100/90-19 may not fit the early front fender that the 68 Commando used. You may have to go to a narrower tire for the front. It fits no problem on the rear. Wider rims are better for the footprint. I use 2.5" rims (WM4) on my 74 850. These tires fit both front and back on this year bike but the front fender is wider than the earlier models.
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