Agricultural tractors operate in different soil and environmental conditions. Designing and adjusting the tractor parameters for high traction performance is the correct approach to obtain high efficiency in tractor operations. The aim of the study was addressed to measure and evaluate the traction performance of standard tractors for operating the tractor even in high demanding working conditions. A traction load measurement system was refined to measure tractor field data. Standardized trials on a concrete track for assessing the traction performance were executed. Traction performance, including drawbar pull, traction force, travel reduction and net traction ratio were evaluated. Two tractors pertaining to the same family type, designed with the main features equivalent but with different power engine, were compared. To analyze traction performance three parameters were considered, tractor mass, tyre pressure, engine power, for a total of six different operating conditions. The results measured at forward speeds lower than 6 km/h denoted that the net traction ratio increased at the lower tyre pressure in reason of the drawbar pull increase. The mass increase affected the drawbar pull resulting in an increase in traction force across the entire speed range. Comparing the low-power tractor to the high-power one at the low forward speeds, the drawbar pull was similar in the tested configurations, while increasing the forward speed above 4 km/h, the tractor with higher power output showed a significant increase in pulling force and consequently in traction ratio. The travel reduction (slip) was affected mainly by the tractor power. The slip started to have a reduction in between 4 and 5 km/h for the 66 kW and 86 kW agricultural tractors respectively. The traction performance of the tractor was affected by a proper adjustment of the tractor parameters and the results of the evaluation can serve as a guide in tractor design and use.