Silage success lies in the preparation of your bale wrapper

Does your machinery need a clean? Are vital parts suffering from wear and tear?

These and many other questions can be resolved with an extremely straightforward programme of preparation that will give you an efficient and smooth-running season.

On paper, the process of bale-wrapping is a structured and simple one, but it can be considerably more costly and inefficient if the user ignores the various preparatory steps that must be taken at the start of the season.

Bale wrappers are no different from any other kind of machinery – a long period without use can encourage decay and increase the risk of important parts failing once back in use.

Farmers and contractors have it within their power to prevent this happening, both before and during the season. The seven pre-season checkpoints are:

Moving parts

Ensure all moving parts are free-rolling – pay particular attention to the Pre Stretch Unit (PSU), which can stiffen up or seize during periods of non-use.


Film overlap

Check for film overlap and correct stretch by wrapping a straw bale before the season starts.

a) Align centre of film reel with centre of bale to achieve 50% overlap.

b) Measure the amount the film narrows down as it is stretched on to the flat end of the bale (neck down). For 750mm film, between 580-610mm should be on the bale. With 500mm film this should be between 380mm and 410mm.

c) Measure correct percentage stretch by placing two vertical marks 10cm apart on the roll of film and then measuring the distance apart once on the bale. For 55% stretch it should measure 15.5cm and 17cm for 70% stretch.

d) Calibrate the correct number of turns to apply the minimum amount of film by counting the number of turns to completely cover the bale.

Then add one turn and double this number for a minimum of four layers. For all bales of 50% DM and above, add the one turn and then triple the total for six layers.

Table belts

Check table belts for wear and tear. Replace all, even if only one is damaged or worn. Badly aligned and worn belts will affect film overlap.




Examine PSU and turntable gearing for slop.



Inspect PSU rollers for any damage and thoroughly clean down with de-greaser.



Check PSU springs and replace if necessary. Weak springs, dirty or worn-out rollers will cause aquaplaning, film-tearing and uneven film application.





Ensure your equipment is maintained and serviced regularly in line with the manufacturer’s guidelines.


Further information

For advice on bale-wrapping preparation contact the Silotite team on 0800 0320 640 or visit where you can download the bpi.agri Contractor Handbook which contains the top 10 tips for successful bale-wrapping.



  • Bale sizes vary in both size and shape – extra turns may be necessary to achieve correct film application
  • If the above checks are carried out bale wrapping should run smoothly. It is however important to continue the good work through the season to prevent any problems

Four in-season checks:

  • Frequently clean down PSU Rollers with a de-greaser or white spirit
  • Regularly check for correct overlap of film and correct stretch and neck down
  • Routinely check the number of turns required to achieve correct film application – especially if different balers are being used – as sizes vary and in many cases not enough turns are being applied
  • Follow the film manufacturer’s instructions