Do I need to weight or ballast my tractor tyres with water?

Ballasting consists of increasing the weight of your tractor to improve tyre grip or lower its centre of gravity when working with heavy tools or high traction.
But what's the best form of ballasting?

ballasting of the agricultural tractorToo much weight at the front could break the front axle assembly, whilst not enough weight can lead to excessive slip and slow down your work, as well as quickly wearing down your tyres.

As it turns out, ballasting your tractor tyres with water is still the simplest and most cost-effective way to ballast your tractor without mechanical risks. But how should you go about ballasting your tractor tyres with water?

 

Ballasting my tractor is essential if it's not heavy enough for my tools

In order to use heavy tools or have a high tractive force, when ploughing for example, you need to increase the weight of your tractor. A vehicle's traction capacity is directly correlated to its weight. Ballasting helps improve your tool's grip.

This reduces slip, which means less soil damage, more working efficiency (shorter working times), and longer-lasting tractor tyres (less lug wear).

This is therefore a particularly useful solution for jobs that require a lot of traction, especially when the ground is very wet and you're working with a high torque (ploughing), because the tractor needs to move forward without slip to avoid smoothing out the ground and compacting the soil.

 

How do I find the correct ballast and avoid excessive tyre slip?

You can detect excessive slip by observing the tracks left by your tyres on the soil. If the shape of the lugs is not clearly defined, or much thicker than the actual size of the lugs, it means there is too much slip.

Accumulation of earth between the tyre lugs is also a sign of high slip, resulting in a substantial loss of tractive force and therefore additional fuel consumption and premature tyre wear.

You therefore need to calculate the slip ratio to determine whether or not your tractor needs to be ballasted. To do this, drive your tractor over a given distance (100 metres, for instance) while someone else counts the number of times the wheel rotates over this distance. Next, calculate the theoretical number of wheel rotations for that distance (distance travelled / wheel circumference). Finally, use the following formula to obtain the slip ratio:

formula for calculating the slip rate

Ideally, this ratio should be between 12 and 15%.

Ballasting allows you to reduce your slip ratio by improving your tractor's grip and stability. This can be especially useful if your plot is on a slope.

 

When should I use metal weights for ballasting?

The use of metal ballasts is recommended if you wish to modify the load distribution between the front and rear of your tractor, which is more difficult to achieve with water ballasting.

The use of metal ballasts is also more flexible, because you can adjust the number used based on the desired weight. However, installation is a very laborious procedure because it requires the use of lifting equipment due to the sheer weight of the ballasts.

To guarantee precision when adding weights, you should use a weighing device for each axle and check the tyre's maximum load index as recommended by the manufacturer.

Warning: some very heavy tools might still be too much for your tractor, even when ballasted. If this is the case, you may have to mount twin tyres to bear the weight and better distribute the tractive force.

RULES FOR BALLASTING WITH METAL WEIGHTS

If your tractor has to bear or pull a light load, most of its weight must be supported by the rear axle assembly. On the other hand, if the load is heavy, the weight must be distributed equally between the front and rear axle assemblies.

Weight distribution between front and rear axle ASSEMBLY (%)
  LIGHT LOAD MEDIUM LOAD HEAVY LOAD
  Front axle Rear axle Front axle Rear axle Front axle Rear axle
2WD 25% 75% 30% 70% 35% 65%
4WD 35% 65% 35% 65% 40% 60%

The metal weights must be placed as low on the machine as possible to lower its centre of gravity and stabilise it.

 

When you should use water to ballast your tractor tyres

Water air valve for tractor tyreWater ballasting is useful because it's cheaper and easier than ballasting with weights.
Ballasting with water must be used the same as permanent ballasting if your tractor is too light for the work you want to do, but it does not allow you to rebalance the weight between the front and rear of your tractor.

First of all, you must ensure that your tyres are compatible with water ballasting (check the information provided by the manufacturer). Most importantly, they must be equipped with an air/water valve.

How to water ballast your agricultural tyres:

water ballast agricultural tyres
  • Place the tyre vertically and decrease the pressure to 0.5 bar.
  • Position the tyre valve pointing up. This allows the air to escape as you fill it.
  • Fill the tyre with a water and antifreeze mixture up to ¾ of its height, or until it's level with the valve. Make sure you use the right amount of antifreeze to avoid having problems in the winter.
  • Adjust the pressure of the remaining volume of air.

As there is now less air inside the tyre, you will have to check the pressure more frequently. In addition, this will reduce shock absorption and comfort (which can be compensated for by the suspension) on roads in particular and will reduce your tractor's speed.

Before you ballast your tyres, always refer to the manufacturer's instructions on the filling procedure (see the filling volume table below):

TYRE DIMENSIONS LITERS (kg)   TYRE DIMENSIONS LITERS (kg)
200/70 R 16 35   380/85 R 30 220
240/70 R 16 40   420/70 R 30 225
260/70 R 16 45   420/85 R 30 270
265/70 R 16 45   460/85 R 30 340
285/80 R 16 60   480/70 R 30 275
425/55 R 17 95   495/70 R 30 300
505/50 R 17 145   540/65 R 30 330
280/70 R 18  55   600/65 R 30 440
325/70 R 18  82   600/70 R 30 490
355/60 R 18  102   710/60 R 30 600
365/70 R 18  105   270/80 R 32 100
275/80 R 20  65   300/85 R 32 140
280/70 R 20  60   320/90 R 32 150
280/85 R 20  65   650/75 R 32 570
300/70 R 20  70   680/85 R 32 810
320/70 R 20  80   800/65 R 32 740
335/80 R 20  105   900/60 R 32 1030
360/70 R 20  105   380/85 R 34 240
365/80 R 20  135   420/85 R 34 290
375/70 R 20  120   460/85 R 34 380
380/70 R 20  120   480/70 R 34 310
405/70 R 20  140   480/75 R 34 335
425/75 R 20  150   520/70 R 34 355
280/85 R 24  85   540/65 R 34 360
320/70 R 24  100   600/65 R 34 465
320/85 R 24  115   340/85 R 38 215
340/85 R 24  140   420/85 R 38 320
360/70 R 24  125   460/85 R 38 420
380/70 R 24  145   480/70 R 38 340
380/75 R 24  155   520/70 R 38 395
380/85 R 24  185   520/75 R 38 420
405/70 R 24  155   520/85 R 38 530
420/70 R 24  170   540/65 R 38 420
420/85 R 24  240   580/70 R 38 550
440/65 R 24  185   580/75 R 38 590
445/70 R 24  205   600/65 R 38 500
480/65 R 24  210   650/65 R 38 630
480/70 R 24  225   650/85 R 38 900
480/75 R 24  240   710/70 R 38 800
495/70 R 24  260   900/60 R 38 1200
500/85 R 24  310   300/95 R 42 185
540/65 R 24  300   460/85 R 42 460
280/85 R 28  100   520/85 R 42 580
320/85 R 28  130   650/65 R 42 650
340/85 R 28  160   380/85 R 46 330
380/70 R 28  165   460/85 R 46 500
380/85 R 28  205   520/85 R 46 620
420/70 R 28  200   270/95 R 48 150
420/75 R 28  220   340/85 R 48 230
420/85 R 28  250  
440/65 R 28  200  
480/65 R 28  250  
480/70 R 28  260  
480/75 R 28  280  
540/65 R 28  315  
600/65 R 28  400  

 

To check your ballasting, look at the soil footprint of your tyre afterwards.

empreinte-pneu-de-tracteur-sous-lestage.jpgIf the footprint is not clearly defined, it means there is too much slip and your tractor has still not been ballasted enough.

 

empreinte-pneu-de-tracteur-lestage-adapt.jpg

If the footprint is too deep, there is very little slip but too much compaction.

 

empreinte-pneu-de-tracteur-lestage-excessif.jpg

Ballasting is adequate when you see well-defined edges on the tyre footprint.

 

 

The right ballast will enable you to get the best performance out of your tractor tyres, the tractor itself and the tools used, while still preserving the quality of your soil.

 


To learn more and boost your farm's profits, Bridgestone-Agriculture is offering you a free, detailed eBook that explains the essential role your agricultural tyres play in your productivity.

Download eBook: Increase the profitability of your operation

The information contained in this publication is for guidance purpose only. Whilst every effort has been taken in its production, no responsibility can be accepted for any loss or damage arising from any kind of undetected technical or commercial error contained in this content. Any data supplied in this publication is subject to possible revision following the date of publication. Due to the constant advance of tyre technology, the contents of this publication are subject to change without notice.