My 2022 JCW (CPO at 6k mikes) came with 19” Circuit Spokes with factory RFT and I found a set of 18” Thrill Spokes. I delivered the wheels to Discount Tires and had Pirelli P zero AS mounted and then brought them home. I went about changing the wheels/tires. First thing I noted was whoa, the 19” felt lighter than the 18”? I put them on the scale and sure enough the 19” with run flats weighed 47lbs and the 18” with regular tires 50.25lbs. According to tire rack the Goodyears RF weigh 28lbs (225x45x19) and the Pirellis (225x50x18) 24.75lbs. And a circuit spoke is 23lbs and thrill spoke 24.25lbs. So I cannot account for the measured weight of each set up. 19” *should* weigh 51lbs and the 18” 49lbs. Maybe the added air in the 18” made the difference 🤣

the other issue is they stuck the wheel weights on the outer side of the inner wheel barrel and the JCW brakes just touch the weights. So I have to remove the wheels and take them back to have the weights moved inwards. I all fairness the car was not there for them to know that issue. I’m assuming they can balance the wheels/tires putting the weights father inboard.

I realize that with the hp and torque of the JCW the increased corner weight with not be noted on the street, but intuitively the smaller wheel/tire combo are usually lighter. I will gain the extra sidewall for the comfort advantage (that was part of the goal in addition to protection for the crappy streets).