Payload Talk: how can you improve it?

[devinsixtyseven]

lol...Pulling the carpet does seem a bit silly, when it's 20# and I've added hundreds of pounds of trail armor.

It might sound like O/C gram counting, but, think of Brady's lightweight M8000 build. It wasn't one single piece, it was a few small items applied together bringing the weight down. So far I've swapped ~250# of dead weight and comfort items for ~350#+ of trail armor, all of which rides inches above the axles vs feet.

Also consider, when you add protection or heavier drivetrain components (even if it's just larger tires), you're biasing the center of gravity lower to the ground. High center of gravity isn't just something rock crawlers need to consider, it also has a huge effect on vehicle dynamics during hard braking, and of course slalom maneuvers.

-Sean

 

[mike h]

consider, when you add protection or heavier drivetrain components (even if it's just larger tires), you're biasing the center of gravity lower to the ground.n

Physics question - how does the increased weight that effectively lowers the CG affect rooftop cargo? (Sidestepping completely the fundamental argument that we should avoid rooftop storage)

Example: a stock Xterra - relatively tall and light truck. Or a Disco/Defender, 60/80/100 LC - the physics should hold true in proportion to the trucks hieght/weight/suspension.

Mods 1: Sliderz and skids, heavier tires/wheel, with backspacing that moves the wheels a couple inches wider in stance, which adds a degree or so in terms of potential rollover angle. Adds 300+ lbs positioned below the frame. At this stage, is the vehicle better prepared to deal with a 200lb roof load compared to stock?

Mods 2: add front and rear bumpers, rear spare, jerrys, winch - now you've added 500 lbs at or above the frame, cantilevered at the far ends of the vehicle. How does this affect a rooftop load limits?

I don't have a clue. But I look at the fishing boat and cargo ship industry - as they fill the holds below waterline they gain leverage via lower CG to continue to stack cargo above waterline. I'm using the vehicles frame as a relative waterline - maybe axles is more appropriate.

I understand it may be very much apples and oranges, math and physics aren't my strong points - feel free to tell me the concept is bunk.

m.

 

[devinsixtyseven]

Physics question - how does the increased weight that effectively lowers the CG affect rooftop cargo? (Sidestepping completely the fundamental argument that we should avoid rooftop storage)

Mods 1: Sliderz and skids, heavier tires/wheel, with backspacing that moves the wheels a couple inches wider in stance, which adds a degree or so in terms of potential rollover angle. Adds 300+ lbs positioned below the frame. At this stage, is the vehicle better prepared to deal with a 200lb roof load compared to stock?

Mods 2: add front and rear bumpers, rear spare, jerrys, winch - now you've added 500 lbs at or above the frame, cantilevered at the far ends of the vehicle. How does this affect a rooftop load limits?

Mods 1: Short answer is yes. Mods 2: It won't change your rooftop load limits, that depends on the strength of your cab, but the effect on vertical COG is the same as if you'd added 500# anywhere else at the same vertical location.

It works like youre saying...the center of gravity is the point location of the sum of all the masses in consideration.

What doesn't get consideration is swing weight--50# in a single point has the same CG as 25# separated equal distances apart, but the two will react differently to any change in angular momentum. It's probably not that big a deal top to bottom, but end to end I suspect you will see a difference, particularly going from a vehicle with a large bumper and winch hanging out in front of the front wheels and a tire/gear carrier rear bumper, to a vehicle with the same weight and wheelbase but with equal mass centered between the axles. They will react different to dynamic loading, even though they look the same at first glance on paper.

Building any vehicle is all just managing tradeoffs...nobody's gonna put their winch in the middle of the truck, sometimes we have to use roof racks, and the versatility of a rear swingout tire carrier can't be denied.

All that means to us is that the amount out of our gourds (from not at all to completely) that we may drive is directly related to the mass distribution (from ground level to too high, and from centered to past the bumpers) of our vehicles.

-S

 

[mountainpete]

Mark,

First, I admit that I haven't read through every single post so far, but I thought I would put out a different perspective on payload - one that may draw some flames my way... Here goes anyways :littlefriend:

Simply: Don't trust the North American numbers.

Why? The answer is politics and money. So many of the figures in North America are skewed due to potential lawsuits from an over-zealous public or are "honed" in order for manufacturers to meet government imposed targets. One case in point is the PT Cruiser - ever look to see what it is officially classified with the government? It's listed as a van. It's long been known that by classifying vehicles like this as Vans, it has allowed Dodge and others to keep the average fuel economy of their "truck line" high enough to meet federal standards.

Another huge example is Volkswagen and Kia when it comes to towing capacity. Check the towing capacity on a North American Passat. If I remember correctly, it is about 1500 lbs. Go to the UK with the EXACT same vehicle it is rated for twice that amount. And did you know that a Kia was rated as the Caravan hauler of the year in the UK? A Kia sedan as a tow vehicle?

I'm not saying there aren't other factors involved. Drivers in other continents seem to have a greater acceptance of slowing down when the weight gets heavy while us North Americans just seem to want a bigger diesel.

So take a look at other the sister vehicle to the Frontier overseas - the Navara. We all know there are different engine options, but as far as I know the frame and suspension is the same - yet the payload is listed as 1050 kg - or about 2300 lbs.

Bottom line is - get all the facts on the *true* capacities and then make your decisions.

Just some ramblings :elkgrin:

 

[mike h]

mountainpete - very interesting - I hadn't compared US vs global specs. My initial googling suggests the Nissan Terrano (non-US Pathfinders) is listed with about a 500# increase in payload capacity. May be a little bit of an unfair comparison, but I'll look into it.

Regardless, my Pathfinder, with an Old Man Emu suspension, has carried exceeded the factory payload weight and done so with a degree of safety and performance that the factory suspension could not handle. I suspect that holds true for any vehicle that upgrades suspension.

m.

 

[mountainpete]

mountainpete - very interesting - I hadn't compared US vs global specs. My initial googling suggests the Nissan Terrano (non-US Pathfinders) is listed with about a 500# increase in payload capacity. May be a little bit of an unfair comparison, but I'll look into it.

Regardless, my Pathfinder, with an Old Man Emu suspension, has carried exceeded the factory payload weight and done so with a degree of safety and performance that the factory suspension could not handle. I suspect that holds true for any vehicle that upgrades suspension.

m.

Mike - I used to have a 97 Pathfinder myself. That was a highly under-rated expedition vehicle. It was reliable, amazingly capable in stock form (albiet with the right tires) and had a decent amount of room. You probably already seen it, but if it's still around check out Dean Thayers truck. I remember chatting with him years ago - he was doing some amazing things with his Pathy! I think he used a screen name of something like xplorex4.

Pete

 

[articulate]

Mark - I have run into similar questions with my 97 Pathfinder. It's impossible to find real specs for the GVW outside of the door jamb sticker. And no suspension manufacturer is going to claim an increase based on thier suspension products for liability concerns.
. . .
Overall I think all you really have to do is gas it up and go. It's almost too easy!

m.

Great story about your Pathfinder, and I'm glad you find that she's hanging tough after all these years and trips. Your account is a perfect testament to the durability of that Pathfinder. You've loaded her up, cared for her, and traveled well. 115K miles later, you're still dancing on the same wheel bearings and CV axles.

This discussion's getting more and more interesting.

It might sound like O/C gram counting, but, think of Brady's lightweight M8000 build. It wasn't one single piece, it was a few small items applied together bringing the weight down. So far I've swapped ~250# of dead weight and comfort items for ~350#+ of trail armor, all of which rides inches above the axles vs feet.

-Sean

Totally. I think it's cool to be mindful of things like that sub-50 Taco nose project. You can the effect of adding on armor weight by tossing out 20 lbs here and 20 lbs there. The whole thing has me feeling awfully consumerist to tack on 120 lbs to the front end and wonder, "Gee, I sure am losing payload capacity. How can I increase it now?" I could start by taking off that mammoth bumper . . .

The sub-50 project was eye-opening. Man! If you can take that concept and apply it in some other places around the vehicle . . . does a diff guard have to be 1/4" thick, for instance? No, you could have a lighter one. Especially if the rig isn't meant for difficult trails.

Similarly, I've got the fender space for a 33" tire and also the capability to carry one as a spare. But I'm not going to do that. 32" is fine. I've prioritized the economy and weight savings over the taller tire. My ego might change in the future, though. There's always that.

Mark,

Here goes anyways :littlefriend:

Simply: Don't trust the North American numbers.

The Aussie version will accept another 400 lbs (on the money). But there are some difference between these vehicles from continent to continent. For instance, the UK has one with a limited slip differential. Not available in the US - potentially different drive train components, no? Like others, just a rambling thought.




Cool input, guys. This has been enlightening. We do keep the "Premium" maintenance schedule, like Brian suggested. An ounce of prevention . . .

 

[mike h]

Mike - I used to have a 97 Pathfinder myself. That was a highly under-rated expedition vehicle. It was reliable, amazingly capable in stock form (albiet with the right tires) and had a decent amount of room. You probably already seen it, but if it's still around check out Dean Thayers truck. I remember chatting with him years ago - he was doing some amazing things with his Pathy! I think he used a screen name of something like xplorex4.

Pete

Dean is still around, he is the moderator of the R50 forum at 4x4parts.com, and continues to pioneer the R50 build. I'd say his is the best built in the US, and he is a smart and confident driver. I followed his lead in many ways.

My Pathfinder build-up is well documented on my website: click on the Into Nissan Pathfinders? link.

 

[Benjisan]

I'm surprised no one has mentioned one of the best ways to lighten your payload...lay off the Krispy Kremes. Seriously, most of us could stand to lose twenty pounds or so. Now if your wife needs to lose twenty pounds or more to lighten the payload, I'm not sure how I would approach that subject. In fact, I've learned to completely avoid any topic even remotely dealing with women and weight, even if she doesn't need to lose any. I can just imagine that conversation:

Me: "Dear, I need you to lose thirty pounds."
Her: "WHAT?!"
Me: "Ah baby, it's not you, it's my trucks GVW."
Her: "Yeah, I'm gonna need you to sleep on the couch for the next month. It's not you, I'm worried about our GBW. Gross Bed Weight."

 

[devinsixtyseven]

I'm surprised no one has mentioned one of the best ways to lighten your payload...lay off the Krispy Kremes. Seriously, most of us could stand to lose twenty pounds or so. Now if your wife needs to lose twenty pounds or more to lighten the payload, I'm not sure how I would approach that subject. In fact, I've learned to completely avoid any topic even remotely dealing with women and weight, even if she doesn't need to lose any. I can just imagine that conversation:

Me: "Dear, I need you to lose thirty pounds."
Her: "WHAT?!"
Me: "Ah baby, it's not you, it's my trucks GVW."
Her: "Yeah, I'm gonna need you to sleep on the couch for the next month. It's not you, I'm worried about our GBW. Gross Bed Weight."

:xxrotflma

Funnay aside, that's my justification for strapping 20# of water to the backs of my seats. I could stand to lose about 15#.

Engineers love to improve efficiency...it's how we're trained. Unfortunately you almost always have to feed money (or time to DIY) in to the system to include many of the efficiency gains available, and there's always a three way trade between what you want, what you need, and what works best. What we need is often far below what we want, and very rarely do our needs approach the climatic or technical extremes requiring what works best.

For all the gutting, trimming, lining, tires etc. I've done, my truck still has a bone stock drivetrain (ok, not for long anymore)...there was no need for anything different.

 

[mike h]

A lot of the weight savings make perfect sense - in the age of superior synthetic winch cables, there is no reason to run a steel wire, other than financial. The backpacker or motorcyclist approach to gear is a foreign concept to vehicle-dependent-explorers, who get stuck in the "if it fits, I'll bring it" mentality.

How many times do you see someone with 10 gallons of fuel, and 20 gallons of water, yet after 4 days they haven't needed any fuel and drive out with half the water reserves? They carry a ton of water, but do not have a simple water purification pump/filter, which is all you really need assuming you will be near water on occasion. Carry a 5 gallon water jug and refill it every chance you get.

All that extra camping gear, like a roll-up table, which is a handy thing to have - but what if you only use it for 2 hours and drive it around for 40 hours? I see people set up their roll-up table next to a provided picnic table...huh? A use-to-weight-ratio approach can help a lot to lighten the load.

I pay less attention to what I bolt onto my vehicle than what I put in it, although the bolt-on's need the same weight-to-use ratio philosophy. If you're not routinely in big rocks, why have 300# of massive belly skids, when a much lighter duty set would be sufficient.

And I totally agree with the tire size - 32s vs 33s: especially if the vehicle was designed to turn 31s, you stress a lot of other parts as you bump up tire sizes. At the end of the day - was there really an obstacle that would have prevented you from reaching your destination solely because you have 32s and not 33s?

m.

 

[RAM5500 CAMPERTHING]

and the transmission will run hotter/shift slower under power/wear clutches sooner.

In my opinion, this would be your biggest problem/concern.

Maybe add a tranny cooler if it doesnt already have one?

 

[devinsixtyseven]

...The backpacker or motorcyclist approach to gear is a foreign concept to vehicle-dependent-explorers, who get stuck in the "if it fits, I'll bring it" mentality.

How many times do you see someone with 10 gallons of fuel, and 20 gallons of water, yet after 4 days they haven't needed any fuel and drive out with half the water reserves?...

All that extra camping gear, like a roll-up table, which is a handy thing to have - but what if you only use it for 2 hours and drive it around for 40 hours?...

I pay less attention to what I bolt onto my vehicle than what I put in it, although the bolt-on's need the same weight-to-use ratio philosophy. If you're not routinely in big rocks, why have 300# of massive belly skids, when a much lighter duty set would be sufficient.

...At the end of the day - was there really an obstacle that would have prevented you from reaching your destination solely because you have 32s and not 33s?

m.

That's some stellar advice there. The first long trip I took, we drove out with three unopened 5gal jugs of water! Getting a filter is much higher on my list now, there's no good reason to lug around 30gal (240#!) of water when you can drive in with two 5gals and filter as necessary. Leaves more room for toys! And steak and beer.

You're absolutely right about skid plates. Dimple dies can help that, but are expensive when it comes to pressing out the 3/16" plate most skids are made from. The holes also help with ventilation! There's a good chance that 300# of skids can be dropped to 225-250# with a set of dimple dies and careful planning. It doesn't just apply to skids either, anywhere that's flat exposed metal and can be reached with the press tool can fall victim to the dimple die .

-Sean

 

[goodtimes]

In my opinion, this would be your biggest problem/concern.

Maybe add a tranny cooler if it doesnt already have one?

Tranny coooler is good...so is a shift kit...but beware of warranty issues.

I do differ from Mikes statement to a point though. That roll up table, folding camp chairs, etc make life so much nicer. After years of using my backpacking gear (stove, water filter, etc) for camping....I finally broke down and bought some larger gear...and DAMN is it nice. Yea, I could travel lighter....but adding 50 pounds for some luxury is well worth it, IMO.

I also think carrying water and fuel may be justified...depends on where you are going. We all know that travelling in the desert s/w, you carry water, and lots of it. You never know where you will be able to fill up again, and what condition the water will be in. Same with gas if travelling south of the border. It was getting tight when we were heading to Bahia de los Angelos in '05. We lucked out when we found the Pemex open in Gonzaga Bay....I don't think I would have made it to BoLA....trips here in the states....chances are there is fuel around, and the quality is usually not in question...so carrying extra fuel may not be needed.

As to simply disregarding GVWR, be careful. We live in a country that is overrun by lawyers and sue-happy people (no offence to lawyers...). If you are in an accident and the person you hit decides to sue you...and comes to find out that you exceeded the GVWR of your vehicle....it is one more bullet they have in the courtroom, and we all know that punative damages are completely out of hand. Granted, the liklihood of that happening are pretty damn slim...but be aware of the possibility. Exceeding the stated design capabilities of a vehicle puts some liability in your lap.

Taking an honest look at the weight of aftermarket gear is good (as someone else suggested)...but to be honest, you are very limited with availability...there just aren't that many people making parts for Nissans. Plus, you need that stuff to be there when you need it. Skid plates are not designed for what you usually see on the trail...they are designed for what you usually don't see. Be sure that it will hold up when you really need it to....

As I have said before, and others have mentioned as well....the biggest thing you can *realistically* do when pushing the limits of GVWR, is to drive accordingly. Do everything slower....take off slower, stop slower, turn slower, drive down the freeway slower...do whatever you can to reduce the stress on the entire vehicle, particularly when off road.

 

[mike h]

I do differ from Mikes statement to a point though. That roll up table, folding camp chairs, etc make life so much nicer. After years of using my backpacking gear (stove, water filter, etc) for camping....I finally broke down and bought some larger gear...and DAMN is it nice. Yea, I could travel lighter....but adding 50 pounds for some luxury is well worth it, IMO..

LOL - It's just an observation - I don't always travel light - I have all that stuff too! The roll-up tables, kitchen gear to feed a (gourmet) army, massive cabin tent, inflatable beds, slew of 80 qt coolers... there are times when having a base camp that rivals a second home is most appreciated!

It's also a very different trip if it involves wives, kids and family members who aren't into 'roughing' it, versus a fast and light trip with a few friends.


but a the end of the trip I've become much more aware of those items that we didn't need, and try to remember that experience for the next trip. If for no other reason than to trade that space and weight for more steak and beer!


m.