10 May 1996


Belts on round balers cause fewer headaches than they used to but can still be a source of downtime. Peter Hill sought some timely advice on how to get the best from them

UNTIL balers with steel rollers or slats came along, belts were used exclusively on round balers, providing a ready means of making a bale of almost any diameter within the overall size of the machine.

This arrangement is still used by John Deere on its 570, 580 and 590 balers and on the Welger RP400. Greenland has two separate sets of belts on its RV156 and RV186 machines and New Holland uses belts in conjunction with steel rollers on the 644 and 654 roll balers.

"Apart from these newer models there are still plenty of older belt-type round balers still in use for which the original specification belts are still available," says Paul Bennett of Benson Beltings. "The length, width and arrangement of belts differs quite a lot from one machine to another, so it is important to specify the right replacement belts for the particular baler. In general, I think it is better to stick with the manufacturers original configuration and belt specification rather than trying to change it."

Significant advances

But it is worth looking into the opportunities for using modern belts on older balers, because significant advances have been made. The belts themselves are stronger and so are the fasteners, and different surface textures have been developed to achieve consistent performance with contrasting materials.

This is a difficult area given that the same baler may be used for wet, heavy grass and dry, brittle straw. A belt with too little surface grip may have difficulty getting some materials to start rolling into a bale, while those with too much grip can pull loose material out of the bale, leaving it to wrap around rollers. This can also get net wrap systems into a tangle.

Stones and other debris permitting, good operator technique and preventive maintenance are the keys to getting a long service life out of round baler belts, suggests Tim Baker of Greenland UK. Improvements in design have increased the strength and characteristics of these components but the way an operator uses and looks after his baler still has a significant influence how long they last.

"The move to stronger belts and, more particularly, stronger fasteners, has greatly reduced the problems round baler users have with belts and has increased their useful service life," says Mr Baker. "But some operators still get far fewer bales out of a set of belts than others."

The principle factor, he reckons, is the way the chamber is filled during the initial bale formation phase and how often belt tracking is checked.

"Operators know that feeding the swath evenly into the chamber leads to better shaped bales but few realise the difference it can make to belt life," insists Mr Baker. "Too much grass in one side puts uneven tension across each belt, causing it to twist. If that is done often enough the belt stretches unevenly and will not track properly."

Something to watch

This is particularly crucial during the early stages of bale formation, as even a modest lump of grass going into the chamber can make a big difference to the diameter of the fledgling bale.

"It is not that operators have to achieve a perfectly even feed of grass into the chamber but it is something to watch," Mr Baker suggests.

So is belt tracking, which should be checked regularly, he advises. Belts running too far out of true end up rubbing against the side of the baler or the metal belt dividers and this abrasion will soon damage fasteners and wear away one side of the belt.

"Tracking is easily re-set using an adjustable roller and, if you get one belt going the opposite way to the others, try turning it round to solve the problem," he says.

Regular inspection of belt joints is the best way to avoid awkward and time-consuming breakages in the field, argues Bensons Paul Bennett.

"Belts take a lot of hammering, particularly in silage, and are constantly relaxed then put under extreme tension with a lot of stress imposed on the area around the fastenings," he points out. "It makes sense to check this area, as well as the connecting pin, for wear or damage in the hope of seeing signs of failure before the joint comes apart in the field."

Fasteners are stronger now than they used to be but New Holland decided on a different approach with its 640/650 hybrid belt and roller balers by using endless rather than joined belts.


"It is a true endless belt, not one where the ends are overlapped and glued," emphasises Derek Gardner of New Holland. "It eliminates the one weakness of all other belt balers and we reckon the belts are as much as two-and-a-half times as strong as a joined belt as a result."

The downside is that if a belt does need replacing the task is rather more complex than feeding in a conventional belt and joining it.

"If a belt fails in the field, which is pretty rare, then our advice would be to simply cut and join it for expediency," says Mr Gardner. "But two men competent with a set of spanners should be able to replace a set of endless belts in about half a day." &#42

Baler belts are stronger than they used to be, as are fasteners. They are also better able to cope with differing conditions and different crops.