hi all im after some slicks my car is currently on 225 40 18 tyre size what is the nearest equivalent to that is it 210 650 18 or is it 240 650 18 thanks in advance

 

as a tyre fitter ive never heard of the last 2 tyre sizes u can have 215 40 18 to go down or 235 40 18 to up

 

Welcome to race world.
First figure is the width, so depends you may struggle with the 240 as it'll probably be nearer 245 width! But the 210mm would be going narrower
650mm is the overall diameter, your std tyres are 637mm, so they are both slightly larger.