I'm fortunate to have both the 500x and 250L. (I prefer multiple lower priced bikes over a single more expensive one.) Unfortunately my unheated garage is 16° F at the moment so, while it would be great fun to do the dimensions up right by pulling things apart to measure and swap, the cold makes it impractical. The following are quick approximates. Please ask if you have a question on a particular part - tomorrow might be in the 20s. Both bikes are stock.. I tried to get measurements accurate to nearest 5mm but no guarantees. '15 CB500x Inner swing-arm 230 mm Outer width of stock rim at point where bead seat = 130 mm Outer width of stock tire (Pirelli Scorpion) = 155 mm '14 CRF250L Inner swing-arm varies from 210mm at furthest points aft where axle/sprocket are but tapers and narrows to 190mm as you move forward Outer width of stock rim at bead seat = 70 mm Outer width of tire (non-stock Kenda K270) = 125 mm Both bikes are engineered for roughly 70 - 80 mm of extra clearance between width of tire and width of swing-arm with the difference divided between the sprocket on the left and the brake and brake mount on the right. Love this thread. I'm impressed with the ingenuity here!