When using OEM size, regardless of the brand/model/type, I use OEM pressures unless I am trying to make minor adjustments to the handling of a car (not truck) while auto-crossing or at an open track day. In other words, in a performance environment, not normal driving on the street.
This seems off-topic, but since it has been brought up, the document titled "Load & Inflation Table Application Guide" on this Toyo page explains the method I use for determining tire pressure when using a tire size that is different from OEM.
To summarize the document mentioned above, here's my method:
Obviously, you should never exceed a given tire's rated load capacity or inflation pressure.
If you find the center of your tires wearing out faster than both outside edges, you are probably running too much pressure in your typical use or too little pressure if you are wearing out the both outside edges before the center.
This seems off-topic, but since it has been brought up, the document titled "Load & Inflation Table Application Guide" on this Toyo page explains the method I use for determining tire pressure when using a tire size that is different from OEM.
To summarize the document mentioned above, here's my method:
- Lookup OEM tire size and pressure in the Inflation Table to determine load capacity at OEM size/pressure. Lets say this is 1200 lbs.
- Find new tire size in table
- Determine new tire pressure required to match OEM load capacity (1200 lbs) by finding the column closest to 1200 and looking at the pressure required to for that load capacity. Since the table jumps 3psi at a time, you can interpolate between given values to find your pressure.
Obviously, you should never exceed a given tire's rated load capacity or inflation pressure.
If you find the center of your tires wearing out faster than both outside edges, you are probably running too much pressure in your typical use or too little pressure if you are wearing out the both outside edges before the center.
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