Question: what is jj in rims?
Answer: J is the most common shape of a rim flange on passenger cars. The letter B appears at the smallest wheel sizes primarily for older car models, with diameters 12″ and 13″ and rim widths up to 5.0″. J rim contour has 17.5 mm high rim flange but B has only a 14 mm. JJ designation is most common on 4x4 and SUV vehicles.