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been trying to decide what psi to run my KO2 D rated 285/55r20 tires
This guide is intended to provide assistance in utilizing load and inflation tables when replacing tires with optional tire sizes including “plus sizes” that may not be listed on the vehicle’s tire information placard (T.I.P.) or in the owner’s manual. For inflation pressure recommendations for the original equipment (OE) size, refer to the tire information placard (T.I.P.) or owner’s manual. The T.I.P. is commonly found on the vehicle door edge, door jam, glove-box door, or inside of the trunk lid.
the link above says between 55 and 60psi as did bf Goodrich when I called them
P-Metric or hard metric tires on Light Trucks
When a P-metric or metric tire is installed on a light truck (SUV, pickup, minivan), the load capacity of the tire is reduced by a factor of 1.101 as prescribed by the Federal Motor Vehicle Safety Standards (FMVSS). For example, 305/50R20 has a maximum load capacity of 3086 lbs. If this tire is fitted to a light truck, then the actual allowable load capacity for the tire is 2805 lbs. (3086 lbs. divided by 1.1). If you replace the original tires with the exact same type (P-metric, hard metric, LT-metric, or flotation), size designations, and ply as the tires that were originally installed, just follow the vehicle’s tire information placard for proper inflation pressures. If, however, you apply a ‘Plus zero’ or plus-1, etc., fitment to a light truck, you must discount the replacement tire’s load by the 1.10 factor and ensure that the replacement tire has sufficient load capacity by inflation to support the load of the originally installed tires.
55-60 psi will beat the hell out of you and your truck both.
From the posted load table, LT285/55-20 is already good for 2030 lbs at 40 PSI. That's a higher load than your factory wheels were rated for. Your axles either.
You may want to go higher than that for lateral stability while towing, or for treadwear if the contact patch isn't right, but from a payload perspective 40 psi is plenty.
55-60 psi will beat the hell out of you and your truck both.
From the posted load table, LT285/55-20 is already good for 2030 lbs at 40 PSI. That's a higher load than your factory wheels were rated for. Your axles either.
You may want to go higher than that for lateral stability while towing, or for treadwear if the contact patch isn't right, but from a payload perspective 40 psi is plenty.
Thanks!
It’s amazing BFGoodrich said 60psi!
im gonna run it in the 40s, see how it goes. Probably 43 front and 41 back.
discount tire installed them and said always run what it says inside the door on the placard but I thought a heavier constructed tire might need more psi vs. a P-rated
I'd suggest 35 for daily driving and 40-45 for towing/max payload scenarios where you'd like more rigidity. The chart expresses adequate carrying capacity at pressures lower than 35 which would certainly make the ride more comfortable.
I run my D rated KO2s at 43psi. I check it with a tread depth guage every so often and its wearing pretty much evenly across the tire.
Same tire and I run around 41psi. Did an online chat with BFGoodrich when I first purchased the tires and they told me to run them at 55 psi! I tried that once and then quickly reverted back down to the 40-45 psi range.
im gonna run it in the 40s, see how it goes. Probably 43 front and 41 back.
discount tire installed them and said always run what it says inside the door on the placard but I thought a heavier constructed tire might need more psi vs. a P-rated
A case of cumulative CYA. Ford overspecs because they know that bubbas don't check their pressures nor follow their payload stickers. Goodrich's starting point is Ford's worst case overspec and they put their own safety factor on top of that.
60 psi would be about perfect if you were going to fill the tires today, not check them for the next year, and then drive four messicans and 30 bags of quikrete up one side of the mountain and down the other.
10-27-2018, 04:15 PM
Tire pressure going from P-rated to LT tire, does inside the door psi apply?
