Controlled experiment..
Need to set up 2 identical bikes. with only the tire different.
the tendency after doing the work, spending the Money,
is to consider the new thing better, to justify the work done and money spent.
even though there is no 'before' left to compare it with, anymore.
and there may actually be no real, significant difference ..
Like choosing 1 brand of guitar string over another , if they are Other wise made of same stuff.