BMW

Can i put some 20" rims on my 2001 bmw 530i or should i go with 18" what are the problems that may arise if any?

As you increase the size of your rims, you will need to decrease the height of your tires. the tires you use will also have harder side walls to support the weight of the car and stresses of the driving conditions.this has 2 effects:- you can corner a lot sharper due to decreased sidewall flex.- you will have a much bumpier ride because your tires now cannot absorb as much shock as before due to the hard sidewalls (kiss the nice refined 5-series ride nicebye). for the same reason, you can also bend your rims a lot easier if you hit a pothole.lower profile tires also have straighter sidewalls as opposed to slightly bulging sidewalls, this reduces the protection your rim will have should you accidentally brush against the curb.in the end of the day, you are upgrading your rims most likely for looks, but you will have to drive carefully (while having a harsh ride) to maintain that looks... for your 530i, the most i would go for would be 17" or 18".