We have changed my cars tires from P20570R15 to a P20575R15. Will this put my speedometer out? And will it make my speedometer to fast or to slow?Will changing my tires change my speedometer?Only if you seriously change the aspect ratio of the tires. For instance, if you take a 195/70/14 tire and replace it with a 205/60/14 tire, it will stay the same, but if you use a 205/70/14 it will be off. Your tire salesman should be able to tell you which ratio will keep you accurate. Keep in mind that the amount of error will also increase the faster you go. While it may be only slightly of at 5 mph, it will be more off at 70 mph.
In your case, I wouldn't be too worried.Will changing my tires change my speedometer?Car speedometers aren't 100% accurate to start with. The 75 series tires you have installed may be a tiny bit taller than the 70 series tires you had, but they're not that much different to make a noticeable difference in your car's speedometer readings.Will changing my tires change my speedometer?This will have no affect on your speedometer. The 205 is the height of the tire and the 75 %26amp; 70 is the width. Since the 205 is the same your speedometer will still be accurate.Will changing my tires change my speedometer?your speedo may be a couple on mph slow..ie your going 65 but speedo reads 62,,,not a big thing if you pay attention..75 series tires are a bit taller and spin slower..Will changing my tires change my speedometer?That depends on whether the 205 70r 15 is the factory tire size or not. If it isnt, likely your speedo has been wrong anyway. However, changing the tire size from 205 70 to 205 75 will not raise it much. For instance, if you are driving and your speedo says your going 60, then you will be actually going 61.8 mph. You will be going faster compared to what your speedo reads. Here is a link to help with these kind of figures. http://www.therangerstation.com/tech_libWill changing my tires change my speedometer?the middle number won,t change it any. now if you put say a 14 inch or say a 215 or 235 on it then your speedometer will be off.Will changing my tires change my speedometer?There are a lot of confused answers to you question, so let's start with the basics.
The 205 in your tire is it's width in millimeters (about 8%26quot;). The next number is the aspect ratio which is used to calculate the tire's height. You multiply the width by the ratio (it's a percentage). So, in the example you present you are increasing the percentage which means the tires will be HIGHER by 5% or 10.25 mm which is just under 1/2 and inch.
Using this new information you can calculate the tire's circumference and learn that the new tire is just a hair more than 3% larger than the original one.
So a 3% difference in circumference will affect your speedometer reading by -- guess what-- 3%. It makes no difference whether your speedometer was accurate before or not, the new tire will show a difference of 3% less than what it showed with the original tire. If it was already wrong, it will still be affected.
The reading on a speedometer is obtained by %26quot;counting%26quot; the revolutions of the tire and converting it into a certain number of miles (or kilometers) per hour, so a tire which travels a larger distance, because it is a longer circumference, will be actually going faster than a smaller tire which advances less when it makes one revolution.
It also doesn't make any difference how fast you are traveling, there will still be a difference of 3%, however, 3% of 10 mph, is, of course, less than 3% of 100 mph, but the difference still is 3%.
How do you find out if your speedometer is accurate? Find a stretch of road where you can mark off exactly one mile. Then travel over that stretch of road with your speedometer reading exactly 60 mph. Use a timer to see how long it takes you to travel that distance. If your speedometer is accurate, it will be exactly 60 seconds, if you take longer, your speedometer is reading high, and if you take less your speedometer is showing a lower-than-accurate speed.
End of speedometer class!
