So I know this may be a silly question, but I recently bought tires for my car that are 5% less in aspect ratio than the originals. I went from 205/65/15 to 205/60/15's. Will this dramatically impact the safety of my driving and/or vehicle? Any assistance is greatly appreciated.
No. The only thing different is the tire width. If anything, its safer. Your footprint to the road surface is larger now.
October, 6, 2013 AT 3:03 PM
I read that wrong, sorry. You went down in width. I wouldnt say its unsafe, its such a small amount you went down, im sure you wont notice any change. Your fuel economy will increase though!
October, 6, 2013 AT 3:11 PM
Oh okay. Good to know. I went from 65 to 60, which is the depth of the sidewall, correct? I just wanted to be certain. I appreciate the help!
October, 6, 2013 AT 3:14 PM
No, 60 is the width of the tread.(Your 65 would have been a little bit wider) 205 is the height of the sidewall from the rim to the outermost part of the tire. And 15 is obviously the rim size. Hope this helps.
October, 6, 2013 AT 3:19 PM
Okay. I may have had it backward. From what I saw on a tire website, this is what I was referencing: Width: 205
This number is the width of the tire in millimeters. This is the most important number to describe a tire's contact patch.
For example, a 215-width, 17-inch tire may look great, but all things being equal, a 245-width, 15-inch tire will out-corner it every time, because the contact patch is wider.
Aspect ratio: 50
This is the height of the sidewall from the rim to the tread, expressed as a percentage of the tread width.
For example, if the tire is 205 mm wide, and its aspect ratio is 50, then the sidewall is about 102.5 mm tall (50 percent of 205 mm).
Sidewall height is important for a number of reasons: As you move up to larger wheels, or down to smaller ones, a corresponding change needs to happen in the sidewall height of the tire in order for the rolling diameter of the wheel and tire combination to be as close to stock as possible. This will ensure the accuracy of your speedometer and prevent unwanted alignment changes.
The sidewall height affects the turn-in feel (the responsiveness you feel at the steering wheel) and the ride quality.
Lower aspect ratio (shorter sidewall) provides better turn-in response than a higher aspect ratio, but at the expense of less break-away warning and a more jarring ride in extreme cases, even exposing the wheels to potential bending and breaking damage from potholes and other surface irregularities.
So this is why I was concerned about the depth of the sidewall, if that makes any sense?
October, 6, 2013 AT 3:25 PM
Ive been under the wrong idea all these years. Wow! You are 100% right. I just did some digging into this. The 1st number-205 is the tire width, second is the height to width ratio. And 3rd is your rim size. Again, I appoligize. Im at a loss of words.
October, 6, 2013 AT 3:28 PM
Not a problem! I just wanted to be certain.
So, now that we're on the same page with each number's designation, do you think the slimmer aspect ratio by 5% should be a major concern, or should I go ahead and use them?
I suppose my main concern is safety of the vehicle and its occupants, and secondarily the ride and tire longevity.
October, 6, 2013 AT 3:33 PM
Safety will not be an issue. You have a smaller diameter tire now though, so your speedometer may be off. Your tire will make more revolutions then the original 65. This means if your speedometer is reading 70, your actual speed will be slower. Not by much- at highway speeds, maybe 2-4mph.
October, 6, 2013 AT 3:55 PM
Alright; thank you for the assistance, I really appreciate it.
I actually bought the 205/60/16's in error, but in an effort to return them I figured I'd ask you guys (since I bought online)
I wanted to make certain my tire guy won't yell at me when I take the car in to mount the tires and align on Friday.
October, 6, 2013 AT 3:58 PM
Haha. I hear ya. He wont yell at you. You did just fine. Thanks for your help, as you actually taught me something! I still cant get over the fact that I have been wrong all these years.