The Goodyear Viva tires are manufactured exclusively for WalMart. They should carry sizes for most passenger autos. To find your specific tire size you can go to http://www.walmart.com/cp/Find-Tires-By-Size/91087 and just type in your tire size.
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.
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.
You can find a set of light weight truck tires at your local tire retailer. They carry the size and brands you need for most vehicles. If not, try the local car dealership, they should be able to help you out.
15 inch tires the exact size was 215/75R15
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.
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.
The pressure in any tire is determined by the weight the tire is supposed to carry . For example , if a car is weighing 2000 kilos , each tire is carrying 500 kilos weight . The pressure in the tire should be such as to withstand this weight . Pressure is force divided by area . So the more the area of the tire connecting to the land , the less tyre pressure is needed to withstand the weight . The rear tires of the tractor are almost double the size of the front tires and carry three fourth of the weight of the tractor . So if the tractor weighs 2000 kgs the rear tires carry weight of 1500 kgs and the front tires carry weight of 500 kgs . But then the front tires are one half the size so the pressure there will be 2 X pressure in rear tyre X 3/4 . ( These are approximate calculations for illustration . ) So the front tire should have about 1.5 times more pressure than the rear tires .