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Tire size just making sure
Posted: December 2nd, 2007, 7:03 pm
by tastethefear
The 195/55/R15 will fit on the stock 15 inch rims right. Since standard 205/55/r15. What will the difference be on the 195 to the 205?
Posted: December 2nd, 2007, 8:24 pm
by 95 rs
it will be slightly narrower and shorter.
Posted: December 2nd, 2007, 11:07 pm
by tastethefear
so they will fit?
Posted: December 3rd, 2007, 8:40 am
by 95 rs
they should
Posted: December 3rd, 2007, 12:13 pm
by wytbishop
205/55/R15...
205 is the thread width in mm.
55 is the aspect ration of the tire wall. That's the height of the tire wall from the lip of the rim to the tread as a percentage of the tread width. 205*.55=112.75mm
R is the speed rating of the tire.
15 is the size of the rim the tire is made to fit in inches.
Overall tire diameter then is 15" + 2(205*.55/25.4) = 23.88" for the stock tire size.
work it out and 195/55/R15 is 23.44" about .44" smaller in diameter, which corresponds to 1.38" less circumference. That means for every revolution of the wheel the car travels 1.38" shorter distance.
Now road speed is measured off of the differential gear so at a given rpm the speed displayed on the speedo is derived based on the stock tire size and the wheel traveling a certain distance for every revolution. The speedo doesn't know you've changed the tire size. So at a given diff speed, now the wheels are traveling a shorter distance and the speedo will read high...but not much. The more common problem is guys putting 17's with say an inch larger overall diameter. That's over 3inches more travel per revolution. Their speedo's will be noticably low.
I know 99% of you know this...but I'm bored.