Road Tests: Renault Kerax Highway

There is no doubting the durability and strength of the Kerax cab for off-road use – operators who bought one for gruelling muckaway work weren’t disappointed. But the multi-axle rigid market doesn’t stop at muckaway and deep quarry work. There are aggregates, asphalt and bulk feeds to consider, not to mention hook-loaders and skip-carriers, as well as the various niche markets like plant carriers and crane-equipped specialist vehicles. So there’s plenty of demand for something light and road friendly. Which brings us to the Kerax Highway. Renault trucks introduced its light and road friendly Highway line-up at the 2003 CV Show where it made no secret of the Highway’s ability to accommodate the magical 21-tone industry standard payload. The welcome weight loss involved the use of lighter parabolic leaf-spring suspension with an un-flitched chassis (which operators are advised not to use for arduous off-road work), and a road friendly driveline with a lower revving engine to improve fuel consumption. The eight-wheel Highway’s lost an impressive 750kg, and with the Premium chassis the 6x4 lost a full tonne. It’s sacrificed some ground clearance in the process, but remember you shouldn’t be taking a Highway too far off road in the first place.

There are 34 Highways among the 117 Keraxes sold in the UK so far this year. Market share for the 8x4 range is up a third to 5.25%’ the target is 10% within three years. These are no remarkable figures but Renault isn’t simply trying to gain numbers, it’s working at building long-term business. For this test Renault Trucks put forward a pretty standard vehicle. The engine, which it shares with the Premium tractor, is the dCi 11E: an 11.1-litre, six-pot charge cooled Euro-3 DI turbo-diesel featuring common-rail injection. The actual power output is a little lower than the ‘370’ tag Renault gives it. But its 356hp at 1,900rpm still equates to 11.1hp/tonne, which is more than enough for road use. Peak torque of 1,670Nm is on tap from 1,050-1,400rpm; that power and grunt is converted into motion through the propshaft by a manual ZF 16-speed overdrive gearbox with a PTO. While the 4.10:1 final drive isn’t exactly specced for long-distance haulage, with an overdrive top gear and 0.84:1 final drive, 1,500rpm equates to 90km/h on the motorway. When the Highway was launched the French made a lot of fuss about its 21-tonne payload potential but prospective buyers should note that this payload is only achievable with a day cab and a standard front axle. For this test we had the spacious but heavier Global sleeper cab and Wilcox aluminium insulated body and cover weighing in at 900kg. Other than that everything in the cab and fitted to the truck was standard except the air-con and the Jacobs engine brake.

It’s been a year since we last put an 8x4 through its paces, so the much talked about Highway is a welcome edition to the CM Hall of Records. And it has to be said that the Highway rates highly enough for a silver medal, coming in not far behind the early Euro-3 Scania P114340 we tested four years ago. The payload is competitive at 20,760kgbut in previous tests Daf, MAN and Scania tippers have all loaded more than 21 tonnes with aluminium bodies and day cabs. The Highway’s main plus is undoubtedly it’s A-road figure – a resounding 8.63mpg. Road friendly and economical, the Highway leads the Scania (the only other vehicle to break our 8mpg) barrier) and considering it’s been tested in its natural environment, it gets an A-double-plus. On the motorway we recorded 8.83mpg, which is significantly better than Volvo’s FM9 and MANs 32.364 but down on the Daf 75.320 and Scania P114.340, both of which broke nine. Warranty could be better as you only get one year/unlimited distance with the second year restricted to the driveline. That’s not too dissimilar to Volvo’s warranty on the FM9, but many other manufacturers offer two years/unlimited with a third year on the driveline. At £66,100 it’s competitively priced but price tags are relative; buy 20 and the pounds will tumble. The residual prices at three and five years aren’t as strong as the FM9’s.