• Three men in a bout with the 38-tonne limit
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Ice you have taken the ,cision to move up to 38 nnes and decided that 6x2 iits are the best solution ere are still plenty of
oices to make. Twin steer, If-steer, trailing axle, lifting le, factory-built or inversion? David Wilcox is spoken to three lerators who are treading is path and found that in ore than one case the anufacturers have failed, r one reason or another, to eet their needs. WITH 37 tractive units in the fleet B. J. Myers of Bermondsey, South London, specialises in providing traction in the UK, mainly for freight forwarders and trailer operators. The company also has 22 of its own trailers working mainly on unaccompanied services to Europe but operations director Tony Myers told me that the UK traction is the main part of the business.
When he heard that UK maximum weight was going up to 38 tonnes Tony Myers was not par
ticularly enthusiastic at first: "I thought most customers would want the extra load carried for the same money. I was afraid it could be another nail in the haulier's coffin."
But things have not turned out that way. The company has been fortunate to have the large forwarder, Mezario, as its main contract customer. Mezario has an enormous fleet of high specification, sturdy trailers (mainly Trailor-built tilts) running on tandem axles.
Being of Continental origin they are suitable for 38-tonne gcw operation and have a high kingpin load rating and widespread bogies. Mezario was therefore wanting its UK traction suppliers to come up with some three-axle tractive units and was prepared to give B. J. Myers a sufficiently good contract to warrant the investment.
Tony Myers therefore began to investigate the best way of achieving the 38-tonne limit with the 3+2 configuration. One of his first steps was certainly unusual and enterprising. Myers bought in Germany a 10-yearold MAN 20.320. This is a factory-built 6x2 unit with twin steer and Myers spent £6,000 on having it completely refurbished to a standard where one can quite easily believe the W-registration that it now carries.
"We had the MAN on the road working at 32 tons six months before the 38 tonnes came in on May 1. We were using it to check trailer compatibility and that sort of thing and see what the drivers thought of a 6x2 twin-steer."
Getting within the 15.5m overall length limit is no problem with the MAN because it is such a compact unit with an outer axle spread of only 3.6m. This limits the unit's UK maximum gvw to 20.33 tonnes rather than the top limit of 22.36 tonnes but Myers has not found this restrictive and have not encountered the kingpin loads of 12.5 tonnes plus that would overload it. Weighing in at around 7.7 tonnes this old MAN is not too heavy for a twin steer unit.
As a result of the early experience with the MAN Myers decided that the twin-steer arrangement was the best formula for a 6x2 unit. "We didn't like the idea of Scania's lifting rear axle. It seems rather a simple solution," said Tony.
And he was equally sure that he did not want conversions of 4x2 units — he had seen a variety of these on other hauliers' vehicles and was not happy with the standard of some of them.
He also felt that a full twinsteer conversion on existing units would mean sinking too much money into them. It had to be new, purpose-built twinsteers for Myers.
The company's first choice was the Daf FTG3300 DKX twinsteer 6x2 unit — Myers is a longstanding Daf operator and before it bought the MAN was 100 per cent Daf with 2800, 2300 and 2200 units.
"But we couldn't understand Daf's attitude. In this booklet they produce F.plaining the various options for 38 tonnes they seem to encourage the 2+3 combination and actually say 'the solution to the problem lies in the trailers'. That's an amazing thing for a tractive Ur)it manufacturer to say," said Tony Myers.
Daf's apparent unwirrigness or inability to satisfy the demand for a three-aiCle tractive unit in time for May 1 resultet directly in a substantial lost order from B. J. Myers. Despite being a loyal Daf customer the company could not get the 3300 twin-steer it wanted — "you saw it.:advertised but we couldn't get hold of one" — and so looked elswhere.
The Scania 112 was ruled out because of its lifting non-steering axle. The twin-steer Mercedes-Benz 2028 looked attractive but Myers wanted more power than the 206kW (276bhp) of the Mercedes — "We didn't really want to drop below 300bhp for 38-tonne work," said Tony. "We would probably have tried the 2033 Mere if it had been available." But Mercedes' programme dictates that the 2028 is its first 6x2 in this coun0 and the 246kW (330hhp) 2033 is not scheduled to arrive in the UK until next year.
Also on Mjlers' 6x2 short list was the 227kW (304bhp) Volvo F12 with its self-steering intermediate axle that locks in the straight-ahead position above 60km/h (37.3mph) or when reverse is engaged. The absence of linkages means the F12 is competitive on weight — around 7.6 tonnes for the sleeper cab model.
Although not exactly what Myers wanted the big factor in Volvo's favour was availability, and so, anxious to fulfil the Mezario contract and offer 38-tonne capability on May 1, Myers' first order for four 6x2 units went to Volvo instead of Daf. This meant that on May 1 the company had five 6x2 units on the road and this readifiess turned out to be a good move.
Tony Myers explained: "Some other operators seem to have been a little slow off the mark and we have had a lot of customers ringing us up because they want 6x2 units and have seen ours on the road. Not everyone has bought tri-axle trailers."
As a result of this response, Myers has bought a further four 6x2 Volvo F12 units and is considering taking on spot-hire ac well as contract work. '
Rates have also turned out to be better than Tony Myers feared. "I think customers see the 6x2 units and realise that we have had to make a big investment and so accept that 38tonne jobs will cost more. I don't think this would have happened if we were using 38-tonne 4x2 units and pulling their tri-axle trailers."
B. J. Myers still has more units to buy to complete its 38-tonne programme but does not feel tempted to opt for 38-tonne plated 4x2 units; it already has two Daf FT3300 4x2 units plated for the higher weight. "Pulling other people's trailers all the time, we don't know how they are loaded and it is too easy to get a drive axle overload on a 4e1x2 at 38 tonnes."
Because of that risk the company, where possible, leaves the front bay of a tilt empty when :using the 4x2 Dafs at 38 tonnes so that they gross at oaly around 37 tonnes.
Although the Volvos enabled Myers to be quick off the mark at 38 tonnes, Tony Myers is not entirely satisfied with them. He is a little suspicious of the self-steering axle arrangement and its ability to respond correctly to all situations. He also considers tyre wear on the drive-axle to be on the high side — they have worn down to 3mm tread depth within 50,000km — caused, he suspects by the drive-axle scrabbling for a grip when the units
pull away at 38 tonnes gross. Already 25 per cent of.MyE work is at 38 tonnes and l company expects this prop tion to have risen to 70 per c by the end of next year. This naturally entail the purchase more 6x2 units as the older 4; come up for replacement. Wh manufacturer gets the on may well depend on availabili
The well-known Derby-ba: haulage company F. B. Atli cannot view the 38-tonne lec lation so positively. Direc Michael Atkins complained t rates generally have not gone in step with the weights. 1 company's entry into the tonne business has been col spondingly hesitant and it I yet to take a final decision how best to achieve the tonne combination. So far, it hedged its bets and has so 3+2 combinations and so 2+3 combinations.
Early in the year Atkins tt delivery of a batch of tri-axle T lor platform trailers with I twistlocks, but its most rec move has been towards thr axle tractive units by way conversions.
"It is an engineering di sion," declared Michael Atki "We wanted 6x2 units for best load distribution." With 120 units (30 are based in CF bourg) and 325 trailers, Atk does a lot of container haulE and fears drive-axle overloi with front-heavy containers two-axle tractive units.
'Versions are cheaper than -.:tive unit conversions, when 3:1 trailer to unit ratio is ap;c1 the reverse is true. Michael ins said that the taxation aditages of the 3+2 configura1 did not figure prominently he decision (excise duty for a )-axle 38-tonne tractive unitis 940, wiljle it is £2,590 for a ee-axle unit).
inlike B. J. Myers, Atkins has far chosen to convert its exist
4x2 units rather than buy rpose-built 6x2. From its fleet Mercedes-Benz, Fiat, Seddon zinson and Scania units Atkins 3 to date had three Seddon zinson 400 units and a Scania ?converted.
he work has been carried out a small local company in rby, Dean's Engineering Seres, and entails moving the ye axle forward, extending chassis and then adding the :ra axle at the rear. This is a in, non-steering and nonng Rubery Owen-Rockwell :tern axle. Michael Atkins said was against a twin-steer ar!gement because of the result higher unladen weight.
he key part of the conversion he use of Norde rubber sus-ision for the extra trailing e and to replace the convenial leaf suspension on the ve axle.
;tan Dean of Dean's Engi;ring Services said that the vantage of this style of iversion is its simplicity and it the use of rubber suspen sion eliminates all suspension maintenance.
The replacement of the original drive-axle's heavy road springs with the Norde rubber system also gives a considerable weight saving which helps offset the additional weight of the new axle and longer chassis, Stan Dean said the complete conversion adds only 650-700kg so that the result should be one of the lighter 6x2 units on the road.
Another benefit of rubber suspension is that it allows a shorter chassis length for a given overall axle spread — with no spring hangers the chassis needs to extend rearwards very little beyond the additional trailing axle.
Because of this, the Dean's conversion on the Atkins units gives a generous 4m overall axle• spread for a fairly short chassis — only 23cm (9in) had to be added to the Scania 142 chassis, With the three Seddon Atkinson 400 units so far converted Atkins has occasionally experienced insufficient traction on the drive axle. To overcome this, Stan Dean is planning to add between each chassis side-member an air bag that can be inflated to increase traction when necessary.
The cost of the conversion is £4,300 plus the extra wheels and tyres — the airbag modification will probably add a further £150.
Dean's will be converting more of the Atkins fleet in future, although the company has also looked at factory-built 6x2 units; "the Daf 3300 looked good, but we don't want to mix up the fleet any more," said Michael Atkins.
As things stand, the company will probably continue to buy 4x2 and subsequently convert them — an unusual way of arriving at the 6x2 configuration but one which Atkins finds costeffective. A final decision will be taken some time in the New Year.
Transport Development Group company J. Spurling of Silvertown, London E16, has taken yet another path to reach its 38-tonne goal, but still believes that three-axle units and tandem-axle trailers are the best configuration. The company's technical director Ron Gooch said that he would feel decidedly unhappy operating at 38 tonnes with two-axle units.
Like Atkins, much of J. Spurlingrs work is container haulage and Ron Gooch also believed that there was too high a risk of drive-axle overloads with 4x2 units at 38 tonnes.
In addition to that he also expressed reservations about triaxle trailers from the point of view of tyre scrub and weight distribution — although the total weight on the tri-axle bogie may be legal, Ron Gooch questions the distribution of the weight on the individual axles.
With Spurfing's 135-strong fleet predominantly Scaniabased (81s and 82), the Scania 112 6x2 unit would seem to be the natural choice. But like Tony Myers, Ron Gooch said he is not so keen on the Scania 6x2 recipe using a lifting, single-tyred and non-steering axle. "It may be alright providing it is actually used. But I'm sure some drivers just do not bother to lift it when they should."
J. Spurting also has some Volvo F7 units which are used on the company's Honda motorcycle distribution contract but Ron Gooch was not inclined to move up the Volvo range for his 6x2 units — he is not enamoured with the F12's self-tracking intermediate axle and wanted full linked-steering.
The only way for Spurling to maintain its Scania policy and have twin-steer units was to convert. After talking to Scania, Spurling went to York Truck Equipment and between all three they came up with the first two twin-steer Scanias in the UK.
They are based on the P112MA 4x2 model, in sleeper cab form and on a 3.4m wheelbase chassis. Ron Gooch specified a 3.8m overall axle spread so that they would meet the maximum 22.36 tonne gvw limit. "I wanted to be able to get 14 tonnes through the kingpin if necessary," he explained.
All the conversion work on the two, brand new units was done at York's Corby factory and Ron admitted that it was an expensive way to achieve a 6x2 because the development costs had to be covered as well. York has done a particularly neat job of extending the Scania chassis and has fitted a Scania steering axle to serve as the new singletyred intermediate axle. This is suppprted by air suspension and located by semi-eliptic leaf springs.
The system incorporates a load-sensing valve to ensure the correct load distribution between the rear steer axle and the drive axle.
It seems to work; unlike the previous two operators J. Spurling has experienced no problems with loss of drive-axle traction and after 18,000km there are no signs of premature wear on the tyres.
Ron Gooch is a strong believer in spot-on wheel alignment helping to keep traction problems and tyre wear at bay. Although still new, both the 6x2 Scanias have been checked by Truck Align's laser equipment and adjustments subsequently made. Ron reckons that a regular check is money well spent.
During the York conversion the standard Scania fuel tank had to be shortened and so a catwalk tank was added to bring the total capacity back up to 485 litres (107 gallons). Complete• with a full load of fuel the twinsteer Scanias tip the scales at 8,000kg, giving a 24.6-tonne payload capacity when coupled up to one of Spurling's platform semi-trailers.
Originally York Big D fifth wheels were fitted on the Scanias but these resulted in a fifthwheel height of 142cm (56in) whereas the rest of the fleet is at 135cm (53in), so low-profile Jost versions were substituted.
Ron added that this compatibility not only makes coupling-up a safer operation but helps avoid the uneven weight distribution on the individual axles in the trailer's bogie that can occur if the fifth-wheel height is exces sive • In addition to the two Scanias (which were on the road for May 1) J. Spurling has had two other units converted to 6x2 guise. These are two T registration Seddon Atlinson 400 models used for container haulage on contract to ACL.
Lyka of Preston was entrusted with this conversion to twinsteer, which uses air suspension with quarter eliptic leaf springs. Lyka offers a cab-controlled dump-valve with this conversion to deflate the intermediate axle suspension for better drive axle traction but Spurling has not specified it and has not needed it.
The converted Seddon Atkinsons have an overall axle spread of 3.81m to maximise their kingpin load capacity for container work.
J. Spurling had the foresight to buy trailers suitable for higher weights as long ago as 1974 and so its fleet of 190 trailers (mainly platform and psk models) includes some with widespread 20-tonne tandem bogies and higher kingpin load ratings. The company also pulls many customers' trailers on container work which also conform to these specifications — another reason for choosing three-axle tractive units.
On some of its trailers the company is moving the landing leg position to 2.4m (7ft 11in) from the pin, a position on which it is standardising to avoid fouling on 6x2 unit chassis. J. Spurling finds that a 11 (44in) kingpin position is be though the trailers cum range from 40irt to 48in pin I ings. Ron Gooch added even with the 40in kingpin tion the 6x2 Scanias are in the 15.5m overall length limr Although the four conve units are all behaving s factorily, Ron Gooch wc naturally prefer factory-built units in the long term an earlier this month, corr4 with an A-plate, took delivei Dal's 3300 twin-steer 6x2, mingly the unit that operE want but until now have ft difficult to actually get. It m Ron Gooch's requirements he does not feel that the E 245kW (329bhp) is necessary thinks 209kW (280bhp) is riE the mark for 38 tonnes. The Scania 112 units have 22 (305bhp) while the Seddor kinsons have the Cummins option.
Ron Gooch said that the c !pany's 38-tonne work is "5 modic" at the moment an mainly newsprint and car foods on platform trailers. B' time goes by this is boun increase and J. Spurling wi wanting more 6x2 units to ac its current five.
Once again, who wins S. ling's valuable business gn depends on what the mant turers come up with and make available.
Ron Gooch would clearly Scania to produce the 11 twin-steer form. "We may I a lot of Scanias but if they dc come up with a 6x2 twinwe may be forced to look where." The lone Daf is evidi that this is not an idle threat.