as others have said if there markings on the sidewalls on the outside of the tyre then ask any tyre place to get it checked out by a proper tyre place. and remember don't fall for the first tyre place as they can usually trap you by increasing the price of a tyre. shop around, have a look on the internet print out some quotes and usually some places like national tyres and kwik fit can match them over the counter as long as you have a printed quote for like for like tyre