Does anybody knows what size of a tire or rims size that's go's on a bmw x3 the up and down size. thanks

For tyre sizes do you understand what all numbers mean? I've described them below just in case you don't.
If your changing tyre width you need to adjust the side wall size. Changing the rim size will also need the same adjustment. Generally a narrower tyre will need a taller side wall to keep the wheel size correct. The wrong tyre size will affect your speedo reading and affect the handling and grip of the vehicle.
To drop to a 16 inch rim the 225/55R17 would have to be either a 255/50R16 or a 215/60R16.
To go up in rim size the 195/70R16 would have to be a 255/45R17 or a 285/40R17.

Using the 225/55R17 - 6.5J x17 as an example.
Tyre size.
- 225 is the width of the tread on the tyre in mm.
- /55 is the side wall measurement as a percentage.
- R is the tyre is a 'Radial' construction type.
- 17 is the rim diameter in inches.
Rim details.
- 6.5 is the width of the rim between the points where the tyre attaches to the rim.
- J is the code for the shape of the seal edge.
- 17 is the rim diameter in inches.

Nope.

NO a 16" rim fits a 16" tire, and a 17" rim fits a 17" tire
How to Read Tire Sizes Goodyear Auto Service Center
http://www.tirerack.com/tires/tiretech/techpage.jsp?techid=46

Of course you can. Just make sure that the rim and tire is for your vehicle. A junker, or wrecker is your best bet, but if you want brand new, of course, just drop into your local dealer. Won't be cheap though!

Hello, Thank you for trusting FixYa.com to help get you going! The rims on your Cherokee, (and any other vehicle) are measured based on the tire that is designed to fit it. Technically the rims is just shy of 17". They measurement is taken at the base of the lip at the tire seat, ( the place on the rim that the tire seals against.) There are many outlets with rims for sale from custom to OEM, available in almost every city in America. Depending on the look or function that you are seeking, prices range greatly. Good luck, and if you have additional information, questions, or comments please return, and I will respond quickly to your concerns. Thanks again for trusting FixYa.com, have a great day!.

the stock rims should be 16" making the tire size 205/55/16. let me know if you have a different rim size. you can look at the tire size on the tire sidewall and the last number is going to be your rim size. if it's a 15' rim the tires are 195/65/15 and finally for 14" rims the tire size is 195/70/14. hope this helps.

2008 BMW 323i 4 door sedan - factory wheel rim size

Rim size (standard factory spec):
16 inch by 7 inches wide.
Front and rear are the same size.

(It is possible to fit 17 or 18 inch rims to the car if you wish together with an appropriate lower profile tyre ).

(please note that different models in the 2008 3 series BMW have different size rims. For example, the 328 and higher level models runs larger rim sizes).

Hope this helps. Cheers

Wow, this is an unusual problem. What year? Factory wheels or aftermarket? Tire size? Are the tires losing air pressure so that the rims are 'slashing the tires?' Are the rims cutting through the side walls of the tires? How many or the tires did this happen to and how many times??

Ticking posably but unliky.
18" vs 17" only if the wrong size of tire was mounted.
18" is only 1/third of the tire size, there is tread width and side wall hight.
wrong size can realy change how the car proforms, handles and rides.

my car has 15" rims, it works nicely, hmmm I'd say 16" rims are probly about as high as you could go without needing lower profile tires and keeping the car's performance...