understanding tire size on my 2003 grand am GT

Hi, i did some searching but still confused, my car should have 225/50R16 on it and when i bought it last week it has 205/55R16 on it, are they actually the same or are the 225/50 a little wider?

Im gonna buy some new tires but want to make sure i buy something that looks good and not to skinny!!

The numbers in a tyre are 3 different things.

The first set of digits refers to how wide the tyre is in milimeters, the second number is how high the tire is, as a percentage of how wide it is, and the final number is the rim size, in inches.


So your current tyres are 20mm to narrow, but have a higher side wall profile so have the same over all diameter.

You should get what's on the door. If you want to use other size you need to do some conversion to be sure it do give the same diameter. If you are where there is snow, it is common to use narrow tires for the winter one and normal for summer. Narrow slice throught the snow better. Ex: my winter tires are 195/65R15, but my summer are 225/50R16. Notice the few conversions there: both set have the same diameters (actually, 0.53% difference) but different width and rim size, so the sidewall does change alot!

http://www.1010tires.com/tiresizecalculator.asp is a good place to compare the tire size. STAY WITHIN 3% OF THE STOCK TIRES!

k thanx guys, but over all the correct size will be better and look better than what is on it now

k thanx guys, but over all the correct size will be better and look better than what is on it now

You won't see a lot of difference.

The sidewall will be exactly the same height.

205 x .55 = 112.75mm
225 x .5 = 112.5mm

So a quarter of a mm difference in sidewall height, which is so small you could never see it.

They will be 20mm wider, which is only about half an inch, so also hardly noticeable.

from the side you won't see any difference. the diameter is exactly the same.

From the front or rear you will see a slightly difference, but not enought to really notice it...

205 vs 225... 20mm difference, about 13/16" difference.

Don't change for the look. It won't make a difference.

Change only if damaged or worn out or for better performance tires. ex. replace "triangle" by good year. Don't know what is "triangle"? don't worry, nobody knows what is that brand... but those tires are about as bad in snow as bald tires are!

Wants some better looking one? you probably want some low profile one. you would need to get some bigger rims (mags?) and expensive tires... like those 18-20" rims... pricey and cop magnet.