Donnelly Sports GJT Tire - 29 x 2.5 Tubeless Folding BlackDonnelly Sports GJT Tire 29 x 2. 5 Tubeless Folding Black. The GJT is a large knobbed trail tire ready for the big fast and rough trails. A row of big center knobs helps the tire attack the trail keeping good traction and braking The alternating center and shoulder knobs make for a tire to be rolled easily from the center to the outside Supportive side knobs allow you to roll the tire to the edge with confidence in the corners Sidewall protection lets