Tire Pressure recommendation (10 Viewers)

[gaijin]

Never heard that little tidbit on the reset function about individual settings...and the 25% warning trigger.
PSI Ninja strikes again!

I keep my spare at the max inflation pressure indicated on the sidewall, but inflate the other four tires to proper inflation. The overinflated spare gives me a small air reserve I can use to put air in another tire in an emergency situation with a simple valve-to-valve hose. The dash central display shows all the pressures with 4 looking normal and one much higher - easy to identify the spare.

In the case of my highway tires (P285/60-18) the 4 mounted tires are at 33psi and the spare is at 60psi. After checking pressures, these are the pressures at which I reset the TPMS. The TPMS will trigger when any of the mounted tires goes down to < approximately 24.75psi or if the spare goes down to < approximately 45psi.

I once tested the displayed pressures in the central display against my pressure gauge by changing pressure in 0.1psi intervals for each tire. Long story short, the displayed values are not as accurate as a good tire pressure gauge and are not the same from tire to tire. Bottom line is, in an emergency, one could use the displayed pressures to adjust/set tire pressures; but it is much better to use a good stand alone gauge.

HTH

 

[LandCruiserPhil]

If one wants to geek-out on proper air pressure for a given tire and vehicle weight the attached is for you.

 

[BabaBear]

The recommended Cold Tire Inflation Pressure for the Nokian Hakkapeliita R2 SUV 275/65R18 116 R tires on your 2016LC is 33psi.

HTH

Thank you sir!

 

[NCFJ]

I chalk my tires, it's pretty simple. Been doing it for almost 40 years and my tires wear even.

 

[Dan Lee]

Interesting thread. I figured out how to calculate recommended tire pressure using the tables and tire sizes Gaijin linked to. Never knew about this stuff my whole life. Great info and I'll keep this in mind when I replace my tires (well, it's already posted above what tire pressure to use ). Thanks!!!

One thing: it was interesting to learn that the TPMS sensors trigger a warning at 25% deflation. This is my first car with TPMS (I just bought the car a month or so ago). Is it bad practice to reset the TPMS at 55psi so that I get the warning at ~42psi with a set pressure of 46psi? Basically, if the cold pressure is 46psi, I want to know earlier that the pressure is getting low (say, after a 10-15% drop). Maybe I'm leaking air / got a slow leak or something. Or is there a way to set the warning at 10-15% rather than 25%? Or maybe there is a reason why the warning is triggered at 25%?

 

[gaijin]

Interesting thread. I figured out how to calculate recommended tire pressure using the tables and tire sizes Gaijin linked to. Never knew about this stuff my whole life. Great info and I'll keep this in mind when I replace my tires (well, it's already posted above what tire pressure to use ). Thanks!!!

One thing: it was interesting to learn that the TPMS sensors trigger a warning at 25% deflation. This is my first car with TPMS (I just bought the car a month or so ago). Is it bad practice to reset the TPMS at 55psi so that I get the warning at ~42psi with a set pressure of 46psi? Basically, if the cold pressure is 46psi, I want to know earlier that the pressure is getting low (say, after a 10-15% drop). Maybe I'm leaking air / got a slow leak or something. Or is there a way to set the warning at 10-15% rather than 25%? Or maybe there is a reason why the warning is triggered at 25%?

Interesting question!

If you want to run your tires @46psi and want the TPMS to alert @42psi, I see no reason why you couldn't first inflate your tires to 56psi, reset the TPMS, then deflate your tires to 46psi. The system should then alert at 75% of 56psi which would be 42psi. It would require a 45*F temperature drop from the ambient temp at time of TPMS reset to cause the 4psi drop, but that should be manageable.

I have not tested this, so you should try it out on a tire first to see if it works - manually deflate from 46psi to 42psi in 1psi increments and see if that triggers an alarm.

HTH

 

[gaijin]

Good question! Here's a page from Technical Service Bulletin T-SB-0345-08 issued by Toyota which addresses the question:

This TSB is aimed at tire pressure adjustment on customers' cars when the pressures are set in a heated workshop, but will be driven in colder temps. Good news is, it fits your question perfectly.

All you need to do when setting the Cold Tire Inflation Pressure of your tires is to note the difference between the ambient temp when you are filling your tires and calculate the difference between that temp and the coldest temp you anticipate experiencing during the winter and set you pressures higher accordingly.

For example, let's say you are setting the pressures in your tires to 43psi and the ambient temp is 80*F. You expect to be driving in colder temps over the next few months, let's say that the coldest temp you expect to experience is 44*F. The difference between the temp at which you set your pressure (80*F) and the coldest temp you expect (44*F) is 36*F. Look on the X-axis of the chart (marked "5") and find 36*F. Then follow that line up until it meets Line "1" and follow that over to the Y-axis where you will see approximately "3" psi. This means you should set tour Cold Tire Inflation Pressure to 43psi + 3psi = 46psi.

And you're worrying about being too anal ...

FYI, here's an updated version of the TSB:

HTH

 

[LostRoad]

I have a new to me 2008 LC that came with P265/60/r18 Radial Long Trails. The tires looked and felt low so I looked at the tables provided and my understanding from these tables is the the tires are totally inadequate for this vehicle. The table cuts off at 35psi and the max inflation pressure is 44psi. If I extrapolate the numbers out I get an inflation pressure of 41psi for these tires but I am guessing these values are missing for a reason. I have new 275/70r18 nitto ridge grapplers on order but would appreciate advice on what pressure to run these at until the new tires arrive.

 

[NMNORSSE]

I have a new to me 2008 LC that came with P265/60/r18 Radial Long Trails. The tires looked and felt low so I looked at the tables provided and my understanding from these tables is the the tires are totally inadequate for this vehicle. The table cuts off at 35psi and the max inflation pressure is 44psi. If I extrapolate the numbers out I get an inflation pressure of 41psi for these tires but I am guessing these values are missing for a reason. I have new 275/70r18 nitto ridge grapplers on order but would appreciate advice on what pressure to run these at until the new tires arrive.

Your tires are p-metric and have a max psi of something around 35, which will be marked on the sidewall. Inflating to 42 and driving would be dangerous and probably a bouncy unpleasant ride.

 

[LostRoad]

Max inflation on the sidewall does list 44psi, hence some of my confusion. Max load 2271 lbs for what thats worth as well. Maybe I'll get lucky and the new tires will show up at Discount Tires sooner rather than later.

 

[Virgilus11]

Gaijin,
i recently installed a set of Yokohama g015 LT 315/70/17 with max 65 psi on the wall, on my GX 460. The tire shop is telling me that the pressure should be what Lexus wrote on the door jam. 32/ 32 front and rear. Are they correct ??
Thank you for your wisdom.

 

[NMNORSSE]

Max inflation on the sidewall does list 44psi, hence some of my confusion. Max load 2271 lbs for what thats worth as well. Maybe I'll get lucky and the new tires will show up at Discount Tires sooner rather than later.

My apologies, I was mistaken. Those are L/T not P-metric.

 

[LostRoad]

My apologies, I was mistaken. Those are L/T not P-metric.

No apology needed. The tire distinctly says P265 so if it is an L/T tire I am confused as well. I'll look at the tables again to see if it makes more sense as an L/T tire. Thanks.

 

[gaijin]

I have a new to me 2008 LC that came with P265/60/r18 Radial Long Trails. The tires looked and felt low so I looked at the tables provided and my understanding from these tables is the the tires are totally inadequate for this vehicle. The table cuts off at 35psi and the max inflation pressure is 44psi. If I extrapolate the numbers out I get an inflation pressure of 41psi for these tires but I am guessing these values are missing for a reason. I have new 275/70r18 nitto ridge grapplers on order but would appreciate advice on what pressure to run these at until the new tires arrive.

No apology needed. The tire distinctly says P265 so if it is an L/T tire I am confused as well. I'll look at the tables again to see if it makes more sense as an L/T tire. Thanks.

Max inflation on the sidewall does list 44psi, hence some of my confusion. Max load 2271 lbs for what thats worth as well. Maybe I'll get lucky and the new tires will show up at Discount Tires sooner rather than later.

I can't find a product spec for any B.F. Goodrich Long Trail tires in size P265/70R18, so I am going to rely on the info you provided.

If your tires have P265 branded on them and NOT LT265 then they are indeed P-Metric tires. The required Load Limit for P-Metric tires on your 2008 LC is 2,512 pounds. As you already suspect, these tires are NOT suitable for use on your LC. AS AN EMERGENCY MEASURE ONLY UNTIL YOUR NEW TIRES ARRIVE, I recommend inflating these tires to the sidewall max of 44psi. This will only afford you a Load Limit of 2,271 pounds, but it is the best temporary option available. I would suggest avoiding high speeds, heavy loads and "dramatic" driving until you replace with new tires.

Now the good news!

The Nitto Ridge Grapplers in size LT275/70R18 E 125/122Q appear to be a very nice tire and well suited to your LC. I have no personal experience with that size, but if you are confident it will fit and function as it should based on the experience of others, then it should do well. The Recommended Cold Tire Inflation Pressure for the LT275/70R18 E 125/122Q Nitto Ridge Grappler tires on your 2008 LC is 41psi Front/Rear.

Just one word of caution: The Q Speed Rating of the Ridge Grappler tires limits their use to <99mph. Certainly not an issue off road, but something you should be aware of on the highway.

Hope you can replace your old tires soon.

HTH

 

[gaijin]

Gaijin,
i recently installed a set of Yokohama g015 LT 315/70/17 with max 65 psi on the wall, on my GX 460. The tire shop is telling me that the pressure should be what Lexus wrote on the door jam. 32/ 32 front and rear. Are they correct ??
Thank you for your wisdom.

I have all the background data I need for Land Cruisers, but not for GX 460's. In order to answer your question I will need the following info:

1. A picture of the door placard containing all the tire load info.

Failing that I will need the following info from that door placard:

1. GVWR
2. Front axle GAWR
3. Rear axle GAWR
4. Stock tire size exactly as it appears on the placard
5. Recommended inflation pressure(s) for both front and rear

For the sake of expediency, I can, however, make some assumptions based on the following:

Stock tire size is P265/60R18 109H
Recommended Cold Tire Inflation Pressure is 32psi F/R

If these assumptions are NOT correct, then please correct me and ignorethe following:

The Recommended Cold Tire Inflation Pressure for the Yokohama Geolandar A/T G015 LT315/70R17 121S is 35psi.

NOTE 1: 35psi is the minimum recommended tire pressure for these tires on ANY vehicle. At 35psi, the Load Limit is 2,535 pounds which is far above the required Load Limit of 1,985 pounds for an LT-Metric tire on your GX460. This means that the tire is way over spec for the vehicle and will probably exhibit a stiff tire "spring rate."

NOTE 2: Obviously I can not confirm that the LT315/70R17 tires will fit and function properly on your vehicle. All I am recommending is a safe tire pressure at which to operate on road should you decide to mount this size tire on your GX 460.

HTH

 

[NMNORSSE]

I found some info online saying it is a l/t tire and the p is employed to indicate passenger tread, which is confusing and troubling. The tires are available at discount tire, pep boys and sears and come standard on some trucks. Not sure how they ended up on your LC since the don't meet the weight requirement, as both you and Gaijin noted. If you had some trouble caused by the tires, you could look to whoever sold and installed them even though you aren't the original purchaser. That shop may buy them back and be thankful no one was hurt when the error is pointed out, or at least they'll be more careful next time.

 

[Virgilus11]

I have all the background data I need for Land Cruisers, but not for GX 460's. In order to answer your question I will need the following info:

1. A picture of the door placard containing all the tire load info.

Failing that I will need the following info from that door placard:

1. GVWR
2. Front axle GAWR
3. Rear axle GAWR
4. Stock tire size exactly as it appears on the placard
5. Recommended inflation pressure(s) for both front and rear

For the sake of expediency, I can, however, make some assumptions based on the following:

Stock tire size is P265/60R18 109H
Recommended Cold Tire Inflation Pressure is 32psi F/R

If these assumptions are NOT correct, then please correct me and ignorethe following:

The Recommended Cold Tire Inflation Pressure for the Yokohama Geolandar A/T G015 LT315/70R17 121S is 35psi.

NOTE 1: 35psi is the minimum recommended tire pressure for these tires on ANY vehicle. At 35psi, the Load Limit is 2,535 pounds which is far above the required Load Limit of 1,985 pounds for an LT-Metric tire on your GX460. This means that the tire is way over spec for the vehicle and will probably exhibit a stiff tire "spring rate."

NOTE 2: Obviously I can not confirm that the LT315/70R17 tires will fit and function properly on your vehicle. All I am recommending is a safe tire pressure at which to operate on road should you decide to mount this size tire on your GX 460.

HTH

Thank you . All your info and assumptions about the GX where correct. I inflate the tires from 32 to 35 this morning and coming from a 34"KO2 tire, these tires feel more comfortable and track better on the highway. With the 4,56 gears the truck runs now, within 50 rpm's from original tires was running.
I have 2.5" lift ARB all around and and a body mount chop. The tire is touching the inner fender plastic at rear only, at full compression only. I am going to improve on that with a body lift from Toytec and a bump stop spacer that is been ordered already. I don't go off road and in normal driving the tires are not touching anything. If I where to go off road I would consider swapping back the 34".
Thank you for your time, knowledge and suggestions.

 

[LostRoad]

I can't find a product spec for any B.F. Goodrich Long Trail tires in size P265/70R18, so I am going to rely on the info you provided.

If your tires have P265 branded on them and NOT LT265 then they are indeed P-Metric tires. The required Load Limit for P-Metric tires on your 2008 LC is 2,512 pounds. As you already suspect, these tires are NOT suitable for use on your LC. AS AN EMERGENCY MEASURE ONLY UNTIL YOUR NEW TIRES ARRIVE, I recommend inflating these tires to the sidewall max of 44psi. This will only afford you a Load Limit of 2,271 pounds, but it is the best temporary option available. I would suggest avoiding high speeds, heavy loads and "dramatic" driving until you replace with new tires.

Now the good news!

The Nitto Ridge Grapplers in size LT275/70R18 E 125/122Q appear to be a very nice tire and well suited to your LC. I have no personal experience with that size, but if you are confident it will fit and function as it should based on the experience of others, then it should do well. The Recommended Cold Tire Inflation Pressure for the LT275/70R18 E 125/122Q Nitto Ridge Grappler tires on your 2008 LC is 41psi Front/Rear.

Just one word of caution: The Q Speed Rating of the Ridge Grappler tires limits their use to <99mph. Certainly not an issue off road, but something you should be aware of on the highway.

Hope you can replace your old tires soon.

HTH

The tire is a 265/60r18 rather than a 70. Not that that changes anything since it is below the load limit for this vehicle anyways. Thank you very much for your advice and recommendations for both the current tires and the new ones. Also, thank you for pointing out the Q speed rating as I had not even thought to check that.

@NMNORSSE, Interesting that there is conflicting info out there as to them being P or LT tires. Confusing at the very least. Not sure who put the wrong tires on this vehicle but will certainly be contacting the dealer that I purchased it through to let them know. I honestly doubt they would fess up to putting them on even if they did.

 

[gaijin]

The tire is a 265/60r18 rather than a 70. Not that that changes anything since it is below the load limit for this vehicle anyways. Thank you very much for your advice and recommendations for both the current tires and the new ones. Also, thank you for pointing out the Q speed rating as I had not even thought to check that.

Yes, my typo, I did check for 265/60R18 but could not find any info published by BFG for that size/model tire. You are correct, that changes nothing.

You're welcome. Always glad to help out.

 

[TexasTundra]

Yes, my typo, I did check for 265/60R18 but could not find any info published by BFG for that size/model tire. You are correct, that changes nothing.

You're welcome. Always glad to help out.

Gaijin, first of all, I like how you even put your tire pressure in your signature bar. Never seen that before.

Second, how does armor affect recommended pressure? For example, a fully armored 200 on 285/75R17 BFG KM2s?

Thanks in advance.