When Foodstuffs supermarket transport contractor AF Logistics pondered fitting air suspension to their new Isuzu 6x4 tractors to improve ride and protect fragile cargo, they never realised it would create a world first. Neither did Deakin Engineering of Hastings, who prepared all the AF Logistics trucks for their task of transporting food to New World and Pak ‘n Save supermarkets around the lower North Island. Nor did their suspension supplier, Hendrickson. To their surprise, no EXZ460R Isuzu trucks in any other markets had been converted to PRIMAAX air suspension, due to various engineering issues. So, with typical Kiwi nonchalance they decided to do it anyway. Six months later AF Logistics had three Hendrickson PRIMAAX air-suspended Isuzu EXZ460R tractors that are unlike any in the world and they couldn’t be happier. Sounds simple, but it took the design team at Hendrickson and the practical know-how of Deakin Engineering to make it happen. Pat Duncan, National Sales Manager for Hendrickson’s New Zealand operations, says the PRIMAAX air suspension typically goes on big American iron and premium European trucks, being ideal for coping with the extra torque. Most air conversions tend to go onto trucks that spend some time off highway or are used in specialist applications where air offers advantages with ride and traction. Japanese trucks tend to run mainstream delivery work and normally use conventional suspension set-ups, which is why no one had ever looked at air for an Isuzu before. Pat admits to being intrigued when he first got the call from Allan Street at Deakin Engineering, especially when he couldn’t find any examples of similar applications when he enquired with the Hendrickson team in Australia and then the US headquarters. “We were surprised that it hadn’t been done anywhere else, but we reckoned it could be done, so we put our heads together with Deakins and made it work,” says Pat. Hendrickson looked at several solutions, including using their HAS air system, but quickly realised that PRIMAAX was the answer. The biggest stumbling block was the location of a big retarder on the front diff – only a PRIMAAX would fit. Allan Street explains: “We considered other air suspension units but they were not suitable because of the retarder placement with the 460 model. “We decided PRIMAAX was the way to go because it is easier to fit and, being made for heavy-duty applications we weren’t going to have vibration issues.” Having agreed on the PRIMAAX units, Hendrickson engineers drew up schematic blueprints for the conversion and Allan and his team got to work. Hendrickson NZ had two PRIMAX 460 suspensions in stock that had been engineered to suit Nissan CG450 trucks but as these were needed to fit the ISUZU we adapted these to suit. He said: “We had to do some of our own modifications to make it work, such as the shock mounts and we swapped the brake chambers on the rear diff from left to right so we could clear the air bags. And it enabled us to lower the suspension to 950mm chassis height, which helps with the truck stability and fifth wheel height. “Although we had to make some adjustments, the PRIMAAX system is actually quite simple to fit and there is still plenty of movement in the suspension. The trucks have been on the road for more than four months now and they’re running very well - AF Logistics is very pleased with their performance. “It’s nice to think we’ve done something that no one else in the world has.” The pioneering work of the New Zealanders has already raised considerable interest internationally, with Hendrickson of America and Isuzu engineers in Japan showing keen interest. Keith Ward, Director of New Business with Hendrickson Asia Pacific is planning to take the details of the conversion to Japan on his next visit to Isuzu.