I ordered my Kosei K1 16" X 7.5" racing wheels about 10 days ago. Along with the wheels, I ordered a set of Kuhmo Supra 712 in the recommended 215/55s according to the TireRack. After thinking about for a while and since I've still got time (now the wheels won't be in from Japan till 11/14) it's occured to me that these tires might be too short. The 97+ Maxima SE comes with 215/55s stock, BUT that's on a 16X6.5 rim. The Kosei rim is 7.5" wide. I fear the tire is gonna be strecthed out to far to accompany the width of the rim therefore making the tire shorter overall making my fendergaps look bigger and making my speedometer off. I wouldn't worry if the K1 was 7" wide, but 7.5" vs 6.5" is pretty drastic. Should I change my order and go with 225/50 Kumhos instead?

Dave

 

I would stick with the 215/55s, as it will maintain the original total diameter. The alternative will reduce the diameter by 2%, which will not be enough to have any impact on the speedometer, odometer or fitment...

 

Why not run a 225/50-16 tire? I shouldn't be that much smaller than stock tires but it would give you shorter gearing. Look at it this way if you get radared by a cop your speed will be less than you think .

 

According the Kumho website, the 215/55R16 is 25.1" in diameter where as the 225/50R16 is 24.9" in diameter. I just measured my 235/45R17s and they are 24.8" in diameter. I'm gonna measure my stock 15s tonight and compare numbers. Theoretically, the sidewall ratio is a percentage directly related to the section contact patch of the tire. So a 225/50 means the sidewall would be 50% of the tires contact patch.

I just fear that the wide 7.5" rim will reduce the sidewall of a 215/55 too much. It was always my understanding that those Max owners who are running 225/50s on their stock 16s had a slightly taller tire ratio vs the 215/55 because of the narrowness of the rim. I figured the 225/50 would be perfect of the 7.5" rim. They do make a 225/55, but it is too tall (25.3").

Dave

 

The aspect ratio of a tire is not derived from the width of the contact patch, but the width across the side walls (the tread width for a given size tire will vary from tire model to tire model). For every tire size, a manufacturer will give a nominal suggested rim width and a rim width range. For the tire you mention the nominal suggested width is 7" (which is what the rest of the tire measurments should be based on, since some depend on rim width). The stock rim width is 1/2" under, and you'll be 1/2" over, but they are both within range. If looks are a big concern, go with the 255/55's they are a fraction of an inch bigger in dia. I wouldn't worry about it.