I am a new and proud owner of a 2002 V6 Mustang, and I am looking into getting new rims for summer. Right now I have basic 16" stock tires, and I am a little lost when it comes to choosing the correct rim size. What my question is, is can I fit a 17" or 18" rim on a 16" tire? I've been told I must move up to a larger tire if I want the larger rim, but I've also read that it can be done without changing tire size - so now I am just mixed up. Do the tire size and wheel size have to be the same, or not? And what is the difference in performance/ride quality if I move up to a 17" or 18" tire/wheel?
Your rims and tires need to be the same size. If you want to put 17" or 18" rims on your car, you will be buying tires that have the same overall diameter, but have a larger "aspect ratio". That means that the inside of the tire will be larger to accomodate the wheel, but the amount of sidewall will be less. The upsides to this are the tire will still fit within the wheel well, and the final drive ratio will be very close to the original so your speedometer and odometer will still read correctly. The thinner tires and bigger wheels also look better. The downside is that the ride will suffer, since a thick sidewall gives you a bit of shock absorption. Going to the extreme- cars that have 20" or 22" wheels with 20 or 25 series tires ("rubber band tires")- will give you an extremely stiff ride and the wheels can be damaged by a good pothole. Another factor about going to larger wheels is the cost of the tires. If you do some pricing you'll see what I'm talking about. 18" tires are a lot more expensive than 16" and 17" tires, and there are fewer models of tires to choose from. To dress up your Mustang, I personally wouldn't go over 17" wheel size. They will look better, but your sidewall will still be thick enough to preserve your ride and protect your rims. One popular thing is to get the Bullitt style wheels from the GT, which are available for cheap on the internet with tires already on them. That's what I have, and I think I paid $550 for the set with nearly new tires- delivered!
Ok - great. You were very helpful! I have to ask though, right now my tires are 225 - 55 - 16s. What kind of an aspect ratio is reccommended if I were to buy 17s? I am confident enough to say that I would prefer to go with the 17s, and will stick to that idea after reading your post and doing some research. Since the aspect ratio on mine now is 55%, how much more of a percentage would be best to go up to? I don't want to have super "beefy" looking sidewalls, but I do want to preserve the ride quality like you said. Another thing is tire width, right now mine is 225, is that going to matter at all when purchasing new wheels? I guess I will do some more researching online. Thanks for your help!
The corresponding tire size for 17" wheels is 225/45-17. That will get you within 3 or 4% on the overall diameter for speedometer accuracy. The tread width you'll want to keep the same. Some people try to get a little wider tire (if a tire is even made in that size) for more traction, but you have to check to see if your wheel is wide enough to accept it. You also have to start checking clearance in the wheelwell- including full lock turns and compressed suspension. Generally the only people who do this are drag racers who need as much contact patch as possible (not a problem for our Sixes!). When you start shopping for wheels, Tire Rack - Your performance experts for tires and wheels has a neat tool that lets you visualize different brands and sizes of wheels on a side view of a Mustang to see how it will look!
Ok, again thank you for your help. I am looking at a set of Chrome 17 x 8 Bullitt style wheels on AmericanMuscle.com. On the site it shows the best fit tire size as 245/45/17 for either 17 x8s or 17 x9s. I also found out that if I were to put these on my mustang, that the speedometer would only be off by a tiny percentage that most likely wouldn't even be noticeable. These are the wheels I would like to go with, and I'm assuming I should buy the lug nuts to go with them to complete the look. Now I guess I have to decide on a tire. I was thinking about sumitomos.. but once again I don't know a whole hell of a lot about brands of tires either. I am assuming these are pretty popular performance tires as I've seen them on many mustang sites...?
