New to the site nimbus r27 138 / 500

do you lose much by having 18's? i know the tires are a little more expensive but does it compromise the ride at all???
I don't feel it does tbh but not managed a top speed test yet
She still sticks like glue and running 225 45 18 with no rubs or scrapes if anything my exhaust hasn't scraped a sleeping policeman for a while