The objective of the paper was to analyse traction properties of tyres on the forest subgrade of varied moisture and variable strength parameters. The research was carried out on the natural ground forest road at three varied moistures of subgrade: 10.5, 13.4 and 19.2%. Traction research was carried out with the use of a specialist stand, where the following tyres were investigated: 5.00-10 (on a single wheel and twin wheels) and 18x9.50-8 in the version without a chain and with an anti-skid chain. The investigations, which were carried out, proved that traction properties strongly depend on the condition of the subgrade. The increase of the subgrade moisture influences deterioration of traction properties of the researched tyres. It was found out that twinning wheels and using anti-skid chains result in the improvement of traction properties and cause the increase of shearing participation in the generated traction force. Loading wheels caused the increase of traction forces, whereas it did not influenced significantly the value of traction efficiency.