fourthmeal
Banned
When it comes to optimum wheel width to tire cross section width, really the tire manufacturer's specs will tell you what is allowed and what is recommended. For performance-sake, I've always said that it is better for the wheel to be wider then the tire then the other way around...within the reasonable limits of both the tire, the wheel, and the car itself. Meaning, if you put a 235/40-18 tire on a 8" rim, that's all well and good, but an 8.5" rim would be slightly better if the wheel didn't weigh more. Why? Because the tire is shaped better for handling with a slightly wider wheel. Its a case of geometry, really. A good way to prove this is to look at Porsche or other high-end cars and their stock tire size compared with their wheel size.
At any rate, the most important thing is to pick a tire size that fits the car, the wheel, and the situation you intend to put the car in. For our car, it comes with 214/45-18's stock in MS3 form, and fits our 18x7 wheels. If you want to go wider, you also will end up taller unless you drop your sidewall profile down to 40, so that makes going to a 225/40 or 225/45 incorrect (though it still works, it is indeed going to throw off your speedometer.) But a 235/40 OR a 245-40 are much, much closer to stock height and it will work far better. The only problem then is you need a wider wheel then the stock 7"! So, to accommodate this, the search begins for 18x8 or even wider wheels, but our offset requirements are very specific at these sizes. As jp4130 proved, an 8.5" wheel is possible if you select the right offset CAREFULLY. Now with a wheel that wide (or down to 8"), you can easily run a 235/40-18 or possibly maybe a 245/40-18. Your next enemy is the fender edges, because you are now pushing the limit of the available space in the fender well. A 235/40-18 is about the limit it seems, but I suppose you could roll the rear fender lip a bit and get a 245/40-18 in there relatively easily.
Once again, jp great job. That took balls to try, and I commend you for it. The tolerances you've shown are amazingly tight, yet it works. Its going to be exciting to find out if you can 245/40-18's on that wheel or if that is just too much. It depends on the tire, too! I've noticed each brand of tire has a slightly different shape to its tread style, and the smallest of changes here could make or break it for you. IMO, the 235/40-18 gives you the best of all worlds, plus you stuck WEDSPORT wheels on your ride and that's worth points alone.
At any rate, the most important thing is to pick a tire size that fits the car, the wheel, and the situation you intend to put the car in. For our car, it comes with 214/45-18's stock in MS3 form, and fits our 18x7 wheels. If you want to go wider, you also will end up taller unless you drop your sidewall profile down to 40, so that makes going to a 225/40 or 225/45 incorrect (though it still works, it is indeed going to throw off your speedometer.) But a 235/40 OR a 245-40 are much, much closer to stock height and it will work far better. The only problem then is you need a wider wheel then the stock 7"! So, to accommodate this, the search begins for 18x8 or even wider wheels, but our offset requirements are very specific at these sizes. As jp4130 proved, an 8.5" wheel is possible if you select the right offset CAREFULLY. Now with a wheel that wide (or down to 8"), you can easily run a 235/40-18 or possibly maybe a 245/40-18. Your next enemy is the fender edges, because you are now pushing the limit of the available space in the fender well. A 235/40-18 is about the limit it seems, but I suppose you could roll the rear fender lip a bit and get a 245/40-18 in there relatively easily.
Once again, jp great job. That took balls to try, and I commend you for it. The tolerances you've shown are amazingly tight, yet it works. Its going to be exciting to find out if you can 245/40-18's on that wheel or if that is just too much. It depends on the tire, too! I've noticed each brand of tire has a slightly different shape to its tread style, and the smallest of changes here could make or break it for you. IMO, the 235/40-18 gives you the best of all worlds, plus you stuck WEDSPORT wheels on your ride and that's worth points alone.
