coa - Lar ROADTEST
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For an extra .E1,000, it gives you more ratios for fine-tuning on the hills.
Behind the GRS900 is a 430mm-diameter single-dry-plate clutch. At the end of the propshaft is the 13-tonne-capacity air-suspended Scania ADA90 back axle with it R780 single reduction hypoid gear.
With a standard 4.3:1 ratio the R143-420 has a maximum geared-speed of 67mph. As with all new tractors this was limited to 56mph (90km/h). There is a faster 3.08:1 ratio with a geared speed of 74mph.
The gearbox-mounted Scania retarder can be operated by a five-position hand lever or, in automatic mode, by the brake pedal. TO select automatic the driver flips a rocker switch on the dash. As the pressure on the brake pedal is increased the retarder's electronic control box also activates the conventional butterfly-type exhaust brake to provide yet more retardation. As with a conventional exhaust brake, the retarder works best when the engine revs are high.
However, the Scania retarder has a trick up its sleeve: it provides constant downhill speed control. Once you're at the required speed, simply press the button at the end of the hand lever and the retarder's ECU takes over, dialling in the retarder and exhaust brake as required. The heat generated by the hydrodynamic retarder is dissipated through the truck's cooling circuit.
The aerodynamic "Streamline" cab, first offered as an option in 1991, is now standard on all R-range tractors. Our R143 also sported the Topline high-roof extension which gives an extra 220mm of headroom. With the Topline you get seat-mounted seatbelts, cen
tral locking, headlight wash/wipe and an airsuspended passenger seat which slides right back to leave bags of room in the footwell.
Put it all together with Scania's build quality and you've got a tractor that has long been admired by UK buyers, But how does it fare against more modern rivals?
• PRODUCTIVITY Volvo can stop worrying. Its FH12-420 still holds our 38-tonne fuel title at 839mpg and will probably do so for some time yet (CM 1824 August 1994). The gap between the FH12 and its nearest rivals is currently so big that it almost seems unfair to compare it with other 420hp tractors.
Before testing the Volvo, we reckoned that any 400hp-plus tractor that could get close to 7.5mpg was doing alright: around our 1,180km Scottish route the R143-420 returned an average 7.3mpg (38.71it/100km). That's not bad when you compare it with other 14-litre Scania artics tested by CM—the R143-500 managed 7.15mpg; the pre-Euro-1 470 and 450 delivered 7.2 and 7.01mpg respectively.
So if the 420 performs well against its higher-powered stablemates, how does it do against other 420hp marques? Not so well is the answer, although the margin is nothing to write home about. The ERF EC.41, MAN 17.422, Leyland Daf 95.430 and Mercedes 1844 all beat the Scania, but none by more than 0.2mpg. Ifs worth noting that CM s Scottish route was lousy with roadworks, from the M6 right round to the Ml. All those cones do nothing for fuel consumption, or average speed, although at 7119krnih, the R143-420 has nothing to be ashamed of.
The Scania did manage one notable scalp: Iveco's 400E42 EuroTech could only manage 7.15inpg. And when it comes to economy on tough motorway running it consistently delivered more than 8.5mpg running hard up against the limiter. On the southbound leg on the M18 and M1 only the FH12-420 did better.
Clearly, if you're looking to haul maximum weight, Scania needs to put the 143 on a diet. With a kerbweight of 736 tonnes our R143420 is no featherweight—although that figure does include 120kg for the retarder, 70kg for the Topline extension and 400kg for fuel in a second 4001it tank you might not need. If you do, you'd better look at alloy wheels.
• ON THE ROAD If Ariston ever make a truck, chances are it'll be the R143-420. On dual carriageways and motorways, it just goes on and on and on. We loped up Shap in top up against the limiter, hardly breaking into a sweat. At 90krn/h the big vee-eight is burbling along at around 1,600rpin, well within the green economy band. On most hills, it just digs in at 1,400rpm and stays there. When trundling through roundabouts in high range it will lug down to 1,000rpm and still recover.
When pulling away there's enough torque to skip gears in the low range: we only used the splitter in high range. Thanks to all that torque we found ourselves dropping down half a cog on hills where other trucks needed a full gear.
In general the GRS900 is well-matched to its engine. Like all synchro boxes it can be hard work when cold, but that's not its only shortcoming. When the current transmissions IP"
were unveiled in 1991, we assumed the traditional Scania game of "beat the range-change" was over. Not so: shift too quickly and you can still be left with a neutral.
It's difficult to believe the Topline cab is sitting on a four-point full-air suspension system. There's none of the wallowing and swaying found in other air-sprung cabs and virtually no body roll, Even during full-pressure brake testing from 64km/h, it was remarkably free of the violent bounce-back we've come to expect from high-roof tractors. The ride is firm but not harsh. Combined with the outstanding ZF steering box this underpins Scania's reputation for driveability.
As for the retarder, perhaps the best way to describe its effectiveness is to say that we wouldn't normally run down the long snaking descent from Carter Bar on the A68 between 30mph and 40mph without touching the service brakes.
That's exactly we did it with the retarderequipped Scania, and very safe it felt too. The service brakes also have plenty of bite; pity we can't say the same for its parking brake. While it clearly meets the C&U 12% gradient standard, it couldn't hold our fully loaded rig on the 20% (1-in-5) MIRA test hill.
That's unlikely to be a problem for general hauliers but it could be for tipper operators.
The mechanical difficulties in fitting frontspring park brakes to a tractor with two-bag rear air suspension are well-known (CM 21-27 October 1993).
We have no idea why Scania hasn't followed Volvo and Mercedes by adopting a four-bag system which allows spring parking brakes to be fitted on the front axle without any strain to the chassis.
We'll have to wait and see if the Series 4 does better. In the meantime, Scania offers a handbrake with an optional control position which puts air down the service line to the trailer's service brakes and allows you to hold, but not park, on a slope greater than 12%.
• CAB COMFORT
If truck manufacturers want to know how to get a driver into and out of a tractor cab safely they need look no further than the R143. Its broad, non-slip steps are perfectly placed for easy access.
Inside, the R-range cab may be a little dated compared with the likes of the FH Volvo and Iveco EuroStar, but its no-nonsense hardwearing trim of tweed and gray will not show the dirt and the black rubber mats in the footwells will be easy to keep clean.
What the Topline cab can't match is the storage and interior space that can be found in cabins like the Daf Space Cab. The underbunk chest is relatively shallow and there's no Renault Magnum-style wardrobe. The Topline's relatively low roof line also makes it hard for tall drivers to stand upright. Scania needs a full-height sleeper—roll on Series 4.
Cross-cab access isn't helped by the large centre console although its neat sliding lid will help keep loose items from rolling around and getting lost. There's also space in the headlining for odds and ends but (with apologies to the BBC's Points of View), why, oh why, oh why does Scania hide the radio up there?
That's the sort of detail that irritates drivers-but they'll love the Topline's Isri airsprung seat. It provided superb support throughout our three-day test, further complementing the Scania's commendable ride.
The curving dash puts everything within easy reach but does anyone really need all those switch positions?
No less than 16 of them were blanked off on our truck, which makes us wonder what extra electrics Swedish operators fit in their Se_anias.
Everything about the driving position is right, from the rake of the adjustable steering wheel to the spacing of the foot pedals. The R143-420's clutch pedal is slightly heavier to operate than many of its rivals but overall if you don't like driving this Scania you must be exceptionally hard to please.
• SUMMARY
By any yardstick, the R143-420 is the forgotten machine: of all the Scania tractors sold in the UK only 10% have the 14.2-litre vee-eight. And of that 10%, only 5% are 420hp models. More than 80% of buyers want the R143-450. Frankly, we're at a loss to see why because the 420hp model is likely to give the best fuel economy for minimal loss in journey time.
The 420 has other advantages over the EDC-equipped R143-500. Many operators who resent the way hi-tech electronics have taken maintenance out of their hands still want to buy a truck with a mechanicallycontrolled fuel injection system that can be serviced in-house.
Scanias never did come cheap and our comparison charts prove that the R143420 is no exception. But read the operator comments in our Used Truck Report on the R143 (CM 29 June-5 July)and you'll know why hauliers are prepared to part with their money.
This is probably the last R-range Scania tractor we'll test before the Series 4 arrives. Was it worth revisiting? Set against the likes of the Volvo FH12-420, with its all-new, electronically controlled, fuel-efficient DA12 straight-six, the R143-420 is beginning to show its age. But drive it right and there's no reason why you should lose out at the pumps.
We hope the new range will have lost some weight, and gained a bit more margin on the park brake. What Scania doesn't need to change is the R143's excellent ride and handling, first-class driveability and rock-solid reliability. Like many hauliers, we like them just the way they are.
E by Brian Weatherley