Generally I recommend going as wide as possible so if your frame has clearance go for a wider tire, You will thank me and the person who sold you the tires. Wider is better up to a point. Certain bikes are for racing or are quite old school and have limited tire clearance (Clarence) but generally 23-25 isn't so bad and will likely fit unless you have a bike designed purely for racing that is older. A lot of Keirin bikes have almost no clearance nor do they need it for track racing where everything must be the same.