Originally Posted by
Wilfred Laurier
you could also try to mount those tires with a wider rim
this might bring the outer diameter down a bit
or it might not
just a thought
The difference will be miniscule, and replacing rims isn't a cheap option.
In any case, widening the rim will increase the overall circumference of the cross section which would increase not decrease the diameter. A simpler option is to carefully shop tires with the biggest actual size that clears, regardless of nominal size. But that seems to be where the OP is already.