I laced up new rims the same width as a 550 for my 400F, 1.85x18 and 2.15x18. These are also the same size as my RD400F which I have BS BT45s. I can find the front 90/90/18 but can't find a 100/80/18 rear (or 100/90/18). Looking for reccomendations for tires, I like the BT45s but all I can find in a 100/90 rear is Avon AM26. Does anyone know where I can get a BT45 in 100/90/18 rear? What do you think would work best on my CB400F, and what size? Is a 110 rear too big for this bike, or are the Avons a better choice? Thanks in advance.