Oh my, this could explain things. I have Avon AM26s on my Shadow, my 1966 Triumph Trophy 650, and my 1972 Triumph Daytona 500. I like the way the bikes feel and handle with these. Late last year I started to recommission another '70s Triumph Daytona 500 I have had for quite some time. I went to buy AM26s in 3.25x19 for the front and 4.00x18 for the rear, none were to be had anywhere. I even went looking for the close metric equivalents, but couldn't find any in stock. I finally settled for a set of Michelin Pilot Activs, to keep moving forward. With a few more Triumphs in need of new rubber this could be a bit of a problem.