Now that is strange. I was really expecting to see the aspect ratio of the tires (70) to be different and they are not.
Those tires should have the same overall height. I now have the same question as you have.
As the older tyre that came off was worn then it will have had less rubber on it and may not have fouled the fender and any new tyre with a full set of rubber would foul the fender
So perhaps the fender has moved in the time between the dunlop being new and the avon being fitted
If you loosen all the fender mount bolts and try to fine adjust the fender there should be a wee bit of movement and there may be enough play to move the fender away from the tyre
These are just my thoughts on what may have happened to create your current situation
Had someone say that for the tire to miss fender the fender mount holes need to be sightly oval to give room for adjustment, anyone hear of doing this?
The aspect ratio is the same but the Avon has a different profile than the Dunlop. When the tire is cold how much room is there from the tire to the fender? Like Fin suggested the fender will move a little without modifing the holes.
Yep, then it must be something that applies to the crown motorcycle tires have. That's crazy. If not by size, how can you shop or experiment with new tires?
I was thinking of trying a set of Avons next time around. Now I can't because I mail order my tires. They may not fit even though the numbers match. That's crazy if you ask me. That's like saying this 1/4 28 nut won't fit your 1/4 28 bolt because the manufacture put a special profile on the thread pitch.