The road to the 29-tonner is upon us, however reluctant
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British mixer operators are to travel down it. Steve Banner speaks to some of the converts.
A6.5m3 mixer barrel is about as big as you can expect to get onto a 6x4 26tonne chassis, so concrete mixer operators seeking to carry more product have been in something of a quandary Opting for a bigger barrel has usually meant speccing an eight-legger plated at 32 tonnes. But and 8x4 is more expensive to buy and to run, and an eight-wheeler's bulk makes entering and leaving some sites—and manoeuvring within them—somewhat problematic.
Some operators have concluded that a wiser route is to have a standard three-axle chassis converted into an 8x4 plated at 29 tonnes. By doing so you can fit a 7m3 barrel without having to compromise on its strength, and pay £2,000 less in vehicle excise duty than you would on a 32-tonner. But not everybody is agreed on which conversion works the best.
Last autumn Pioneer Concrete took delivery of seven Foden 3325 Tridem mixer chassis converted from standard three-axle chassis to 29-tonne 8x4s by Leyland-based Drinkwater Chassis Engineering. The conversions add a 3.5-tonne airsuspended Granning lifting mid-axle positioned 1,370mm ahead of the doubledrive bogie. The Fodens are fitted with 7m3 Leibherr mixers, and the Tridems only need to run with the lift axle down when carrying more than 5m3.
However, Pioneer has kept its options open. It has also ordered some 40 Scania 4Series 8x4s for use with 8m3 barrels on dedicated contract work at 32 tonnes.
The Tridem concept is well-established in the US and Scandinavia, but Drinkwater managing director Chris Drinkwater admits that it has not taken off as quickly in the UK as he had hoped. He has only built one other Tridem since the Pioneer Fodens were supplied, and that was for a building company. "It is fear of something that's new to the UK," he believes. "People have had the same attitude towards positively steered tag axles."
Potential Customers Another converter suggests that the lack of interest is because potential customers worry that Tridems will be difficult to manoeuvre on construction sites. An alternative route has been taken by Tarmac Topmix. It opted for an ERF 29-tonner built to a specification drawn up by ERF and Telford mixer manufacturer Hymix.
The ERF ES8.28 MX4 uses the same cab, suspension, and braking system as the ES8 6x4 that Tarmac Topmix acquired three years ago. It also employs the same Cummins C280 eight-litre engine, nine-speed syncromesh gearbox and twin-plate 356mm clutch, and is the same length as its stablemate.
The big difference is a second steer axle, which allows the vehicle to carry a newlydeveloped 7m3 Mixer.
Tarmac, Topmix and Hymix have also been working towards the same goal with Foden and Volvo. With the latter, the chosen vehicle is an FL7 8x4 B-ride chassis with a short (4.43m-wheelbase), which can comfortably accommodate Hymix's RD729 7m3 mixer.
With a kerbweight of just under 12 tonnes, the FL7 has a 13-tonne front bogie and a 19tonne rear bogie, with the gross weight limited to 29 tonnes by the outer axle spread.
Tarmac Topmix transport manager Bob Taylor is generally satisfied with the performance of his 29-tonners, and has several more on order.
"The results are not perfect," he says, "but we are very comfortable with them. We're trying to carry material at the lowest optimum cost, but a 32-tonner is really too big for our requirements. We run very few of them.
"The specification of the FL7 8x4, for example, more than meets our criteria," he adds. "It can carry substantially more product than traditional 6x4 configurations, has greater stability and manoeuvrability, and keeps operating costs in check too. It may well become the industry standard. Although I cannot see the entire Tarmac Topmix fleet going to 29 tonnes, in operational terms these vehicles compare very favourably with six-wheelers."
Other concrete mixer fleets are reserving judgment on the newcomers.
"We are aware of them, but we've not formed a definite opinion about them," says Tilcon transport manager Peter Rhodes. "We've made no commitment one way or the other."
Light aggregates Hymix managing director Nick Humpish is sure the road to 29 tonnes chosen by Tarmac Topmix makes sense. "I think a market is developing, and some of these trucks can carry as much as 8m3 of light aggregates," he says. "If you've got stiff concrete then much of the weight is imposed at the front of the truck, but if you're carrying wet concrete, it tends to be imposed at the back. But there's a lot of front-to-rear axle tolerance on a 29tonner–more than there is on a 26-tonner.
"Having two axles at the front gives you greater purchase when manoeuvring on-site, and the vehicle's manoeuvrability compares well with that of a 6x4," he adds. "OK, because you've got the additional axle you've got another set of brakes to maintain, but they're not doing as much work as they would be if they were fitted to a six-wheeler. The only drawback that I can see is that you've got the cost of an additional set of tyres to consider, although they shouldn't suffer from excessive wear."
Humpish argues that running 29-tormers makes sense on environmental grounds, because you can shift the same volume of product that you can with a fleet of 26tonners, but with fewer vehicles and drivers; and the driver shortage is starting to bite.
"And because you've got fewer trucks going on and off sites, that means there are fewer trucks for the site operators to deal with," he points out. "The site needn't be quite as busy and congested."
A further point in favour of eight-wheelers is the premium price they command when sold as second-hand exports. "There's a big demand for them in the South of Ireland, and I believe these customers will buy 29-tonners long-term," he says.
Good residual values help offset the additional front-end cost of acquiring an eight-wheeler, or having a six-wheeler converted. A Tridem conversion will set you back £5,000 to £5,500.
Construction industry Vulnerable to the peaks and troughs of the construction industry, the UK mixer market can vary from 200 units a year when times are tough to 800 when business is booming.
In theory the replacement cycle is five years, but in practice periodic downturns in activity mean that it is often stretched to eight.
Only 60 eight-wheeler mixer chassis were sold in 1996 compared with just under 500 six-wheelers, according to figures compiled by Leyland Daf. Last year eight-wheeler sales increased to 90, with six-wheeler registrations hardly moving.
Leyland Daf marketing manager Tony Pain believes he can detect an increased interest in 4m3 mixers on four-wheeler chassis. There's even the long-term possibility that the market could polarise at 4m3 and 7m3, although most observers agree that there is still plenty of life in the old 26-tonner.
Happily the market is stable at present, Humpish reports, and it looks set to remain so for at least the next 18 months to two years. Export sales have been affected by the strong pound, however–"we've survived relatively well, although it has made life a little difficult for us in the Republic of Ireland," says Humpish–which has also made life easy for the importers.
Undaunted, Hymix acquired rival Ritemixer 18 months ago. It is now the fourth biggest concrete-mixer manufacturer in Europe and the biggest in the UK. It produces up to 400 units a year, mainly for fitment to vehicle chassis.
Hymix production manager David Taylor believes that many operators currently running at 32 tonnes are now bound to go down the scale to 29 tonnes.
"There will still be room for a 6m3 sixwheeler, because operators don't always carry full loads," he says. "Obviously there's no point in running at 7m3 if you're only moving 3m3 to 5m3 at a time. But I believe 29-tonners are going to be popular. It's a very exciting development."