Hey guys, I just put on a new set of BF Goodrich KO2 LT285/75/16 116/113R load range C on my 80. Does anybody know the recommended cold tire pressure for use in an 80? It says on the sidewall max load of 2755 lbs @ 50 psi cold. I previously had Cooper Discoverer STT load range D LT285/75/16 and was advised by a fellow from the 200 section that the recommended pressure was 38 psi. That tire had a max load of 3305 lbs @ 65 psi cold. Thanks in advance!
Recommended tire pressure for KO2 LT285/75/16 116/113R load range C?
- Thread starter HRTROB
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I run 'em with 50 PSI on tarmac.
32psi on mine.
My KO2 in 315/75 have a higher load rating. I run my tires at the recommended 32 or whatever is on the door jam. I have gotten extremely even tire wear as well luckily. When I go and get the tires rotated the guys can't believe my tire wear for having almost 10K miles on my KO2.
- Thread starter
- #6
I think you guys may be under-inflated at 32 psi on tarmac. The 32 psi recommendation on the door jamb sticker is for the stock P-metric tire. LT-metric tires require higher cold tire inflation pressures...
LC4LIFE
Supporting Vendor
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tampacruiser95
Upgrades are coming.
I run 38 on mine
I have load range e tires and I run 60-65, max is 80
Most run too much pressure
Do the chalk test if you're concerned about getting the best tread life out of them. Most people over-inflate them so the center of the tread will wear prematurely.
If you don't care about max tread life, then just let the air out until you like the way it rides/handles. I find somehere in the 32-33 ballpark is ideal for me (e-rated 315s). I pump them up to about 40-42 when towing the camper, and air them down to about 16 off road.
If you don't care about max tread life, then just let the air out until you like the way it rides/handles. I find somehere in the 32-33 ballpark is ideal for me (e-rated 315s). I pump them up to about 40-42 when towing the camper, and air them down to about 16 off road.
gaijin
GOLD Star
I only do recommendations for 200 Series, but I can tell you that there is a lot of very bad info in this thread.
If you want to correctly determine the Recommended Cold Tire Inflation Pressure for tires on your 80 Series, you can easily do it by reading the publication by Toyo Tires about just this question - available here: Toyo Guide to Load and Inflation Tables
I have detailed my methodology several times so I'm not going to do it all again here, but basically you need to follow these steps:
1. Determine the tire type and RCTIP for the tires supplied on your vehicle OEM by Toyota
2. Look up the Load Limit for those tires using the RCTIP found on the Tire Information Placard found on the door jamb
3. If the new tire is the same type as OEM (e.g. P-Metric OEM and P-Metric substitute) just look the new tire up in the tables and find the pressure that yields the same Load Limit.
4. If the new tire is not the same type as OEM (e.g. P-Metric OEM and LT-Metric substitute) divide the OEM Load Limit by 1.1 to determine the required Load Limit for an LT-Metric tire.
5. Look up in the tables for LT-Metric tire the pressure that yields the required LT-Metric Load Limit
6. ISO-Metric tires have their own tables and use Load Index to determine required inflation
7. Flotation tires also have their own tables.
It's science, and it works. A "Chalk Test" is the easiest way to get yourself in trouble - unless, of course, you are the design engineer for the tire in question and have a detailed knowledge of the desired tire footprint for the required tire Load Limit for the vehicle in question (Hint: nobody knows this).
HTH
- Thread starter
- #14
Yesterday I went to the trail and the drive up was about 70km. Tires were aired up to 38psi and when I got there I aired down to 28psi. On the way home I had to drive back about 40km @ 28psi and I noticed that the tire temps were getting hot (I have an aftermarket TPMS). Tires reached 44 deg C. When we finally got to a gas station and aired up, temp went down by 10 deg C and stayed cool until we got home. So yes, running a lower pressure than normal really does pose a danger. I believe you guys running the load range E with max load @ 80 psi are way under-inflated at 32psi. We need to find somebody good at math to help us determine the correct pressure for our tires
Jack90210
SILVER Star
Here's the math, @HRTROB
I used the Toyo Tires load tables posted above.
Looking up my tire sizes, I'm seeing that 32psi (factory spec for rear tires) on stock size tire 275/60R18 (for my LX470) carries the equivalent load at 50psi on an LT-rated tire of size 285/70R17.
To repeat the above, LT tires need higher pressures to carry the equivalent load of a P-rated tire.
EDIT: I did not factor the 10% load de-rating that is applied when P-rated tires are used on SUVs. If this is done, I come up with an equivalent load at 40psi per this tire pressure calculator.
I used the Toyo Tires load tables posted above.
Looking up my tire sizes, I'm seeing that 32psi (factory spec for rear tires) on stock size tire 275/60R18 (for my LX470) carries the equivalent load at 50psi on an LT-rated tire of size 285/70R17.
To repeat the above, LT tires need higher pressures to carry the equivalent load of a P-rated tire.
EDIT: I did not factor the 10% load de-rating that is applied when P-rated tires are used on SUVs. If this is done, I come up with an equivalent load at 40psi per this tire pressure calculator.
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I would say 44C is perfectly acceptable for tire temperature after driving 40km, especially if your ambient temperature is above 30C. Looks like most TPMS warnings kick in at 70C.
With your bumpers and additional load try 35psi and see how it does. I agree that running too low will cause issues, however there is a sweet spot where you get a smooth ride, good traction, even wear, predictable handling, and good enough off road performance that you don't have to air down (usually).
