Easy one. They don't make a 110/90/19 Roadrider unless it's something new. Also, the standard rim would be too narrow to use it. Avon recommend a 2.5 inch rim for the 100/90 Roadrider. The 100s are a great tyre for the Commando. I've been through a bundle of them. When the rear is worn out, the front goes to the rear and the new one goes on the front.