LX 20 to 18/17

[bloc]

Also, I personally believe when considering the forces involved, compared to the stiffening effect of greater tire pressure, stiffer sidewalls do very little to impact things like tire deformation during cornering, at least when talking sidewalls as tall as these. Teckis' 911 with such small aspect ratios may be different.

But my point is that I believe a 40psi P-metric is going to act a lot like a 40psi LT-metric in corners, because the inflation pressure provides such a huge portion of the stiffness of the tire. Obviously different tread compounds and designs will have a large impact on ultimate traction, but I'm referring to the way the tire carcass moves around under the weight of our trucks, which seems to me to be a major factor when thinking about safety.

 

[AnyMal]

So what you are saying is if running <34” then toyota OEM is your only option. I’m not aware of any aftermarket rim in 5x150 that has more then +40, > +35 is extremely limited.

Thats exactly the problem, the Toyota oem is too conservative to plus size on. And the wheel selection is even worse when chasing an OE scrub (which is no good IMO). Theres a lot of spacers here on MUD for that reason with OE wheels. Theres just no room to go bigger with KDSS. The LX guys are all lifted and actually have more space so thats a bit different. It would be a lot easier if there were more 5 lug options.

In my case I just chose to go the other route and found a very nice, load capable, black, 24 lbs wheel in a 17" 5x150 110.5 hub bore although in a too low offset.
I could have gone heavier for a more appropriate offset but didn't. If you want some suggestions there are some good methods that weigh more and look better than mine. I don't even like my wheel style. Unfortunately theres no "spacer" fix as i need less width not more.

I feel like we are all saying nearly the same thing, so not sure where this conversation is going. With the exception of whether the factory scrub radius is ideal or not. I don't know enough about automobile engineering to go against what Toyota decided. Especially in light of perceived compromises that they may have made not making much sense. Considering it's as easy as changing the wheel offset to adjust scrub radius, i can't imagine they wouldn't put it the most ideal spot for most driving situations.

I guess what this thread is really coming down to is the mistake in putting big P-rated tires on little wheels on a big truck. I'm not sure how many people were shooting for that, but good to get it out there that it's a bad idea.

In Toyota's "defense", they never spec'd a Rock Warrior with P-Rated tires (probably knowing that adding that much soft sidewall to a big vehicle would not be a good idea). The suggested tire to go along with the RW TRD Wheels was always a C-Rated LT tire.

Yeah we can leave what scrub Toyota fits aside. I don't even care, its so easy to figure out on your own what feels best with some spacers.

"Considering it's as easy as changing the wheel offset to adjust scrub radius, i can't imagine they wouldn't put it the most ideal spot for most driving situations."

Thats the problem, its a toyota most driving situation. Not a track or off-road situation.
Like bloc just said, there really Isnt much choice in P at 285/70r17. Not even much in C load.
I dont think its generally a bad idea, what I'm stressing is its not much softer than a C and the only real advantage is weight. Which with AHC ****s up your damping tune.
I don't just think, I pretty much KNOW at this point that it's not ideal choice. You basically have to run them at or above placard and you lose most of the comfort.
Toyota speccing the Rock warriors on Cs shows this as well to some extent. Think about it and read the bulletin, its even specced on the sequoia. I think if they thought they could go up or down a size in P they would have, but again and 8" sidewall with 6,000+ lbs plus on it would take you to an uncomfortable safe PSI to meet their handling expectations. They made a crazy move considering the speed rating R choice is capped at 106MPH. Thats lucky since most are going to be Q at 99 MPH. Something they couldn't even have shipped.

Dont get me wrong there are advantages to P other than weight like silica mix, and noise. What I'm saying is the dis-advantages far outweigh them when you are using them on our platform at plus sizes. LTs have stronger, thicker sidewalls and deeper lugs. And in the case of the Toyo, a different construction method and sidewall pattern too.

Actually I think P285/70R17 on a rock warrior is a great setup on a 200 (or at least a LC where my experience lies), as long as the tire pressure is high enough. And I thought they rode great, better than stock actually. Same weight as stock, marginally taller sidewall than stock for bump absorption, but not so much sidewall that it wouldn't do what I wanted it to on-road. And occasionally I drive mine pretty hard. I wandered around colorado trails a lot with those tires, sometimes aired way down, sometimes not, and they did great. The only puncture I got was a destroyed sidwall from careless driving.. based on what the rock did to my slider I'm betting it would have destroyed an e-load LT as well. Also, got great mileage, because both the sidewall is soft as well as the tread. That thinner tread means it has less internal friction driving down the road, which is ultimately your fuel turning into heat in the tire... less heat than a LT tire, even c-load. That reduced friction and heat build up is the whole reason they require less pressure than a LT format to support the same load.

So I guess I'm not totally clear but I don't really see the same conclusion. Based on so many miles on p-metric AT2s, If I were still on stock shocks I'd be running the Toyo AT3 in P285/70R17 probably around 33psi cold, but my suspension upgrade made it possible to run the heavier, higher pressure tire without the drawbacks I had of a LT tire on stock shocks. And get the deeper tread and larger lugs for better off-road performance.

Dont get me wrong. I chose P myself and dismissed the notion that they puncture easy that is often purported. None of what im saying is to achieve toughness. Although its a welcome upgrade for me. What im saying is true mostly in comparison to a C load at the same size. I think E is a bit much for our truck. But thats going to open a whole can of worms. The gist of what im saying is i think a 285/70r17 in C at 38 PSI on an offset of +45 is the magic formula for the 200 leaving everything else bone stock. And looks like Toyota got half of that right. How much the setup should weigh at the most is determined like weve said on the shocks.

Unfortunately though you didn't A/B the same tire or shocks, only the wheel. Ive now been able to perform that experiment with all variables controlled.
(and wil continue to monitor efficiency). If you had some interim driving between install i would love to hear about it.

Im also certain that running your 285/70 Ps at 33 PSI gave you less MPGs than an equivalent 285/60 or 285/65 at 33 PSI would give you AFTER factoring rotations per mile. The reason for this is the entire point of the thread. Because there is more sidewall deflection and your tire is more out of round. That is going to eat up efficiency no matter if its the same pressure or all things equal. In order to keep the P as round as possible withouth dangerous over inflation, that golden pressure is 36. Thats what I've PAINSTAKINGLY learned over a year of experimentation, and confirmed with the head of Toyo. The door jamb is the MINIMUM safe PSI for a P to P swap. No matter the size. Your spot on that it performed well when the pressure was high enough. But the problem and mine was at that pressure how much comfort did you really gain? Not a lot. So i think it only really achieves one design parameter well and that is shock synergy. Which you found to be the case.
It wouldnt be as comfortable as it should, it wouldnt be as efficient as it should and it wouldnt handle as it should unless you go out of your way to overfill it.

Sidewall buckling is going to happen to a greater degree no matter what your running if you cant achieve the stiffness for your load. You can have it happen on LT just the same as a P. You would just get less on a more rigid tire with the equivalent load matched pressure solely because its stronger for its height. There are less levered forces acting on it the smaller the aspect, so this effect is least noticeable in OE tire sizes.

 

[coleAK]

Thanks for reading and weighing in brother.

I respectfully disagree, not that the rock warriors are a bad choice or wheel, they are great. Its just that there is not enough track width on the OE fitment. Not for performance nor for wheeling off-road. There is just too much body overhang. Thats not a knock on the suspension thats more of a limitation of the size of body on the frame. I honestly think it's purposely overly conservative to retain as much suspension travel as possible and I don't personally take anything OEM as gospel.
They make a LOT of compromises and a few mistakes as well. It is made to suit mass market. We have to remember that too.
The tundra front end conversions here for this and other reasons are very interesting.

Please don't mistake all of my suggestions above for being ignorant of the principles involved or distrustful of Toyota.
Like I've said, my own fitment, +25 is too wide. It's just one of the compromises i had to make due to lack of wheels available.
In the 33" tire size, I think +35 is the sweet spot for all I want to achieve but i will agree its the upper bound, not the ideal all around choice.




Yeah im sorry thats what I meant. Its my suggestion that does not achieve the perfect OE fitment or geometry.
The OE is after all what we would have to describe as "correct".

And thanks, while I am learning a lot about all of this still, i am very observant. I am an engineer myself although not in this field.
I know what the issues are stemming from for the most part and definitely have not got the fit that I want nailed down like I've stated a couple of times.
Also, people are doing outlandish negative offset fitments out there in the truck scene, and we are talking +54 - +25 for my ride.
I was worried but once they were on i found that to the less than 3 inches of total track width increase, which is very negligible, actually improved my handling.

There is a particular stretch of highway under construction between Austin and Houston that was nerve racking to drive on the "perfect" factory setup.
Road imperfections added a scary amount of steering input (not bumps, that was also a diff. issue) and that is due to the low or zero scrub having too much influence on contact patch pivot point. I respect everyones opinion, specially yours, but i will not pretend like Toyota has any standing in performance dynamics specially not on the LC. Also i was very worried my wheel would not self center and it does so beautifully. It also tracks dead straight like its on rails.

I know you dont like to deviate from OEM (says the guy on 35s LOL) but in that vain, isn't the suggested tire offering for TRD BBS forged 18" an OE 265/60?
I think thats crazy conservative. Toyota didn't even plus size the HE tires if i am correct.

I dont think people should shy away from lower offsets unless we have concrete reasons just because its not by the book.
I am very happy with my choice in general other than tire musings, and if you find me a good +35 wheel i will buy it.

Also, since i know you know them, can i have the angles for our setup and whatever calculator you are using for scrub? This one is a bit crude no?

First off retaining as much suspension travel is more important then ground clearance or track width. And an added 3% of track width does nothing for lateral stability.

 

[lx200inAR]

The gist of what im saying is i think a 285/70r17 in C at 38 PSI on an offset of +45 is the magic formula for the 200 leaving everything else bone stock.

So all of this conversation is to say Toyota was right all along?

This is literally 5mm of offset and exactly the tire Toyota spec'd for the "performance upgrade" option from TRD for a Land Cruiser.

 

[TeCKis300]

There's so many details being talked about here and I'm afraid we're conflating concepts and points to lead to anecdotal conclusions.

- Even though I run LT and Floatation sizes, I don't agree with the conclusion that Ps aren't a good fitment for the casual modder. P-metric are stock fitments after all. If trying to maximize all the great stock qualities with stock suspension including ride, efficiency, handling, I wouldn't hesitate to recommend P tires. Provided it is used with the right offset, wheel, and tire sizes. LT tires will have other compromises (which many of us accept).
- The minor weight changes are not as big an impact on MPG as it's made out to be. It's probably a secondary or tertiary factor (unless getting into really large and heavy sizes). With tire type (AT), sizing diameter (gearing), being larger impacts
- Offset has more impacts than being understood and I don't agree that stock has it wrong. It's not just aesthetics or track width. Nor is it about being aggressive or not for the following - one of the major untoward impacts of scrub radius is because it effects steering geometry. Basically get the offset too wrong, and the front tires don't steer together towards that same imaginary point in a turn any longer. They will fight and scrub, perhaps even causing a tire to break traction in the low grip environments. The fighting also is an extra force the sidewalls have to deal with, and on taller aspect tires, can give the perception of sidewall softness in turns. It's why this should be one of the larger considerations

 

[Itsky]

I agree. I appreciate everyone sharing their experiences, but it seems to be that someone is jumping to conclusions.

 

[TeCKis300]

Were you not lifted though when you ran +35? And how are you sure it was properly aligned?
The symptoms you described can be easily attributable to both those things and accentuated when towing is involved.
As I attempted to describe earlier, any lift you do throws factory alignment specs out the window.
This is why I have yet to do either of those things. Interestingly enough my tires are wearing perfectly even as well after having been aligned prior to my setup changing.

Let me end on another approach. Following the logic at play here, if a single additional 1" of pos scrub is as impactful as you say it is, then how can that principle not also apply to going 20-30mm wider in tire on OE offsets? Especially when considering camber impact at high steering angles where that measure would effectively double.

- I was lifted through part of when I ran +35 offset on 33.2" tires. Yes, I did an alignment pre-lift and it was always spot on having good and even tire wear through 30k miles. Still sold the Falkens for $300 a set after that! Great aggressive tire that I miss over AT3s.
- No, pulling or pushing of steering is a well understood impact of aggressive offsets. Load makes it more noticeable
- Width can have it's own impacts but not offset as that is relative to the centerline of the tire, independent of width

 

[AnyMal]

So all of this conversation is to say Toyota was right all along?

This is literally 5mm of offset and exactly the tire Toyota spec'd for the "performance upgrade" option from TRD for a Land Cruiser.

No they spec a +50. Im not going to type any more.

 

[lx200inAR]

No they spec a +50. Im not going to type any more.

50 - 45 = 5mm

But i agree, i don't think there is much more to gain here.

 

[AnyMal]

There's so many details being talked about here and I'm afraid we're conflating concepts and points to lead to anecdotal conclusions.

- Even though I run LT and Floatation sizes, I don't agree with the conclusion that Ps aren't a good fitment for the casual modder. P-metric are stock fitments after all. If trying to maximize all the great stock qualities with stock suspension including ride, efficiency, handling, I wouldn't hesitate to recommend P tires. Provided it is used with the right offset, wheel, and tire sizes. LT tires will have other compromises (which many of us accept).
- The minor weight changes are not as big an impact on MPG as it's made out to be. It's probably a secondary or tertiary factor (unless getting into really large and heavy sizes). With tire type (AT), sizing diameter (gearing), being larger impacts
- Offset has more impacts than being understood and I don't agree that stock has it wrong. It's not just aesthetics or track width. Nor is it about being aggressive or not for the following - one of the major untoward impacts of scrub radius is because it effects steering geometry. Basically get the offset too wrong, and the front tires don't steer together towards that same imaginary point in a turn any longer. They will fight and scrub, perhaps even causing a tire to break traction in the low grip environments. The fighting also is an extra force the sidewalls have to deal with, and on taller aspect tires, can give the perception of sidewall softness in turns. It's why this should be one of the larger considerations

View attachment 2821773

Sorry, no offense, but you're just not reading or understanding and I'm sure some of that is my fault as this has been a lot to write.
I wont be putting in any more effort. Im officially in low effort mode now. I dont need to convince anyone of anything.
Im trying to convey nuances that aren't being interpreted properly.

Im not suggesting scrub is an irrelevant parameter. We should move on from that. I don't know why you're insistent there.
Just because i feigned ignorance on it earlier doesn't mean I'm asking for a lesson. In your words, I was being nice.

Now, IMO though, Toyota is too conservative with amount of Positive scrub, which is an inherent design FEATURE of double wishbone.
The amount I'm suggesting is more than you are comfortable with and we certainly are not going to agree about what Toyota is doing wrong or right.
Specially not with you because i know you don't like to deviate. Thats wise and I respect that. But you're taking it too far.

Now where there is fact involved, Ps aren't good at plus sizes. Period. Not saying they wont work, but they are suboptimal for 3 pages of reasons i described.
We can see that Toyota themselves, which is gospel to the forum and yourself went with an LT for a 33". Even considering limited choices what you are stating doesn't make sense. Toyota put a suboptimal package out? MY GOD! That contradicts the entire ethos of the "arguments" ive been presented with thus far.


Another thing is you should know of all people you were lifted so your geometry was not where it should have been. Im not. I understand that it has a huge impact on suspension geometry. Much more than you claim offset DIFFERENCES of 10mm would produce. Which is why im getting out of this conversation.
Thats 10 flavors of inaccurate. You didn't even acknowledge that i mentioned width increases on the same offset has a similar impact at wide steering inputs.

Can you see why im kind of done talking?
I wish offsets hadnt even come up. Now, anyone is going to claim appeal to authority to somehow invalidate the facts im presenting since i have a preference there that is not popular.

PEACE OUT YALL. Just enjoy your truck. If i was OP i would lock this thread.

 

[TeCKis300]

Sorry, no offense, but you're just not reading or understanding and I'm sure some of that is my fault as this has been a lot to write.
I wont be putting in any more effort. Im officially in low effort mode now. I dont need to convince anyone of anything.
Im trying to convey nuances that aren't being interpreted properly.

Im not suggesting scrub is an irrelevant parameter. We should move on from that. I don't know why you're insistent there.
Just because i feigned ignorance on it earlier doesn't mean I'm asking for a lesson. In your words, I was being nice.

Now, IMO though, Toyota is too conservative with amount of Positive scrub, which is an inherent design FEATURE of double wishbone.
The amount I'm suggesting is more than you are comfortable with and we certainly are not going to agree about what Toyota is doing wrong or right.
Specially not with you because i know you don't like to deviate. Thats wise and I respect that. But you're taking it too far.

Now where there is fact involved, Ps aren't good at plus sizes. Period. Not saying they wont work, but they are suboptimal for 3 pages of reasons i described.
We can see that Toyota themselves, which is gospel to the forum and yourself went with an LT for a 33". Even considering limited choices what you are stating doesn't make sense. Toyota put a suboptimal package out? MY GOD! That contradicts the entire ethos of the "arguments" ive been presented with thus far.


Another thing is you should know of all people you were lifted so your geometry was not where it should have been. Im not. I understand that it has a huge impact on suspension geometry. Much more than you claim offset DIFFERENCES of 10mm would produce. Which is why im getting out of this conversation.
Thats 10 flavors of inaccurate. You didn't even acknowledge that i mentioned width increases on the same offset has a similar impact at wide steering inputs.

Can you see why im kind of done talking?
I wish offsets hadnt even come up. Now, anyone is going to claim appeal to authority to somehow invalidate the facts im presenting since i have a preference there that is not popular.

PEACE OUT YALL. Just enjoy your truck. If i was OP i would lock this thread.

I hope you don't take offense as I was more interested in talking about generalized tech and detailed considerations. Less about your specific fitment. Even though we may look at things slightly differently, the reality of choices for your specific trades, would likely have led to the same LT and wheel offset fitments you choose. I'm not just saying that as I pretty much ran LT 33s with +35 offset for more than a few years. It'll be a great setup and I hope it meets your expectations.

 

[AnyMal]

I hope you don't take offense as I was more interested in talking about generalized tech and detailed considerations. Less about your specific fitment. Even though we may look at things slightly differently, the reality of choices for your specific trades, would likely have led to the same LT and wheel offset fitments you choose. I'm not just saying that as I pretty much ran LT 33s with +35 offset for more than a few years. It'll be a great setup and I hope it meets your expectations.

I mean don't get me wrong, Im still looking at these though More optimal.