Understanding Tractor Tire Sizes

Have you ever wondered what all the numbers mean on your tractor tires?

No worries if you do not. 

We want to help you understand them and promise to keep this simple. 

Here we go. 

Tire Style #1

Let’s say that you have a style that looks like this… 9.5-22

“9.5” is the width of the tire in inches.  “22” is the diameter of the rim in inches. 

So, if you have a 22" rim, you can put an 8.3-22, a 9.5-22, or a 10-22 on the same rim without any issues. 

Tire Style #2

There is another style that looks like this… 200/50/18

“200” is the width of the tire in millimeters.  “50” is the aspect ratio --- which means that the tire is 50% as tall as it is wide = 100mm.  “18” is the diameter of the rim in inches.

Pretty simple to understand right? 

There is another question that pops up quite a bit…

Can I put on a bigger tire?    

The short answer is “usually” --- but not “always.”  Let us explain.

You can almost always put on a tire that is slightly wider or narrower (10-20%) if the rim size is the same.

If you want to change to a wider tire, you will need to divide the diameter of the rear tire by the front tire on both the new set and the old set.  The numbers must be within a few percent of each other to work.  Check with your dealer or local mechanic for more detailed information. 

NOTE: If your tractor is 4wd, then you must keep the same front to rear tire ratio.

If you do not, the gears will be working against each other.  This happens because the front and rear tires are trying to roll at different speeds.  Ultimately, this will destroy your 4wd system.  It will be very expensive to fix.

If you have a 4wd tractor, stay with the same size tire.  If you took off a 5-12 --- install another 5-12.  This keeps it simple for you.

If we did not address your tire style, it may be listed in metric or standard sizing instead.  Consult your service manual for more details.

If you need any further help or have any questions about tires/rims, tractors, or anything else, please contact your dealer, local mechanic, or call us at 602-734-9944.  Please ask about our current new and used tractor supply.

Team Tractor Ranch – #1 Tractor Dealer in Arizona. We sell and service most major brands of tractors including Yanmar, Kubota, John Deere, TYM, Mahindra, Kioti, Case, New Holland, Massey Ferguson, Ford, Deutz, Case IH, Farmall, International Harvester, Branson Tractors, LS, Shibura, Claas Tractor, McCormick Tractors, Valtra, Solis, YTO, Montana, and Nortrac.