Would replacing the run-flat tyres on my BMW X5 with normal tyres improve the ride quality? I recently bought a 2010 BMW X5 3.0D with 18in wheels and run-flat tyres. The test drive on dual-carriageway was fine. However, the ride on our local rural roads is atrocious; the car seems to transmit any imperfection in the road surface straight into the cabin.

It also seems prone to tramline at the least opportunity and requires a high level of concentration to keep it straight. I strongly suspect this could all be due to the run-flats and am considering replacing all four with normal tyres. I've checked with BMW, who tell me the warranty would not be affected by doing this. I understand the safety arguments and would be happy to carry a spare wheel, and jack etc.