Originally Posted by Tony B
The same size tyres are used ZCP v non-ZCP.
As the wheels are wider front and rear this means the tyre sidewall is a different shape (the tyres are stretched out more) which makes them feel stiffer - you will notice a slight deterioration in low speed ride quality because of this.
The change in sidewall profile also changes the feel of the steering and the responsiveness to steering inputs.
I should mention I put my 18s (219Ms) on and that's what I'm referring to. Not with ZCP wheels on actually. What you say in that regard makes sense.