Smaller wheels

I have a 2013 Jeep Grand Cherokee Limited with 20in wheels. I am looking to get a softer ride from the car, so would it be possible to replace the wheels with 18in versions? Ray Bradford

According to the data I have, a set of 17in wheels should be available for your vehicle – the bolt pattern of 5 x 127 is standard across the Jeep wheels. The tyre you have at the moment should be 295/45 x 20, so a tyre size of 245/70 x 17 should give you the same outside diameter, meaning the speedo operation will still be within the tolerance limits. Alternatively, a wheel and tyre size of 245/60 x 18 will give similar results and will cause the speedometer to read around 1% higher than the actual speed.

Either of the higher profile tyres will give you a much softer ride, but you will need to check the clearance between the rim and the brake caliper as the rim of either size will be 8mm closer to the hub.