at the 1968 Monaco Grand Prix, it was rebuilt without the pannier tanks.