What is the maximum
load my trailer tyres can bear?

Trailer tyres are pushed to their limit during a harvest – they go from being fully loaded to empty in the space of a few hours, they switch from fields to roads several times a day, and farmers typically prefer to increase the load rather than make an extra trip.
But just how far can you push them? How much can your trailer tyres bear, and what can you do to prevent problems at a time when everything has to be done as quickly as possible to save time?

Loading of trailer tyresDuring harvest time, transportation is already considered as the black mark slowing down your harvester's capacity, so just imagine the effect of a punctured trailer tyre due to overloading, an undetected weakness or the intensive use of a tyre that's too old.

 

Adapt your use to the load and speed indices of your tyres

Load index and speedThe load index is written on your tyres in the form of a number, usually between 100 and 200, corresponding to the acceptable load for the tyre at a given pressure.

The speed index is a letter that corresponds to the usage speed of the tyre. You will need to calculate these indices to make sure you choose the most suitable tyres for your intended use.

To do this, refer to the load and speed index tables provided by the manufacturer.

The technical data you should pay attention to on your trailer tyres

» Load index table
I.C. kg I.C. kg I.C. kg I.C. kg I.C. kg
60 250 61 257 62 265 63 272 64 280
65 290 66 300 67 307 68 315 69 325
70 335 71 345 72 355 73 365 74 375
75 387 76 400 77 412 78 425 79 437
80 450 81 462 82 475 83 487 84 500
85 515 86 530 87 545 88 560 89 580
90 600 91 615 92 630 93 650 94 670
95 690 96 710 97 730 98 750 99 775
100 800 101 825 102 850 103 875 104 900
105 925 106 950 107 975 108 1 000 109 1 030
110 1060 111 1 090 112 1 120 113 1 150 114 1 180
115 1215 116 1 250 117 1 285 118 1 320 119 1 360
120 1 400 121 1 450 122 1 500 123 1 550 124 1 600
125 1,650 126 1,700 127 1,750 128 1,800 129 1,850
130 1,900 131 1,950 132 2,000 133 2,060 134 2,120
135 2,180 136 2,240 137 2,300 138 2,360 139 2,430
140 2,500 141 2,575 142 2,650 143 2,725 144 2,800
145 2,900 146 3,000 147 3,;075 148 3,150 149 3,250
150 3,350 151 3,450 152 3,550 153 3,650 154 3,750
155 3,875 156 4,000 157 4,125 158 4,250 159 4,375
160 4,;500 161 4,625 162 4,750 163 4,875 164 5,000
165 5,;150 166 5,300 167 5,450 168 5,600 169 5,800
170 6,000 171 6,150 172 6,300 173 6,500 174 6,700
175 6,900 176 7,100 177 7,300 178 7,500 179 7,750
180 8,000 181 8,250 182 8,500 183 8,750 184 9,000
185 9,250 186 9,500 187 9,750 188 10,000 189 10,300
» Speed index table
SPEED CODE SPEED (km/h)   SPEED CODE SPEED (km/h)
A1 5   B 50
A2 10   C 60
A3 15   D 65
A4 20   E 70
A5 25   F 80
A6 30   G 90
A7 35      
A8 40      

The speed code is the potential speed for a load matching the load index, under the usage conditions specified by the manufacturer.

In all cases, for optimal use of your tyres remember to adapt the pressure in accordance with the manufacturer's data, and check it regularly.

 

Respect load and speed regulations

» SPEED

Your tyres are capable of withstanding high speeds, provided you have respected the corresponding load (see table above), and some trailers are approved for high speeds. However, the regulations stipulate a maximum speed for tractors alone, which is very different to the speed for a hitched vehicle.

The authorised speed limit for a tractor with trailer is only 25 km/h, regardless of whether or not the trailer is loaded.

» LOAD

The permissible gross weight on your tractor's registration document tells you the total authorised weight when coupled (weight of the tractor + trailer + load).

The loading point of reference for semi-mounted trailers is limited to 16 tonnes for single axle, 29 tonnes for twin axle and 32 tonnes for triple axle.

Load limits are very easily reached

Single-axle trailers are only permitted a load of 16 t, which is reached when the trailer is loaded normally. For high-power 200 hp tractors with a triple-axle trailer, it is very easy to exceed the authorised limit of 40 tonnes on the road. And don't forget, the fine for overloading your trailer can be as much as €1500.

 

For heavier loads, increase the size of your tyres

To reduce the impact of driving your trailers on your land, choose wide low-pressure tyres. The width of the tyre helps distribute heavy loads, and the large volume of air contained in the tyre enables you to increase the permissible load without increasing the pressure. Since the pressure exerted on the ground is correlated with the tyre pressure, a low pressure will limit compaction, even with a trailer full of harvested grain.

 


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.