What is the difference between a 225 and a 245...I take it that number represents the height of the tire? So is a 225 1 inch smalle or something like that?

 

225, is the width in millimeters.

lets look at a typical tire size,...225/50/16

225,...width
50,...the aspect ratio of the width,...or in this case, 50 percent of 225, from rim to edge of tire.
16,...the rim size.

i dont work in a tire shop, so i could stand to be corrected.
hope this helps, joe

 

The Higher The Number The Wider The Tire

 

Thanks for the replies ...
So the diff is 20 mm between the two in width then..
So since that is .787 inches...does anyone think I would run into an issue of putting those on the stock 87 iroc rims? It calls for 245, wanted to stay with a stock like Goodyear Eagle GT tire...unless someone knows where you can buy stock size tires...looked at Coker, tire rack and discount tire and the only size they have is that 225.

 

Yes there is a 20mm difference between the two sizes - yet a 225-55-16 and a 245-50-16 share the same overall diameter.

You will not have any problem putting a 225 width tire on a 16" x 8" IROC wheel - in fact the 245 tire really needed a 8.5" tire from the factory, but GM cheaped out and made them only 8" wide. BMW uses an 8" wheel to mount their 225 width tires, BTW.

Last week, I noticed that there were only 13 tires in the stock 245-50-16 size that are streetable (as in not true racing tires) - of those, only 3 would be considered summer performance. Keep in mind that tire manufacturers have been moving away from the 245-50-16 size for a few years now - but the 225-55-16 tire will work too.

 

Where were these tires in stock at?

 

Tirerack.com
Discount tire direct.com

 

Thank you sir