Thanks so much, really appreciate it!
Tire Pressure recommendation (18 Viewers)
- Thread starter terdrocket
- Start date
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Markuson
SILVER Star
Gaijin,
I was going to ask you for 285/75/17 E Ridge Grapplers....but props to you...I searched this thread and found your answer to someone else! (And props to me for actually searching before asking...HAHA).
37 it is (ok...plus a couple bc I’m so stupid-heavy...)
THANK YOU as always to
the honorable...PSI Ninja!
-Grasshoppa
gaijin
GOLD Star
Gaijin,
I was going to ask you for 285/75/17 E Ridge Grapplers....but props to you...I searched this thread and found your answer to someone else! (And props to me for actually searching before asking...HAHA).
37 it is (ok...plus a couple bc I’m so stupid-heavy...)
THANK YOU as always to
the honorable...PSI Ninja!
-Grasshoppa
I love it when a plan comes together !
Gaijin,
I was going to ask you for 285/75/17 E Ridge Grapplers....but props to you...I searched this thread and found your answer to someone else! (And props to me for actually searching before asking...HAHA).
37 it is (ok...plus a couple bc I’m so stupid-heavy...)
THANK YOU as always to
the honorable...PSI Ninja!
-Grasshoppa
Lol. You’ll probably need +2 just for the skids you bought.
Markuson
SILVER Star
afgman786
SILVER Star
Gaijin,
Not sure if I missed this information in the thread. But out of curiosity I've understood to run higher PSI to get closer to the max weight rating of the tire. But then if you air down, the load rating drops on the tire.
Then how does this not cause an issue when on a trail and airing down to around 20PSI? Wouldn't the load rating of the tire drop to somewhere in the 1k area?
Also thank you for your knowledge! I've learned so much that I never knew mattered from everyone on this forum
Not sure if I missed this information in the thread. But out of curiosity I've understood to run higher PSI to get closer to the max weight rating of the tire. But then if you air down, the load rating drops on the tire.
Then how does this not cause an issue when on a trail and airing down to around 20PSI? Wouldn't the load rating of the tire drop to somewhere in the 1k area?
Also thank you for your knowledge! I've learned so much that I never knew mattered from everyone on this forum
gaijin
GOLD Star
The Recommended Cold Tire Inflation Pressure (RCTIP) for any tire, whether from my recommendation for custom sizes or from the placard on the door jamb for stock tires, is the minimum pressure required for "normal" on-road use up to the GVWR of the vehicle. The only time the Max. Load spec. for any particular tire comes into play is if it is less than the required Load Limit @ the RCTIP - in which case that particular tire is unsuitable for use. For example, a P-Metric or ISO-Metric tire used on a LC200 requires a Max Load spec. of at least 2,512 Lbs; a LT-Metric tire used on a LC200 requires a Max Load spec. of at least 2,286 Lbs. If a tire has a Max Load spec. of less than either of these, it is not suitable for use on a LC200.
Yes, when aired down to less than the RCTIP, the Load Limit of the tire becomes much less - certainly insufficient for "normal" on-road use. That is why tires should only be aired down for specific off-road use, and even then, only for use at reduced speed and with increased caution to avoid any kind of shock or abuse that could cause a tire failure - i.e. don't go charging any rocks or ditches at increased speed when aired down, the tires can't withsatnd the abuse. Slow and steady wins the battle there.
So, yes. There is a definite "issue" when aired down. When the circumstances that caused you to air down in the first place - increased traction, usually - are no longer in play, it is important to air back up as soon as possible. While aired down, increased stress is placed on your tires, especially the sidewalls, which will over time decrease the useful life of the tire.
HTH
afgman786
SILVER Star
Thanks for passing along the knowledge @gaijin I understood less air for better traction, didn't learn about that equal less load rating until reading what you have posted through this thread.
Going to bug you with one more question related to pressure if you don't mind.
Now the weather is getting warmer I'm sitting around 36PSI cold, however after driving around gets to afternoon time my pressures get up to around 39PSI. Should I drop my cold pressure a bit so that I'm not running at around 38-40?
Going to bug you with one more question related to pressure if you don't mind.
Now the weather is getting warmer I'm sitting around 36PSI cold, however after driving around gets to afternoon time my pressures get up to around 39PSI. Should I drop my cold pressure a bit so that I'm not running at around 38-40?
gaijin
GOLD Star
The simple answer is, "No."
It is normal that tire pressures will increase after driving, that's why the tire pressure is set when the tires are cold - meaning not having been driven on for at least 4 hours, not allowed to sit in the sun, and fully equilibrated with ambient air temperature.
One can be driven crazy trying to continually adjust tire pressure based on changing air temperature. Ideally, whenever air temp changes, one should allow tires to re-equilibrate with ambient air temp and re-adjust pressure. Practically, it is only necessary to re-adjust tire pressure when there is a significant change in either ambient air temp or elevation. What this means is that if one checks tire pressure once a week at the coldest part of the day (usually first thing in the morning) and adjust to RCTIP, you're good to go.
Notes on when to set RCTIP:
- Assure tires are cold and fully equilibrated to ambient air temp
- Check regularly and adjust when necessary
- Check and adjust when air temp or elevation changes significantly
- If checking/adjusting tire pressure in a protected environment, e.g. heated garage, adjust tire pressure to compensate for outdoor ambient air temp
Concerning the last point, here's what Toyota recommends for compensation:
HTH
I was under the impression this was an LT rated tire and should run at closer to 44 psi. Is this tire, even with the extra load, P rated?
gaijin
GOLD Star
The Michelin Latitude Tour HP 285/60R18/XL 120V is most definitely NOT an LT-Metric tire. The correct pressure for use on a LC200 is as I stated - 33psi F/R - 44psi would be grossly overinflated.
The correct descriptor for this kind of tire is ISO-Metric. If it were LT-Metric, it would have LT in the size molded into the tire sidewall, e.g. LT285/60R18 - it does not. If it were P-Metric, it would have P in the size molded into the tire sidewall, e.g. P285/60R18 - it does not. When there is no designator before the metric width on the tire sidewall, it is an ISO-Metric tire - like the one you asked about.
In fact, looking at the Michelin web site for the Latitude Tour HP, there are NO sizes which are LT-Metric - all tire sizes are either P-Metric or ISO-Metric. See the web page here: Michelin Latitude Tour HP Specifications
Sorry, but even with the XL rating, this is not an LT rated tire.
Do have this tire? Or are you just posting out of concern that I gave the wrong RCTIP to @Ninja Cruiser100 ?
HTH
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Gaijin, Searched, but couldn't find. Looking for recommended pressure for Nitto Ridge Grapplers 285/70r18. 2013 with ARB bumpers.
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gaijin
GOLD Star
Nitto does not make a Ridge Grappler in size 285/70R18, so I must assume you meant the LT285/70R18 E 127/124Q Ridge Grapplers. I also assume you are putting these on a LC200 and not an LX570.
If both of my assumptions are correct...
The Recommended Cold Tire Inflation Pressure for the LT285/70R18 E 127/124Q Nitto Ridge Grapplers on your 2013 LC200 is 38psi F/R.
HTH
Thank you! My bad for not better clarification, nonetheless your assumptions are correct.
Gaijin, I know I know, stupid questions get stupid answers, but I have to ask anyway... I could swear that I read somewhere that 40psi (maybe 38?) was the minimum psi for LT tires?
gaijin
GOLD Star
Stupid is as stupid does
35psi is the minimum pressure recommended for use on any LT-Metric tire according to the Tire and Rim Association (TRA) - the "governing body" for tires and wheels as used by tire, wheel and automobile manufacturers. Check the TRA LT-Metric Load/Inflation tables as published by Toyo on pages 20-25 here: TRA Load/Inflation Tables and Guide
Hope your wrong answer doesn't land you in summer school.
HTH
Thank you! And thank you for proving the maxim wrong, as the stupid question did not, by any means, produce a stupid answer.Stupid is as stupid does
35psi is the minimum pressure recommended for use on any LT-Metric tire according to the Tire and Rim Association (TRA) - the "governing body" for tires and wheels as used by tire, wheel and automobile manufacturers. Check the TRA LT-Metric Load/Inflation tables as published by Toyo on pages 20-25 here: TRA Load/Inflation Tables and Guide
Hope your wrong answer doesn't land you in summer school.
HTH
Tire God Gaijin. What is the correct cold inflation pressure for a Nitto Trail Grappler 285/75R17 on a 2014 200 series sitting at 7400lbs? Thanks (not sure if this tire is different than the ridge grappler recommendation listed above on this page?)
gaijin
GOLD Star
Nitto does not make a Trail Grappler in size 285/75R17.
Is your "200 series" a LC200 or an LX570 - Land Cruiser is a URJ200L while the LX570 is a URJ201L, both in the "200 series." Recommended Cold Tire Inflation Pressure (RCTIP) is different for the LC200 and the LX570.
7400LB is above the GVWR of either the LC200 or the LX570. I only give RCTIP for up to the GVWR of your vehicle. If you choose to operate above the GVWR, that's on you.
/Rant Over
I'm tempted to stop here, but being the nice guy I am, I'll continue with some assumptions - please advise me of any faults in my assumptions.
Nitto does noty make an ISO-Metric tire in 285/75R17, so I had to go to the Nitto web site and confirm that the tire you are probably asking about is the LT285/75R17 E 121/118Q Nitto Trail Grappler M/T. If that is not the case, please let me know.
I went back over some of your previous posts and found that you mentioned owning a "landcruiser" so I assume you have a LC200. If that is not the case, please advise.
In light of the above assumptions, the Recommended Cold Tire Inflation Pressure for the LT285/75R17 E 121/118Q Nitto Trail Grappler M/T tires on your LC200 is 37psi F/R. This pressure is good up to the GVWR of 7385LB.
HTH
Thanks, @gaijin. I do have this tire. And it seems like I have it grossly overinflated - currently running at 44psi. I will defer to your knowledge on this topic.
I will say it doesnt look overinflated and has been wearing evenly with regular rotations. I will try it at 33 for a while and see how it goes. I actually bumped it up a bit as it felt squishy to me on the highway. To me, it seemed much more stable at the higher PSI.
The alternative is that some suspension components need to be addressed. I am at 120k on a 2013 so this is quite possible.
