measure the distance from the centre of a wheel stud to the centre of the next wheel stud (pitch centre diameter PCD ) you need this size ,usually 100 mm, plus the width, usually 5 1/2" or they wont fit. Look on car spares website for spare wheels ,or approach your local new car sales office and see if they have any steel wheels for sale from vehicles when they have fitted new alloy wheels ,or a local tyre fitter who has swopped tyres onto new alloy wheels .