What about food, adult beverages, wine, beer, a nice drink after dinner with a cigar?
No need to suffer with a little advance planning.
Chairs, table, cotts?
Recovery gear?
Increase Payload Capacity
- Thread starter Marinna
- Start date
No need to suffer with a little advance planning.
Chairs, table, cotts?
Recovery gear?
Payload is determined by a number of factors:
Only Toyota knows what are the specific limits of each one of these elements (except tires which you can read from the sidewall).
Installing air bags will reduce sag, but not increase payload capacity.
Going over GVWR will certainly reduce the lifespan of some of these elements. By how much - only a detailed engineering analysis and testing will tell, and only Toyota has the detailed information / models to assess it. Anything anybody else says is pure speculation. For sure, things like wheel bearing or ball joints won't last as long as originally designed.
Going over GVWR is also unsafe. You simply can't know which of the parts listed above is the "weak link" that will fail first. A ball joint or wheel bearing failing while on a curve on a mountain road is not fun.
- Tire load rating
- Wheel hub / bearings
- Axle(s)
- Suspension components (springs, control arms, ball joints, bushings, ...)
- Frame (including suspension attachment points)
Only Toyota knows what are the specific limits of each one of these elements (except tires which you can read from the sidewall).
Installing air bags will reduce sag, but not increase payload capacity.
Going over GVWR will certainly reduce the lifespan of some of these elements. By how much - only a detailed engineering analysis and testing will tell, and only Toyota has the detailed information / models to assess it. Anything anybody else says is pure speculation. For sure, things like wheel bearing or ball joints won't last as long as originally designed.
Going over GVWR is also unsafe. You simply can't know which of the parts listed above is the "weak link" that will fail first. A ball joint or wheel bearing failing while on a curve on a mountain road is not fun.
- Thread starter
- #23
I started this thread on the basis of the fact that GX550 can support 1400-1500 lbs payload. So it is not based on the assumption of “Only Toyota knows”…
The hybrid battery is probably about 200 lbs. So we should be able to recover the remaining 300 lbs without significant modification.
and yes more payload = more wear. But I am not buying a car so it can sit in the garage just to stay pretty.
I bet there is a dead easy way to calculate this for the high level ballpark. But I haven’t been able to find a trustworthy source yet
The fact that the LC and the GX are based on the same frame does not mean that specific components are identical.
For example, rear axle housing of the LC is part # 42110-60F90. Rear axle housing of the GX is part # 41110-60C70
This means that they are two different parts. 99% sure that they also have different load capacity.
Wheel bearing on the other hand are identical part # 42450A (RH) and 42450B (LH) - just to show you that Toyota and Lexus use same part numbers across both brands
I'm sure that if you look into the details of both vehicles, you will find that some suspension parts are identical, while other are different. The devil is in the detail. Only Toyota knows these details.
I don’t think you’re going to find a “dead easy” way to calculate the changes required to increase your payload. Calculating GVWR requires intimate knowledge of the load ratings of dozens of OEM parts, which is why some people mentioned “only Toyota knows.” It’s far more complicated than just suspension.
A much simpler path would be to recover payload by removing weight by calculating the weight of the material you want to add (people, parts, and cargo), doing the math on how far over GVWR that takes you, and then crafting a plan to lighten the weight of the vehicle by the amount over GVWR you are.
In other words, you’re probably going to need someone with inside knowledge of Toyota engineering in order to increase payload. Much easier would be to decrease payload utilization - but you run the risk of degrading the quality of the vehicle in order to be able to haul around more stuff. Bringing less stuff is usually the best answer.
A much simpler path would be to recover payload by removing weight by calculating the weight of the material you want to add (people, parts, and cargo), doing the math on how far over GVWR that takes you, and then crafting a plan to lighten the weight of the vehicle by the amount over GVWR you are.
In other words, you’re probably going to need someone with inside knowledge of Toyota engineering in order to increase payload. Much easier would be to decrease payload utilization - but you run the risk of degrading the quality of the vehicle in order to be able to haul around more stuff. Bringing less stuff is usually the best answer.
- Thread starter
- #26
This may be a good topic to challenge ChatGPT. Usually as rule of thumb for most systems, you only have to worry about the small amount of variants that cause biggest spec gaps. I am only going after these parts. You shouldn’t need to go through every single details to figure this out. Whether the key components are aftermarketable would be another question though.
I second whoever says you only need to swap out the springs for HD springs with 0 lift.
But officially doing it not sure, I think that's why in Australia they are under more strict guidelines, could reach out to some Australian folks.
But officially doing it not sure, I think that's why in Australia they are under more strict guidelines, could reach out to some Australian folks.
ChatGPT does not have access to Toyota's detailed technical documentation (nor is it shared externally though any of publicly accessible means like TIS). For example, only Toyota (or their supplier) have the FEA model of the rear axle housing assembly which would tell you exactly how much load it can handle. The same applies to all the other components (control arms, etc.).
In the end you can load your LC as much as you want. Just bear with the consequences, especially if your actions impact other road users. If anything happens it will be your responsibility, not Toyota's.
- Thread starter
- #29
You don’t necessary need every single piece of details. I think you are over-complicating this. Physics applied on most of these body-on-frame very similarly. The suspension and breaking mechanism on LC is nothing remotely new. Even GX550’s EKDSS works similarly than the 4Runner’s KDSS.
You don’t need to remind people with these what-if. Just changing the stock wheels could have more than a dozen of these “what-if”. Liability is common sense and everybody who spent money on their cars knows that. Keep saying it doesn’t make it more or less important.
Sounds like you have it figured out OP. Good luck!
- Jul 7, 2025
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This is the second time ChatGPT has been presented as a reliable resource. If I were able to disclose what I specifically do for a living, and where I do it/who I do it for, you would believe me when I say: ChatGPT is fun anecdotally, but CANNOT be trusted any more than reading 1000 opinions on the same subject and coming to a conclusion. The difference being that ChatGPT is making that decision for you based only on historical patterns.
The only “simple” answer to your questions is either
1) reduce weight to accommodate weight gain
2) modify suspension, keeping in mind that you are only LIKELY upgrading the limiting component. I personally think, for just 2-300 pounds, better rear springs will safely address the problem for temporary use cases. You aren’t increasing GVWR, but you’re supplementing it in a sensible manner.
I, for one, can’t continue to read sound answers be addressed with repeats of the amount of weight you need increased, oversimplification or dismissals of the complexity of feedback, or referrals to Chat friggin GPT. At this point we’re just chasing reactions and interactions. Have fun
The only “simple” answer to your questions is either
1) reduce weight to accommodate weight gain
2) modify suspension, keeping in mind that you are only LIKELY upgrading the limiting component. I personally think, for just 2-300 pounds, better rear springs will safely address the problem for temporary use cases. You aren’t increasing GVWR, but you’re supplementing it in a sensible manner.
I, for one, can’t continue to read sound answers be addressed with repeats of the amount of weight you need increased, oversimplification or dismissals of the complexity of feedback, or referrals to Chat friggin GPT. At this point we’re just chasing reactions and interactions. Have fun
- Thread starter
- #32
I actually did a quick research on this through ChatGPT. I think this is fairly doable. Like what I thought, all we have to do is to find out the weakest point of GVWR across the major 4-5 subsystems and enhance it. Obviously certain subsystem will be very costly than other to upgrade, but that is a separate subject.
This is not really about whether ChatGPT is trustworthy or not. You never copy and paste. It’s about your own judgement, the data you have, assumptions, and generally understanding of high school physics.
I’ll spend some time tonight to do some quick approximation and publish here. It won’t be perfect. Maybe we can all make our assumption to create one you would be happy about yourself and comes out some good recommendations for parts to fortify our car.
Last edited:
- Jul 7, 2025
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- 245
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- '25 LC 1958 || '25 Sequoia LTD TRD || '05 TJR || '24 Polaris Ranger 1000 Crew
Ask for advice, tell people their advice is too complicated, settle on the issue being a simple fix w/ simple math that is supported by ChatGPT.
You got this apparently, I’ll see my way out. When you’re done with that though, you got way more sound advice from members ^^ than most threads get on here. Good luck.
NATO jerrycan? 20 pounds each. How much fuel do they hold? 5 gallons each?
41 lbs. per minimum when full: Can at 11lbs. Fuel at just over 6lbs./gallon.
All the weights are too conservative IMO only 2.5 gallons of water per day to drink, cook, wash up? Sleeping gear not listed, personal luggage of 25lbs for 3 days?
Hope you’re not going remote and outside of cell phone range, nothing listed for emergencies, extra clothing (soaked or other), water, emergency supplies. This is why too many people require rescue from the back country these days. Where are the other adults sleeping? In the car, there will be stuff in there that won’t make that too fun!? What about food weight and space?
IMO if you’re venturing out on a multi day trip with 4 people in this vehicle you need a trailer of some sort for either sleeping or cargo or combo of both. Even better would be another vehicle, in case one is stuck or breaks down.
Plan for the worst when going off grid. What happens when you get caught in weather, clothes soaked to the bone, stuck or disabled?
I don’t even see what you have listed for cargo as fitting as is, can’t use the roof rack if you have a RTT.
Our day trips with small ice chest, recovery box (normal ice chest size), 4 recovery boards, camera, and a few guns fills the cargo area to level with the seats add in the passengers and I’m at payload.
May need to rethink your adventure? At least make sure the others are good with your plans with what sounds like no backup?
To the original point tires and springs is about all you can do economically. You could put in airbags but those could fail or require an air compressor out on the trail. The stiffer springs won’t be fun when unloaded though.
Is the LC250 a good overlanding platform with four adults? I don’t think so and IMO there isn’t any economical solution available in the market for that if also using as a daily driver or all around use vehicle. It may be decent with 2 adults but still not great due to range and payload limitations. I think it can be made to be great with 2 adults but IMO it would need to be dedicated for overlanding in that case and would suck for everything else afterwards.
- Thread starter
- #36
So I did more research on how to determine GVWR on LC. This is how much I (I meant ChatGPT) have found:
For GVWR, we consider 5 subsystems:
My 2024 LC FE has GVWR 6835 lbs, curb weight 5038 lbs.
1. Axel & Tire
This is easy. On the door stickers the GAWR for front and rear axle are 3540/4100 lbs each. Also we have to consider the tire's load index/weight though this is usually stronger than axel. So GVWR for this system is:
GVWR_axle_tire = min(GAWR_front, Max load weight front) + min(GAWR_rear, Max load weight rear) = 7640 lbs
2. Suspension
I am still looking how to properly estimate the jounce distance with a given weight. Some links I saw seems to suggest that LC has a deficit comparing to GX550
3. Brake
This is thermal. There are equation to estimate max GVWR your car can support. I am not too good at it neither. You have to make a series of assumption in order to calculate it correctly. But one thing clear to me is that LC's brake system, including rotor and pad, has significantly lower thermal capacity comparing to GX550. So definitely this needs to be a focus in order to improve GVWR.
4. Structure
I am just gonna assume LC has an identical structure to GX550. So here I'll just assume GVWR for structure is 7165 lbs, which is the GVWR for GX550 Trail+
5. Handling and Load Distribution
I don't know how Toyota or DoT estimate this. But one rule of thumb I read is that for SUV keep at least 55% weight on front axle in order to retain "steering authority".
The vehicle GVWR is calculated as:
GVWR_vehicle = min(GVWR_axel&tire, GVWR_suspension, GVWR_brake, GVWR_structure, GVWR_handling)
Basically, fix your weakest point first.
As I am still trying to learn this (never mechanically designed a car, I only design ADAS), I think for my use of overlanding investing in potential modification on brake thermal capacity and suspension would address the achilles heel of LC's weak payload capacity.
Any comment would be welcome.
For GVWR, we consider 5 subsystems:
- Axle and Tire
- Suspension (jounce distance)
- Brake (thermal capacity)
- Structure (Frame)
- Handling and load distribution
My 2024 LC FE has GVWR 6835 lbs, curb weight 5038 lbs.
1. Axel & Tire
This is easy. On the door stickers the GAWR for front and rear axle are 3540/4100 lbs each. Also we have to consider the tire's load index/weight though this is usually stronger than axel. So GVWR for this system is:
GVWR_axle_tire = min(GAWR_front, Max load weight front) + min(GAWR_rear, Max load weight rear) = 7640 lbs
2. Suspension
I am still looking how to properly estimate the jounce distance with a given weight. Some links I saw seems to suggest that LC has a deficit comparing to GX550
3. Brake
This is thermal. There are equation to estimate max GVWR your car can support. I am not too good at it neither. You have to make a series of assumption in order to calculate it correctly. But one thing clear to me is that LC's brake system, including rotor and pad, has significantly lower thermal capacity comparing to GX550. So definitely this needs to be a focus in order to improve GVWR.
4. Structure
I am just gonna assume LC has an identical structure to GX550. So here I'll just assume GVWR for structure is 7165 lbs, which is the GVWR for GX550 Trail+
5. Handling and Load Distribution
I don't know how Toyota or DoT estimate this. But one rule of thumb I read is that for SUV keep at least 55% weight on front axle in order to retain "steering authority".
The vehicle GVWR is calculated as:
GVWR_vehicle = min(GVWR_axel&tire, GVWR_suspension, GVWR_brake, GVWR_structure, GVWR_handling)
Basically, fix your weakest point first.
As I am still trying to learn this (never mechanically designed a car, I only design ADAS), I think for my use of overlanding investing in potential modification on brake thermal capacity and suspension would address the achilles heel of LC's weak payload capacity.
Any comment would be welcome.
- Thread starter
- #37
I just randomly made up some numbers to show how fast the payload could stack up.
For my planned use I will have likely only 2 people, no RTT, definitely 10-15 gallon spare fuel, and still thinking about a pair of after market bumpers, which will add 100-150 lbs at least. Water only for drinking and cooking so not gonna be that bad for 2 people
I would think if its only 200-300lbs, the increased capacity of the tires alone are all you needed. Unless folks like you are experiencing a suspension that bottoms out or rides on bump stops etc.
The stock SL rated tires give the vehicle the best combination of ride, efficiency and noise. 90% of these vehicles will live their lives predominantly on road. The Standard tires are fully capable of driving on dirt roads, logging roads etc. Last thing I want to listen to for 5.5 hrs are singing tires. Gets old really fast IMHO. Also, many AT tires are NOT as good in rain as their tread patterns are not designed top clear water, they are designed to engage rough surfaces.
A similar argument on the opposite side of the aisle is why don't serious sports cars come with slicks or DotR's? Some do come with DotRs now but their usability on public roads is severely limited by #1 temps and #2 RAIN! Those DotR shod cars are to pump up test numbers. I have had the unpleasant experience of cold PZeros........the results were, not a mark on the road.
The stock SL rated tires give the vehicle the best combination of ride, efficiency and noise. 90% of these vehicles will live their lives predominantly on road. The Standard tires are fully capable of driving on dirt roads, logging roads etc. Last thing I want to listen to for 5.5 hrs are singing tires. Gets old really fast IMHO. Also, many AT tires are NOT as good in rain as their tread patterns are not designed top clear water, they are designed to engage rough surfaces.
A similar argument on the opposite side of the aisle is why don't serious sports cars come with slicks or DotR's? Some do come with DotRs now but their usability on public roads is severely limited by #1 temps and #2 RAIN! Those DotR shod cars are to pump up test numbers. I have had the unpleasant experience of cold PZeros........the results were, not a mark on the road.
- Thread starter
- #39
That’s what I thought until I start to run some numbers. It turns out that even stock tire which load index is 116 has better weight capacity than your axles. So before your tires are crushed by the load your axles will break first. But the axles weight rating is still far better than the GVWR so it is not the problem we need to focus.I would think if its only 200-300lbs, the increased capacity of the tires alone are all you needed. Unless folks like you are experiencing a suspension that bottoms out or rides on bump stops etc.
The stock SL rated tires give the vehicle the best combination of ride, efficiency and noise. 90% of these vehicles will live their lives predominantly on road. The Standard tires are fully capable of driving on dirt roads, logging roads etc. Last thing I want to listen to for 5.5 hrs are singing tires. Gets old really fast IMHO. Also, many AT tires are NOT as good in rain as their tread patterns are not designed top clear water, they are designed to engage rough surfaces.
A similar argument on the opposite side of the aisle is why don't serious sports cars come with slicks or DotR's? Some do come with DotRs now but their usability on public roads is severely limited by #1 temps and #2 RAIN! Those DotR shod cars are to pump up test numbers. I have had the unpleasant experience of cold PZeros........the results were, not a mark on the road.
I think chance are good that 200-300 additional load beyond GVWR is going to be just fine with the margin manufacturer put on GVWR (this is less than 5%) But my original assumption is to make it safer when carry weights so that is not my point.
Supposedly the GX550 has bigger brakes than the 250. Maybe those can be swapped in.
I'd love to see someone try it and find out if it's possible without too much work.
I'd love to see someone try it and find out if it's possible without too much work.
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