13 March 1998

Impact is on performance

not the grass

AS THE final link between tractor and soil, tyres perform a crucial role that makes a big impact on performance.

At Causton Hall Farm, Little Cornard, Suffolk, Peter Schwind wanted to optimise traction and minimise compaction on his 155hp MF8130 and opted for Trelleborg Twin 414 tyres as the solution.

"Our main cultivation tractors were previously fitted with dual wheels which had to be removed for road work," says Mr Schwind. "For the MF8130 we decided to change the originals for a set of Trelleborg low ground pressure tyres which give us the largest possible soil contact area without having to change the wheels to travel on our narrow lanes."

The MF tractor is used forall ploughing, pressing, subsoiling and seed-bed cultivation on the farms 405ha (1000 acres) of cropped land on soils that range from sands to heavy clays. Minimising soil compaction is a priority during field operations.

Apart from spreading the weight of the tractor over a big contact area, the wide tyres – 700/65-38 rears, 600/55-30.8 fronts – have also proved effective at maintaining traction on steep gradients found on the farm, especially when hauling power-hungry implements like heavy press rings and the farms 5.2m (17ft) combination cultivator.

"We are probably close to the minimum horsepower needed to pull the combination cultivator satisfactorily on our soils and slopes," says Mr Schwind. "Without the big tyres, I doubt we would manage to get the job done and with such a good finish."

Low wear, fewer punctures and better grip is the pay-off for investing in wide, low-profile tyres, according to Wilts-based contractor Michael Abbott. And customers certainly appreciate their low ground pressure characteristics, he adds.

"These low profile radials are definitely the tyres to have," he says. "Since we started using the Michelin XM108, weve experienced less downtime and repair costs from punctures, they wear very well and they give plenty of traction. In some cases," he adds, "we have been able to keep working in conditions that have stopped machines on inferior tyres."

Contract services offered from the companys base at Dinton near Salisbury cover most agricultural field work, including grass and maize silage, specialist maize and fodder beet drilling, cultivations and drilling work for all combinable crops, and big square baling.

The tractor fleet includes three 120hp Fendt Farmer 312 tractors, a pair of 140hp Fendt Favorit 514C models and a 140hp Fendt Xylon 524. The rest of the fleet comprises a selection of 85-90hp Case-IH and Deutz-Fahr tractors.

All new tractors bought are now specified on Michelins low-profile XM108 radial traction tyres.

"As contractors we have a lot of road travel, especially during the silage season, and wear rates have been exceptional in our experience," says Mr Abbott. "Our first XM108s did more than 5000 hours with no punctures."

Silage-making operations centre on the Xylon 524 with a front-mounted Kemper forage harvester. It runs on 600/65R34 tyres up front, 650/65R38 rears, giving plenty of traction on damp, slippery grass and in the often wet, muddy conditions of a late forage maize harvest.

Similar tyres, albeit smaller sizes, are used on haulage tractors which take the brunt of road travel.

"Using bigger volume tyres also gives a much smoother ride, with less vibration or bumps and jolts feeding through to the driver," says Mr Abbott.

Other than that, the most important characteristics of the tyres, he believes, are the flat profile of the tread and the way the tyres can be run at relatively low inflation pressures.

"If the tyre is soft and supple, it can spread the load carried over a larger area," he points out. "That, together with the flat, broad tread means the tyre does little damage to field surfaces."

By Peter Hill

Fitting Trelleborg Twin 414 tyres all round has proved a practical and performance boosting move for Suffolk grower Peter Schwind. Using dual wheels meant their removal was required for road work.

Slow wear and a comfier ride are benefits of using wide low profile tyres – in this case Michelin XM108 – on grass haulage tractors, says Wilts-based contractor Michael Abbott. Fewer punctures have occurred too.