Tire Pressure BFG KO2's

[kcobourn]

Toyota/Lexus engineered the suspension systems on the two vehicles to provide optimum safe performance with different tire spring rates (i.e. tire pressures). Different vehicles, different suspensions, different engineering considerations from the manufacturer - simple as that.

HTH

@gaijin having spent hours reading through various posts I’m now curious to see what
your POV is given a test I ran?

TL;DR @gaijin with my 2016 LC200 am running the At3 LT285/65R18 at LX570 PSI (37.5-ish). This is workable from a comfort POV + passed chalk test. Setting RCTIP 41-43 PSI is trash I hate it and want to burn these damn things ($2,300 down the tubes!). Do you have any further evidence why this is dangerous? And why / how do suspension systems effect PSI? Same truck same weight isn’t that the measure GVWR?

A more detailed description (@TeCKis300 I’m leaning in on your opinion based on my personal experiences … please also take a look)

Setup - I have a LC200. It’s stock with 3rd row pulled (maybe 100 pounds less weight) with a set of Toyo At3 LT285/65R18 E loads.

Phase 1: Awful trash I hate this thing. For a few days ran them at 41-ish PSI. As you mentioned they’re fine on smooth roads. In bumpy, urban, and neighborhood roads they feel jittery as hell. NOTE Toyo customer service told me 43 PSI when I called to ask about a return - yikes!

This is not good - it’s the wifey mobile and she’s complaining.

Phase 2: Burning my Monday night in the ‘mud information pile. My options are 1) swap for ISO metric stock sized At3s or 2) try to correct the issue with lower “underinflated” values.

Phase 3: Before selling the 200-series let’s head-to-head with my 2006 LC100. Valid because it runs with the same AT3s sized at LT270/70R18 E loads @ 35 PSI (please correct me if these aren’t the right pressures!).

Results? I’ve wasted my money. The 2006 is perfect the 2016s suck with E loads screw this I’ll just get a highway tire.

Phase 4: Challenge the ‘mud RCTIP and Toyo customer support gods!

If it’s about weight, and despite the varied suspension AHC vs standard springs/shocks, then why can’t it be valid to consider using the LX570 specs?

What if it isn’t a literal, “only this or you’re going to die and kill your family in a terrible pothole” set of standards to apply? What if it’s true that corporate enterprises and their standards are designed to ensure “safety” as measured by exposure to lawsuits?

Phase 5: Screw it I set my LC200 COLD pressures to 37.5-ish.

Concerned about the dreaded under-inflation my first step was a chalk test to confirm the tread is definitely in full contact because all chalk across all treads were scrubbed after a .75 mile drive down our neighborhood hills.

Chalk test, passed.

What about PSI levels increasing due to excess heat??? Nope. Went to 40-41 with some serous highway speeds under speed rating and over “go to jail”.

My next test was subjective … does the truck behave like it’s on too much caffeine (if you’re a southpark fan think of the character “tweak”!!)….

NO the truck felt reasonably planted and the suspension felt like it actually absorbed the bumpy road instead of feeling like it’s just bouncing across the surface.

Phase 6: Return to ‘mud, report results. Suit up with flame retardant!

In conclusion I’m either going to break the RCTIP standards and join the death cult

Or I’m just going back to ISO and run stock sizing.

 

[gaijin]

@gaijin having spent hours reading through various posts I’m now curious to see what
your POV is given a test I ran?

TL;DR @gaijin with my 2016 LC200 am running the At3 LT285/65R18 at LX570 PSI (37.5-ish). This is workable from a comfort POV + passed chalk test. Setting RTCIP 41-43 PSI is trash I hate it and want to burn these damn things ($2,300 down the tubes!). Do you have any further evidence why this is dangerous? And why / how do suspension systems effect PSI? Same truck same weight isn’t that the measure GVWR?

A more detailed description (@TeCKis300 I’m leaning in on your opinion based on my personal experiences … please also take a look)

Setup - I have a LC200. It’s stock with 3rd row pulled (maybe 100 pounds less weight) with a set of Toyo At3 LT285/65R18 E loads.

Phase 1: Awful trash I hate this thing. For a few days ran them at 41-ish PSI. As you mentioned they’re fine on smooth roads. In bumpy, urban, and neighborhood roads they feel jittery as hell. NOTE Toyo customer service told me 43 PSI when I called to ask about a return - yikes!

This is not good - it’s the wifey mobile and she’s complaining.

Phase 2: Burning my Monday night in the ‘mud information pile. My options are 1) swap for ISO metric stock sized At3s or 2) try to correct the issue with lower “underinflated” values per RTCIP tables.

Phase 3: Before selling the 200-series let’s head-to-head with my 2006 LC100. Valid because it runs with the same AT3s sized at LT270/70R18 E loads @ 35 PSI (please correct me if these aren’t the right pressures!).

Results? I’ve wasted my money. The 2006 is perfect the 2016s suck with E loads screw this I’ll just get a highway tire.

Phase 4: Challenge the ‘mud RCTIP and Toyo customer support gods!

If it’s about weight, and despite the varied suspension AHC vs standard springs/shocks, then why can’t it be valid to consider using the LX570 specs?

What if RTCIP isn’t a literal, “only this or you’re going to die and kill your family in a terrible pothole” set of standards to apply? What if it’s true that corporate enterprises and their standards are designed to ensure “safety” as measured by exposure to lawsuits?

Phase 5: Screw it I set my LC200 COLD pressures to 37.5-ish.

Concerned about the dreaded under-inflation my first step was a chalk test to confirm the tread is definitely in full contact because all chalk across all treads were scrubbed after a .75 mile drive down our neighborhood hills.

Chalk test, passed.

What about PSI levels increasing due to excess heat??? Nope. Went to 40-41 with some serous highway speeds under speed rating and over “go to jail”.

My next test was subjective … does the truck behave like it’s on too much caffeine (if you’re a southpark fan think of the character “tweak”!!)….

NO the truck felt reasonably planted and the suspension felt like it actually absorbed the bumpy road instead of feeling like it’s just bouncing across the surface.

Phase 6: Return to ‘mud, report results. Suit up with flame retardant!

In conclusion I’m either going to break the RTCIP standards and join the death cult

Or I’m just going back to ISO and run stock sizing.

For the LT285/65R18 tires:

35psi is the absolute minimum cold tire inflation pressure required to meet the design parameters of the TIRE, as defined by the TRA (Tire and Rim Association), irrespective of vehicle.

37psi is the RCTIP (Recommended Cold Tire Inflation Pressure) to meet the design criteria for the LX570 as defined by Toyota.

42psi is the RCTIP to meet the design criteria for the LC200 as defined by Toyota.

How you interpret/implement these criteria is entirely up to you. It's the same as if you were running a totally stock vehicle, with the tires that came on it from the factory, and looked at the Vehicle Information Placard that indicates 33psi as the RCTIP for your LC200, and decided to run a different pressure based on your own experience for your use case.

It's up to you what cold tire pressure you use.

HTH

 

[TeCKis300]

For the LT285/65R18 tires:

35psi is the absolute minimum cold tire inflation pressure required to meet the design parameters of the TIRE, as defined by the TRA (Tire and Rim Association), irrespective of vehicle.

37psi is the RCTIP (Recommended Cold Tire Inflation Pressure) to meet the design criteria for the LX570 as defined by Toyota.

42psi is the RCTIP to meet the design criteria for the LC200 as defined by Toyota.

How you interpret/implement these criteria is entirely up to you. It's the same as if you were running a totally stock vehicle, with the tires that came on it from the factory, and looked at the Vehicle Information Placard that indicates 33psi as the RCTIP for your LC200, and decided to run a different pressure based on your own experience for your use case.

It's up to you what cold tire pressure you use.

HTH

Cross posting here too as this really needs more visibility. RCTIP is not the be all end all, and may actually be misleading in situations.

Tire Pressure recommendation

forum.ih8mud.com

We've been debating this for years. I'm not going to change your mind even as you get feedback that your methodology is flawed. Don't get me wrong, it's still good as a first level approximation. Which then needs further cross-checking. As the hive mind here is finding out, it often doesn't pass real world testing from enough people now, that you should take it to improve on your recommendations. The over-inflation in a number of sizes is outright dangerous as many LCs with stock suspensions cannot outright handle the sidewall spring rates at these pressures. Leading to brittle and skittish performance down the freeway. That is a loss of traction and safety that you're promoting with these RCTIP recommendations.

Food for thought:

35PSI is not some magic minimum pressure for LTs. The TRA handbook only serves as a "standardizing body" whose "primary purpose is to establish and promulgate interchangeability standards". It does NOT dictate design or requirement standards. The fact that the tables stop at 35PSI doesn't mean anything, and only speaks to where their focus lies - load handling of LT tires whose primary use is for heavy trucks. Not necessarily for enthusiasts that choose these tires for adventure and durability. I can and do run my tires depending on use case at less then 35PSI, because the physical world continues on even where a reference table stops.

I'd encourage everyone to re-visit and cross check their inflation pressures. Start with RCTIP. Balance that with other cross check methodologies. Every model tire, even in same sizes, behaves differently and may require further tailoring.

@AnyMal had some great points.

 

[MCtree]

Glad to!

The RCTIP for those LT275/70R/18 tires on your LC200 is (indeed) 41psi F/R.

Happy Thanksgiving!

@gaijin,
Having recently gotten this tire in 275/70/r18 I dutifully filled it to 41 as prescribed by you.

But I’m curious as to why an LC requires more pressure than an LX for the same size. Is it a weight difference in the two trucks?
(And if so, do mods come in to play in the calculations?)

Edit:
Never mind. I should have read the thread all the way through. I see you answered my question in post 74.
Sorry and thanks for the explanation from the past!

 

[TeCKis300]

@gaijin,
Having recently gotten this tire in 275/70/r18 I dutifully filled it to 41 as prescribed by you.

But I’m curious as to why an LC requires more pressure than an LX for the same size. Is it a weight difference in the two trucks?
(And if so, do mods come in to play in the calculations?)

Edit:
Never mind. I should have read the thread all the way through. I see you answered my question in post 74.
Sorry and thanks for the explanation from the past!

That's a great question isn't it? Especially as the LX is the one that has a higher curb weight by 300-500lbs.

RCTIP is flawed.

 

[Reckless]

I'm running 61 psi on my 17" DT KO2s. Much more comfortable than 40psi. From my non scientific data I think 48-52 psi is probably the most comfortable but the 61 psi adds considerable height to the tire.

 

[MCtree]

That's a great question isn't it? Especially as the LX is the one that has a higher curb weight by 300-500lbs.

RCTIP is flawed.

Oh no you don’t!
I’m not getting dragged into your two’s squabble.

But you do make me think; if the reason that the LX requires less pressure in its tires is because if the way they, Toyota, set up the suspension, does the pressure requirement change once we alter the factory suspension?
Or if we add weight?

 

[TeCKis300]

Oh no you don’t!
I’m not getting dragged into your two’s squabble.

But you do make me think; if the reason that the LX requires less pressure in its tires is because if the way they, Toyota, set up the suspension, does the pressure requirement change once we alter the factory suspension?
Or if we add weight?

No dragging and just appealing to common sense as those are reasonable questions.

When is the last time there has been anything about needing to change tire pressure when changing the suspension? The Guidelines for the Application of Load and Inflation Tables makes zero mention of suspension. It also makes zero mention of ride quality and handling. No one upgrading suspensions has said I should adjust the tire pressure after lift. It's not a thing and was contrived as a basis for the J201.

The answer is simpler in that the 33 PSI was a good balance between ride, handling, and met (or exceeded) the requirement for tire load support from the factory. With the LC, 33 PSI exceeded the necessary tire load support of the tires but probably was good from a ride and handling perspective. There a lot of tire load margin in that 33 psi. But there's also a balance of contributing factors which is why derived pressures aren't singularly about load.

To your question on weight - generally the factory inflation has tire load margin and is good for the full spec'd capacity. There are exceptions like the 21" equipped LX570 that also recommends 33 PSI, with the caveat in the manual that pressures should be raised if towing for example. If you exceed capacities like many of us do, you may very well need to increase pressures for weight. Best direct way is to get on a CAT scale and then cross reference the axle load to the above linked reference for your tire size. There's other approximations to do this too.

 

[Tex68w]

I had my set of KO2's replaced under warranty today with around 10K miles on them. I had a wobble from 55-75 mph that would not go away no matter how many times Discount Tire Road Force balanced them. I took my truck in to two different auto/off-road shops this morning to have the front end looked over and the alignment checked and everything was solid. No drive shaft, UCA, CV, or alignment issues found. They touched a wrench on most everything in front of the front doors without finding a culprit. If a drive shaft is out of balance it'll usually subside after letting off of the accelerator and an alignment issue is usually noticeable at most speeds consistently, neither of which were the case. I haven't hit anything and no one else has driven the vehicle.

The tires are 285/75/17 BFG KO2's, the wheels are the Noman Arvo 502's in a 17x8.5" and they had upwards of 12-13 oz of strip weights on a few of them which is absurd. I took it in to three different Discount Tire locations on five different occasions since late April for this complaint over the last 3K miles and each time the issue was still present after they "rebalanced" them. With 17-20 year old kids working in the shop I am pretty certain they simply threw the wheel on the machine and just added weight to what was already on there each time leading to the insane amount of weight present on a few of the wheels. Today the manager of the store personally broke the tires down and started all over with the same outcome, it was at that point that I asked that they replace them under warranty and they did. I sat around for five hours to wait for the replacement tires to arrive from the other side of the city to replaced today instead of burning yet another day dealing with this. With us departing Friday morning for Colorado I had no choice but to get to the bottom of this asap as there was no way I was willing to drive it like that over 2500 miles at highway speeds.

Discount initially wanted to blame the wheels but if that were the case I would expect that to have been evident from day one and not something that cropped over the first 5-10K miles like it did. I called Nomad/Raceline to inquire if they had reports of any other issues and they have not heard of any, they also agreed that it would have been noticeable from the very start if it were the wheels. For now things are much better (at least over my one hour drive home) and I have a new set of rubber to roll on (first big win in forever), but I have my fingers crossed that the issue doesn't show back up on our trip. If it does I am sending the misses home with the folks after the week and I'll head to Slee lol.

 

[artwerks]

Thanks for being such a great resource!

What is the recommended tire pressure for a LT295/65/18, 127/124P, load range E?

 

[gaijin]

Thanks for being such a great resource!

What is the recommended tire pressure for a LT295/65/18, 127/124P, load range E?

The RCTIP for an LT295/65R18 tire on your 2017 LC200 is 39psi F/R.

HTH

 

[PD753]

2015 200 series
KO2 275/60/R20 119/116s
Load Range D

Installer told me 41 PSI for all 4 but I have no idea. Seems a teeny bit low to me.

 

[PD753]

2015 200 series
KO2 275/60/R20 119/116s
Load Range D

Installer told me 41 PSI for all 4 but I have no idea. Seems a teeny bit low to me.

Sorry… to clarify….200 series Toyota LC

 

[gaijin]

2015 200 series
KO2 275/60/R20 119/116s
Load Range D

Installer told me 41 PSI for all 4 but I have no idea. Seems a teeny bit low to me.

Sorry… to clarify….200 series Toyota LC
View attachment 3377190

The RCTIP (Recommended Cold Tire Inflation Pressure) for those LT275/60R20 tires on your LC200 is 45psi F/R.

Be sure to adjust your tire pressures when the tires are cold (i.e. not having been driven on for at least 4 hours - preferably overnight), and reset your TPWS (Tire Pressure Warning System) after setting the new pressures.

HTH

 

[PD753]

The RCTIP (Recommended Cold Tire Inflation Pressure) for those LT275/60R20 tires on your LC200 is 45psi F/R.

Be sure to adjust your tire pressures when the tires are cold (i.e. not having been driven on for at least 4 hours - preferably overnight), and reset your TPWS (Tire Pressure Warning System) after setting the new pressures.

HTH

Thank you kindly!!

 

[gaijin]

Thank you kindly!!

You're very welcome.

 

[MCtree]

I had my set of KO2's replaced under warranty today with around 10K miles on them. I had a wobble from 55-75 mph that would not go away no matter how many times Discount Tire Road Force balanced them. I took my truck in to two different auto/off-road shops this morning to have the front end looked over and the alignment checked and everything was solid. No drive shaft, UCA, CV, or alignment issues found. They touched a wrench on most everything in front of the front doors without finding a culprit. If a drive shaft is out of balance it'll usually subside after letting off of the accelerator and an alignment issue is usually noticeable at most speeds consistently, neither of which were the case. I haven't hit anything and no one else has driven the vehicle.

The tires are 285/75/17 BFG KO2's, the wheels are the Noman Arvo 502's in a 17x8.5" and they had upwards of 12-13 oz of strip weights on a few of them which is absurd. I took it in to three different Discount Tire locations on five different occasions since late April for this complaint over the last 3K miles and each time the issue was still present after they "rebalanced" them. With 17-20 year old kids working in the shop I am pretty certain they simply threw the wheel on the machine and just added weight to what was already on there each time leading to the insane amount of weight present on a few of the wheels. Today the manager of the store personally broke the tires down and started all over with the same outcome, it was at that point that I asked that they replace them under warranty and they did. I sat around for five hours to wait for the replacement tires to arrive from the other side of the city to replaced today instead of burning yet another day dealing with this. With us departing Friday morning for Colorado I had no choice but to get to the bottom of this asap as there was no way I was willing to drive it like that over 2500 miles at highway speeds.

Discount initially wanted to blame the wheels but if that were the case I would expect that to have been evident from day one and not something that cropped over the first 5-10K miles like it did. I called Nomad/Raceline to inquire if they had reports of any other issues and they have not heard of any, they also agreed that it would have been noticeable from the very start if it were the wheels. For now things are much better (at least over my one hour drive home) and I have a new set of rubber to roll on (first big win in forever), but I have my fingers crossed that the issue doesn't show back up on our trip. If it does I am sending the misses home with the folks after the week and I'll head to Slee lol.

Do the new tires have a bunch of weights added?
Or were they balanced with a normal amount?

 

[Tex68w]

Do the new tires have a bunch of weights added?
Or were they balanced with a normal amount?

Most of the new ones have around 6oz., far less than the previous set. They chalked it up to tires with a possible manufacturing defect and just swapped them out under warranty on BFG's dime, but one of the tech's suggested that maybe that particular wheel and tire combo simply doesn't play well together, so who knows. I am just grateful to have been given a brand new set, it basically bought me 11K miles of free rubber.

 

[gaijin]

Most of the new ones have around 6oz., far less than the previous set. They chalked it up to tires with a possible manufacturing defect and just swapped them out under warranty on BFG's dime, but one of the tech's suggested that maybe that particular wheel and tire combo simply doesn't play well together, so who knows. I am just grateful to have been given a brand new set, it basically bought me 11K miles of free rubber.

I have no idea if this could have been the case with your tires, but maybe worth mentioning.

There is a specific Toyota Only wheel mounting fixture used on the balancing machines to affix a 5 x 150 Toyota wheel to the machine. I'm unclear about the exact "magic" behind this fixture, but I believe it has to do with our wheels being hub-centric and not lug centric. I've heard stories (I know, real solid evidence, right?) that no matter how carefully a wheel/tire combo is balanced with the wrong wheel fixture, the results will not be reliable.

These stories come from Discount Tire and my experience with them.

Maybe worth mentioning about the Toyota specific wheel fixture next time getting wheel balancing done.

Just my $0.02.

HTH

ETA: Maybe this Toyota TSB has more clues about what I'm trying to convey: Toyota TSB SU002-96

It talks about the use of a "centering cone" to center the wheel as opposed to using the lug holes.

 

[Tex68w]

I have no idea if this could have been the case with your tires, but maybe worth mentioning.

There is a specific Toyota Only wheel mounting fixture used on the balancing machines to affix a 5 x 150 Toyota wheel to the machine. I'm unclear about the exact "magic" behind this fixture, but I believe it has to do with our wheels being hub-centric and not lug centric. I've heard stories (I know, real solid evidence, right?) that no matter how carefully a wheel/tire combo is balanced with the wrong wheel fixture, the results will not be reliable.

These stories come from Discount Tire and my experience with them.

Maybe worth mentioning about the Toyota specific wheel fixture next time getting wheel balancing done.

Just my $0.02.

HTH

Well the manager that was trying to work them out mentioned that he thought one of the wheels had a smaller bore size than the others but I ran calipers on them and that's not the case, so who knows. All I know is that they ran perfectly well for 5-6K miles then they re-balanced them and it was never the same, it all went to hell and they just kept throwing weight at the problem making it worse and worse each visit. At the end of the day I got new tires for no money out of pocket and things are better, hopefully they stay that way.