G-REX05,
Nobody seems to be answering your question so I’ll give it a try. I asked this same question a few weeks back at the shop.
My understanding is that a dyno calculates the torque (twisting power) against the rotations of the dyno rollers. If the tire is a larger diameter, it will turn the rollers on the dyno a bit faster, but there will be a bit less torque. The theory is that these factors should equal out to + or – 0.
So … the diameter of your tire alone should not change the output number.