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A general tire size question

I have a set of rims and tires that came (from the factory) with 225/60/17 tires. A friend just bought new rims (and tires) for his car, and is willing to GIVE!!! me the old tires (less than 10k on them), the catch is, they are 225/55/17

Can I safely run these tires? I wasn't sure if the 55 was width? If I was going to change the tire size, could I also go with a 225/65/17?

Thanks for the help.

This will explain everything you would ever want to know.
http://www.tirerack.com/tires/tiretech/techpage.jsp?techid=46

Quote:

Originally Posted by ekam (Post 356284)

Let me google that for you

ekam, I'm not looking for a tire size calculator, either you didn't read the question, or didn't understand it. I searched tire rack and google last night trying to find out if the difference in size will allow me to mount these tires safely before I posted. Some say it can be done, other say it can't.

Has anyone here changed the aspect ratio of their tire? I'm not looking for a tire size calculator, I'm looking for someone who has done it, and their experience with changing it. I realize OEM size would be best, but these tires are 730bucks - if it's safe to change the ratio by 5 (or not) I'd like to hear from you.

With that size, I assume it's not for a Boxster? They will be 1" smaller in diameter, which is a fairly large change, especially if the car has stability control. It may be within the safe range for ABS function though? I thought up to 5% Dia. change was OK for ABS, and you would be at around 3.2% change in diameter? Don't take that as Gospel though!

The 55 is the aspect ratio is explained in spinnaker's link. ( the tires section height is 55% of the section width of 225mm )

I installed a slightly wider, and taller tire on the front of my '06 ( 235 to 245 ), and it is right on the edge for my PSM. If I increase the front tire pressure a few Psi, the "traction control" starts kicking in.

Quote:

Originally Posted by stephen wilson (Post 356316)

With that size, I assume it's not for a Boxster? They will be 1" smaller in diameter, which is a fairly large change, especially if the car has stability control. It may be within the safe range for ABS function though? I thought up to 5% Dia. change was OK for ABS, and you would be at around 3.2% change in diameter? Don't take that as Gospel though!

The 55 is the aspect ratio explained in spinnaker's link. ( the tires section height is 55% of the section width of 225mm )

I installed a slightly wider, and taller tire on the front of my '06 ( 235 to 245 ), and it is right on the sdge for my PSM. If I increase the front tire pressure a few Psi, the "traction control" starts kicking in.

thanks, stephen. that was one of my biggest concerns the stability control. I've driven a car with the wrong tire sizes (wrong diameter) and the abs was setting itself off at random (very unsafe). Seems like such a small number, but I'd hate to mess with being safe.