Width and Profile which is height.
By ratio if you mean size, the answer is no unless the car comes from the factory with a different size rear tires than front tires like some sports cars. In that case you would have 2 tires the same size on the front and 2 tires another size on the rear. You should never ever run 2 different size tires on the same axle. Therefore you would never have a situation where you would have 3 tires one size and then 1 tire another size.
One companies that make 265 75 16 size of tires are Pepboys. Another company is expeditionalportal. These companies offer these tires in their stores.
First off you should not install tires that are not the correct size. But if you do, make sure the tires on each axle are both the same size. Both front tires same size, and both rear tires same size.
Tires come in every possible size you could imagine.
Use this web site http://www.michelinman.com/tires/find-by-vehicle/ Another good site for tires is www.tirerack.com. Has compatibility charts and size calculators and the free phone support is excellent.
Tires Size - 215/60/R15" Rim Size - 15 inches
form_title= Tire Size Calculator form_header= Drive with the right size tires Want size tires do you currently have?*= _ [50] When were your tires last replaced?*= _ [50] Do you want to change tire size?*= () Yes () No
All the tires should be the same size. If the other tires are in place you should be able to get the size from the other tires. If not the size should be on a plate inside the drivers side door with many other specs.
15 inch tires the exact size was 215/75R15
volume
form_title= Tire Size form_header= Drive like a pro with new tires. Want size tires do you currently have?*= _ [50] When were your tires last replaced?*= _ [50] Do you want to change tire size?*= () Yes () No
If all four tires on an MTB bicycle are 26 by 2.10, they are the same size.