Na osnovi poznavanja dimenzijskih značajki skidera s vitlom (osnovne dimenzije, masa vozila, položaj točke težišta), razvijen je model procjene kretnosti skidera za privlačenje drva uz nagib terena na siguran, djelotvoran i okolišno prihvatljiv način. Model je zasnovan na graničnom nagibu kretnosti skidera temeljem vučne značajke vozila, koji povezuje dva istraživačka pristupa, 1) vozilo – teren (raspodjela sila ovisno nagibu i vučenom teretu) te 2) kotač – tlo (procjena vučnih značajki skidera temeljem indeksa kotača), uz poštivanje niza ograničenja proisteklih iz prethodnih istraživanja: i) rasterećenja prednje osovine vozila, ii) preopterećenja stražnje osovine vozila, iii) najmanje uzdužne stabilnosti skidera, iv) najmanje nosivosti šumskog tla te v) dopuštenog opterećenja pneumatika. Rezultati simulacijskog modeliranja procjene kretnosti skidera s vitlom Ecotrac 55V opremljenoga pneumaticima 12.4-24 pri privlačenju drva uz nagib terena, značajno se razlikuju s obzirom na uvjete nosivosti podloge te masu vučenih tereta. Kod manjih tereta, mase do 1 tone, kretnost skidera određuju kriteriji/ograničenja graničnoga nagiba kretnosti vozila (vučna značajka) i okolišne pogodnosti (najmanja nosivost podloge). Porastom težine tereta, osim nosivosti šumskog tla, odlučujući ograničavajući čimbenik kretnosti postaje odnos opterećenja prednje i stražnje osovine vozila (>1 : 3,5), koji ograničava kretnost skidera na terene nagiba <33 % kod tereta od 1,5 tone, tj. <20 % kod tereta od 2 tone. Kod tereta od 2,5 tone, na kretnost skidera, utječu kriteriji najvećeg dopuštenog opterećenja stražnje osovine skidera na nagibima <7 %. Based on the dimensional characteristics of the cable skidder (dimensions, weight, position of the center of gravity), a model was developed for estimating the mobility of the skidder during timber extraction (skidding) uphill in a safe, efficient and environmentally sound way. The model is based on the limiting slope of skidders’ mobility depending on the traction performance of the vehicle, which connects two research approaches, 1) vehicle – terrain (distribution of forces depending on the slope and load) and 2) wheel – soil (traction performance based on wheel numeric). The model is in compliance with a number of restrictions arising from previous research: i) unloading the front axle of the vehicle, ii) overloading the rear axle of the vehicle, iii) minimum longitudinal stability of the skidder, iv) minimal soil bearing capacity and v) allowed tyre load capacity. The results of the mobility of the cable skidder Ecotrac 55V equipped with 12.4-24 tires during skidding timber uphill, differ significantly with regard to the load-bearing capacity and the load size. For smaller loads, weighing up to 1 ton, the mobility of the skidder is determined by the criteria/limits of the skidder gradeability (traction performance) and environmental benefits (minimum load-bearing capacity). As the weight of the load increases, apart from the load-bearing capacity, the decisive limiting factor of mobility becomes the load ratio of the front and rear axles of the vehicle (> 1: 3.5), which limits the mobility of the skidder on slopes <33% for loads of 1.5 tons, <20% for 2 tons. At a load of 2.5 tons, the mobility of the skidder is affected by the criteria of the maximum allowable load of the rear axle of the skidder on slopes <7%.