Confused on tire width v height for older skinny wheels.

Confused as sh..........

XS650, minimalist cafe style bike.
Front Wheel: 1.85" x 19"
Rear Wheel: 2.15" x 18"

I have the charts, I have read the forums, I have reached out to Avon tires and I'm still confused.

Looking at the AM26 tires, If I go by matching outer diameters, then 3.25-19 (26.1" tall) front and 110/90-18 (26.1" tall) both of which are on the fitment list for my wheels but 1 step below the optimal middle measurement. In this case I gain a tall sidewall which in theory diminishes handling.

Alternatively, there is a 90/90-19 (25.5" tall) front and 110/80-18 (25.2" tall) rear that lowers the sidewall a bit at the expense of 0.2" in rear width which shouldn't matter. Otherwise all else is equal.

I'm leaning toward the 90/90 & 110/80. I've heard this might be the recommended size for me from another member. Anyone have any insight to share?

Thanks.

Yep, 90/90 front and 110/80 rear definitely won't hurt anything unless you have previous experience on the race track with it. When I had the exact same wheel sizes I ran a 100/90 front and 110/90 rear with no issues.