Tire Pressure recommendation (3 Viewers)

[gaijin]

Wait! What’s up with different front and rear pressures here? Is that specific to the 2008? I have a 2009 LC with these tires that I run at 46 psi F/R per earlier posts and other threads.

The 2008 LC200 is the only model year that was delivered with Recommended Cold Tire Inflation Pressures for the stock P285/60R18 tires of 32psi Front / 34psi Rear. From 2009 on the Recomended Cold Tire Inflation Pressure is 33psi Front/Rear. 46psi F/R is what I recommended for these tires on model years other than 2008 and is what you should be running.

HTH

 

[canyonrider]

Awesome, thanks. Killing it per usual, really appreciate the info you share here.

 

[Chrisleduc1]

What is proper pressure for the Michelin Defender LTX M/S 285/60/20 installed on an ‘18LX ??

Thanks !!

Ehh - That size is NOT correct, I forgot to mention that this is an LT tire !! LT285/60/20

 

[gaijin]

What is proper pressure for the Michelin Defender LTX M/S 285/60/20 installed on an ‘18LX ??

Thanks !!

The Recommended Cold Tire Inflation Pressure for the LT285/60R20/E 125/122R Michelin Defender LTX M/S tires on your 2018 LX570 is 38psi Front/Rear.

HTH

 

[gaijin]

Ehh - That size is NOT correct, I forgot to mention that this is an LT tire !! LT285/60/20

No problem - I read your mind and calc'd for the correct tire size.

HTH

 

[Markuson]

The Recommended Cold Tire Inflation Pressure for the LT285/70R18 tires on your LC200 is 38psi F/R.

HYPOTHETICALLY, and I don't like hypotheticals, if you want to know how much more load each of these new tires MIGHT be able to handle at higher than recommended pressures, then one MIGHT consult the following chart:

Stock LC200 / 38psi / 2309 lbs/tire
172 pounds over stock LC200 / 39psi / 2352 lbs/tire
344 pounds over stock LC200 / 40psi / 2395 lbs/tire
508 pounds over stock LC200 / 41psi / 2436 lbs/tire
672 pounds over stock LC200 / 42psi / 2477 lbs/tire
836 pounds over stock LC200 / 43psi / 2518 lbs/tire

I DO NOT RECOMMEND ANY OF THE PRESSURES SHOWN IN THIS CHART WHICH DIFFER FROM THE RECOMMENDED COLD TIRE INFLATION PRESSURE OF 38psi.

Hypothetically, of course.

HTH

Good question.

My 200 is as high as 8200k once my wife and I are aboard and full loaded, fueled.
Hmmm...

35x12.5x17 Ridge Grapplers...which Gaijin tells me should be 33.
But that that weight? Hmmm...

Any advice, oh sage?

 

[gaijin]

Good question.

My 200 is as high as 8200k once my wife and I are aboard and full loaded, fueled.
Hmmm...

35x12.5x17 Ridge Grapplers...which Gaijin tells me should be 33.
But that that weight? Hmmm...

Any advice, oh sage?

This is the kind of conjecture I was hoping to avoid ... If by, "8200k" you mean 8,200 pounds, then you are 815 pounds over the 7385LB GVWR for your truck. I know, I know - bigger springs, bigger shocks, bigger tires, etc. all should increase the GVWR, so what's the problem? It's a sound argument, but I can't support it with data. That's my hangup.

So ... strictly speaking from a tire perspective, IF you want to THEORETICALLY increase the GVWR of your truck from 7385LB to 8200LB, you would need to increase the Load Limit; but to what value?

Stock GVWR of 7385LB specs a Load Limit of 2286LB/tire. 2286 x 4 = 9144LB which is the total Load Limit of all 4 tires. This is approximately 1.24 times more than the GVWR (9144/7385=1.24). IF this ratio holds, then to support a THEORETICAL GVWR of 8200LB, we would need a total Load Limit of 8200 X 1.24 = 10168LB -or- 10168 / 4 = 2542LB/tire. For your 35X12.50R17LT tires, this would require a Cold Tire Inflation Pressure of 39psi which would yield a Load Limit of 2581LB/tire. 38psi would get you close with a Load Limit of 2537LB/tire.

THEORETICALLY.

HTH

 

[Markuson]

This is the kind of conjecture I was hoping to avoid ... If by, "8200k" you mean 8,200 pounds, then you are 815 pounds over the 7385LB GVWR for your truck. I know, I know - bigger springs, bigger shocks, bigger tires, etc. all should increase the GVWR, so what's the problem? It's a sound argument, but I can't support it with data. That's my hangup.

So ... strictly speaking from a tire perspective, IF you want to THEORETICALLY increase the GVWR of your truck from 7385LB to 8200LB, you would need to increase the Load Limit; but to what value?

Stock GVWR of 7385LB specs a Load Limit of 2286LB/tire. 2286 x 4 = 9144LB which is the total Load Limit of all 4 tires. This is approximately 1.24 times more than the GVWR (9144/7385=1.24). IF this ratio holds, then to support a THEORETICAL GVWR of 8200LB, we would need a total Load Limit of 8200 X 1.24 = 10168LB -or- 10168 / 4 = 2542LB/tire. For your 35X12.50R17LT tires, this would require a Cold Tire Inflation Pressure of 39psi which would yield a Load Limit of 2581LB/tire. 38psi would get you close with a Load Limit of 2537LB/tire.

THEORETICALLY.

HTH

Thank you for the careful thought, gaijin. Much appreciated.

Without my fat carcass and my wife...fully loaded would be closer to 7800...but still very heavy.

 

[Markuson]

Not an argument...but just a weight consideration I think about before getting too worried.

-With seating for 7 people...and assuming an average of five adults at 175 and two kids at 50... That's 975lbs of additional weight without any luggage. In addition, this assumes the presence of the third row seat with its own weight, of course.

In my family of taller, big guys...7 people would tip the scales closer to 1200-1300 lbs of humans.

It seems to me that if it was that critical...they would not present the truck as safely seating 7 people.

I wonder what you thing of this? In my mind...my extra weight plus 1 passenger and driver is sort of like simply running with butts in every seat.

Make sense?

 

[gaijin]

Not an argument...but just a weight consideration I think about before getting too worried.

-With seating for 7 people...and assuming an average of five adults at 175 and two kids at 50... That's 975lbs of additional weight without any luggage. In addition, this assumes the presence of the third row seat with its own weight, of course.

In my family of taller, big guys...7 people would tip the scales closer to 1200-1300 lbs of humans.

It seems to me that if it was that critical...they would not present the truck as safely seating 7 people.

I wonder what you thing of this? In my mind...my extra weight plus 1 passenger and driver is sort of like simply running with butts in every seat.

Make sense?

You really should weigh your truck at a commercial scale. What is not subject to marketing whimsy is the GVWR - 7,385 pounds. Yes, it's critical. If it were not, would Toyota go to the trouble of requiring a sticker like this ...

... reminding us that the Load Carrying Capacity of our vehicle has been reduced by 17 pounds because the port installed a rear entertainment system?

Add an extra battery? Reduce the Load Carrying Capacity by 60 pounds or so. Add a bumper? Add drawers? You get the idea. So, even if you keep the total vehicle weight under the GVWR of 7,385 pounds, you may have accessorized yourself out of being capable of carrying any passengers

The Owner's Manual does a pretty good job of specifying the exact weights for load, but add any additional "stuff" and that capacity diminishes accordingly.

Hey - you asked!

HTH

 

[TonyP]

Change suspension, GVWR is (essentially) increased, as it's partially a product of suspension.
Axle rating is significantly more and that's what to be mindful of, that and tire rating.

 

[Markuson]

You really should weigh your truck at a commercial scale. What is not subject to marketing whimsy is the GVWR - 7,385 pounds. Yes, it's critical. If it were not, would Toyota go to the trouble of requiring a sticker like this ...

... reminding us that the Load Carrying Capacity of our vehicle has been reduced by 17 pounds because the port installed a rear entertainment system?

Add an extra battery? Reduce the Load Carrying Capacity by 60 pounds or so. Add a bumper? Add drawers? You get the idea. So, even if you keep the total vehicle weight under the GVWR of 7,385 pounds, you may have accessorized yourself out of being capable of carrying any passengers

The Owner's Manual does a pretty good job of specifying the exact weights for load, but add any additional "stuff" and that capacity diminishes accordingly.

Hey - you asked!

HTH

I used a CAT scale, so it was definitely accurate. What I screwed up on was that I did the entire vehicle, rather than front/back weights. I'll do that soon.

I'm not suggesting carrying 6 passengers, but rather simply mentioning it since Toyota provides the seating. My assumption is that they must build in enough leeway in order to encourage seating for 7.

My rationale is that I'm basically carrying 7 passenger's weight equivalent in gear, etc. or close to it. I agree that adding 7 passengers in addition would be really pushing it...but then I don't even have third row any more to seat 7.

 

[earthsurfer]

You need look no further than the sticker on your door jam - it will show the Recommended Cold Tire Inflation Pressures for your stock P285/60R18 tires as 32psi Front / 34psi Rear. This calcs out to thge pressures I recommended for you - 45psi Front / 47psi Rear.

Why did America's Tires put down the wrong tire pressure for your rears? You'll have to ask them why they made that mistake.

I'm more curious how you managed to run those tires at 33psi F/R for 55 thousand miles when you had a dramatically different recommended pressure from Discount Tire (45psi F/R) AND a door placard that had different pressures for front and rear.

Glad you are concerned now, and glad we could get you back in the safe zone for pressure.

HTH

You need look no further than the sticker on your door jam - it will show the Recommended Cold Tire Inflation Pressures for your stock P285/60R18 tires as 32psi Front / 34psi Rear. This calcs out to thge pressures I recommended for you - 45psi Front / 47psi Rear.

Why did America's Tires put down the wrong tire pressure for your rears? You'll have to ask them why they made that mistake.

I'm more curious how you managed to run those tires at 33psi F/R for 55 thousand miles when you had a dramatically different recommended pressure from Discount Tire (45psi F/R) AND a door placard that had different pressures for front and rear.

Glad you are concerned now, and glad we could get you back in the safe zone for pressure.

HTH

My 2008 LC says 33 psi front and rear on the door placard. That's why I've been running them at that pressure. As for the pressure recommended on the receipt from America's Tires, I discounted it based on a prior purchase experience where an America's Tires employee
argued that he was correct in inflating my tires to 50psi which was the max pressure listed on that tire's sidewall. Not very scientific, I concede, but I decided I'd go with Toyota's recommendation over America's Tires as a result. This current set of LT tires is the fourth set of LT tires that I have run at the pressure indicated on the door placard. 2 sets with my old 60 and now 2 with my 200. I think the total mileage I've clocked is over 150,000 miles with no issues.

 

[gaijin]

I used a CAT scale, so it was definitely accurate. What I screwed up on was that I did the entire vehicle, rather than front/back weights. I'll do that soon.

I'm not suggesting carrying 6 passengers, but rather simply mentioning it since Toyota provides the seating. My assumption is that they must build in enough leeway in order to encourage seating for 7.

My rationale is that I'm basically carrying 7 passenger's weight equivalent in gear, etc. or close to it. I agree that adding 7 passengers in addition would be really pushing it...but then I don't even have third row any more to seat 7.

Here's what's in the Owner's Manual:

It's pretty straightforward - as far as load is concerned, in a stock truck, you have 1,295 pounds to play with. Everything you add counts against the load. Seating is provided for 8 persons, but how many you can safely carry is based on how much other load you have. Everything you have added to your truck gets subtracted from the 1,295 pounds.

How much you think you have increased the Load Carrying Capacity of your truck with suspension, tires, etc, is entirely on you.

HTH

 

[gaijin]

My 2008 LC says 33 psi front and rear on the door placard. That's why I've been running them at that pressure. As for the pressure recommended on the receipt from America's Tires, I discounted it based on a prior purchase experience where an America's Tires employee
argued that he was correct in inflating my tires to 50psi which was the max pressure listed on that tire's sidewall. Not very scientific, I concede, but I decided I'd go with Toyota's recommendation over America's Tires as a result. This current set of LT tires is the fourth set of LT tires that I have run at the pressure indicated on the door placard. 2 sets with my old 60 and now 2 with my 200. I think the total mileage I've clocked is over 150,000 miles with no issues.

Great! Run whatever pressure you want.

 

[earthsurfer]

Great! Run whatever pressure you want.

LOL

 

[danielb]

I picked up my new '18 last week from the dealer and was somewhat dismayed at the relatively rough ride home on the maiden voyage. Checking the cold pressure the next morning, I found the dealer (or the port) had pumped up each tire to 47 psi. Having viewed various and multiple gaijin posts re psi over the last several lurking months, I quickly put them to the door-sticker recommendation of 33 psi. Rides much better!

So thanks gaijin for all your contribs!

 

[gaijin]

I picked up my new '18 last week from the dealer and was somewhat dismayed at the relatively rough ride home on the maiden voyage. Checking the cold pressure the next morning, I found the dealer (or the port) had pumped up each tire to 47 psi. Having viewed various and multiple gaijin posts re psi over the last several lurking months, I quickly put them to the door-sticker recommendation of 33 psi. Rides much better!

So thanks gaijin for all your contribs!

Always glad to help - thanks for the kind words.

Don't forget to initialize your TPMS now that you have the correct pressure set.

HTH

 

[earthsurfer]

The 2008 LC200 is the only model year that was delivered with Recommended Cold Tire Inflation Pressures for the stock P285/60R18 tires of 32psi Front / 34psi Rear. From 2009 on the Recomended Cold Tire Inflation Pressure is 33psi Front/Rear. 46psi F/R is what I recommended for these tires on model years other than 2008 and is what you should be running.

HTH

This appears to be inaccurate information as my 08 LC says 33psi F/R on the door.

And as to your claim that 46 psi is what one "should" be running...on what basis do you make this claim?

 

[gaijin]

This appears to be inaccurate information as my 08 LC says 33psi F/R on the door.

And as to your claim that 46 psi is what one "should" be running...on what basis do you make this claim?

View attachment 1652506

Good to know. Then for your late model year 2008 you should be running 46psi F/R.

It's not a claim, it's a fact based on the Load Limit/Inflation tables published by the Tire and Rim Association.

You can do a search and find the whole story somewhere, but here are the pertinent steps in determining your Recommended Cold Tire Inflation Pressure:

- Find the TRA Load/Inflation tables for your OEM and new tires (an open source for most of this info is here: https://toyo-arhxo0vh6d1oh9i0c.stac...ication_of_load_inflation_tables_20170203.pdf)

- For your stock P285/60R18 tires @33psi the Load Limit is 2,512 pounds
- Since you are replacing the P-metric tires with LT-metric tires, the required Load Limit must be reduced 10% which is a new Load Limit requirement of 2512/1.1 = 2,284 pounds
- On the Load/Inflation tables for your new LT285/60R18 tires find the pressure that is >2,284 pounds

You will find on the Load/Inflation table that 2,284 pounds falls between 2,250 pounds @45psi and 2,470 pounds @50psi. We can calculate the interim values by determining the amount the Load Limit increases per psi by finding the difference (2470 - 2250 = 220 pounds) dividing that by the 5 pounds between the two values (220 / 5 = 44 pounds per psi). Since 45psi is not enough, add one psi (44 pounds) to yield 2250 + 44 + 2,294 pounds Load Limit @46psi - this is what you should be running.

Less than 46psi and your tires are underinflated and do not have enough Load Limit.

You are free to read through the entire Guidelines for the Application of Load and Inflation Tables I linked to above - it will answer most questions you may have. If you have any other questions, feel free to post them and I'll try to answer them.

HTH