The original tire size for a Massey Ferguson 135 is 6.00 x 16. For most applications, this is the best tire size for the Massey Ferguson 135. However, if you want to find a wider or narrower tire size, there are other options available. For instance, a 6.50 x 16 is a wider tire option for the Massey Ferguson 135. If you want to go with a narrower tire size, you can opt for a 5.50 x 16. Additionally, there are narrow tractor tires available that are sized 4.50 x 16.