Why? They are way taller and far skinnier giving you less traction because of a smaller contact patch.

Didn't know 225's were skinnier than 225's. My understanding was the 55 and 75 are aspect rations,yes making them taller, not skinnier. Maybe I'm wrong, just looking for information on if they would fit the car.

Look up a tire chart... 75's are way skinnier than 55's. Rolling diameters are different too. Easy to find them for any specific brand tire... read those and learn...

A 225 is simply not a 225 any more than a 16" is a 16". You have to look at all three numbers, AND STILL refer to the manufacturares charts as they even vary from manufacturer to manufacturer with supposedly identical sizes.

The aspect ratio is the percentage of sidewall. The 225 is bead to bead... aspect ratio WILL effect diameter and thus circumference.

Quote:

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Originally Posted by blundond

Can I put 225 75R16 tires on a 2007 CTS (regularly 225 55R16 tires)?

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Tire sizing 101:
* the first numbers indicate the tire width, measured in millimeters, sidewall to sidewall, properly inflated on an approved rim.
* the second number is called the aspect ratio. It is a measure of sidewall height as a percentage of the width.
* the last number is the approved rim size, measured in inches.

More on that if you're interested:
http://www.tirerack.com/tires/tirete....jsp?techid=46

http://www.ehow.com/how_2364482_read-tire-sizes.html

So, the tire sizing you are considering would be taller, thus they probably won't fit that particular vehicle, clearance being only one issue.

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Thanks Cap'n. Appreciate it.