Typically the passenger compartment is highly reinforced, and the rest of it is meant to absorb energy. I would expect that the strong passenger cage would also be stiff, and they could use the same materials and design tools to make sure it flexes in a desirable way. What I'm trying to say is they have the technology they need to make a unibody that can withstand off road use, even if current designs are not quite good enough. Jeeps aren't exactly known for great design or quality in my opinion, and I'm sure Toyota could do better. If fatigue isn't a problem for a ladder frame then it shouldn't be a problem for a unibody either.
Do you prefer BOF or unibody for 6th gen?
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Typically the passenger compartment is highly reinforced, and the rest of it is meant to absorb energy. I would expect that the strong passenger cage would also be stiff, and they could use the same materials and design tools to make sure it flexes in a desirable way. What I'm trying to say is they have the technology they need to make a unibody that can withstand off road use, even if current designs are not quite good enough. Jeeps aren't exactly known for great design or quality in my opinion, and I'm sure Toyota could do better. If fatigue isn't a problem for a ladder frame then it shouldn't be a problem for a unibody either.
BlackWorksInc
New member
First off, they do have the technology; that's why most every professional/hardcore off-road rock crawler/desert runner tends to be "unibody" in the sense that it's a full tube frame vs. Body on Frame.
Yes the cab is "stiffer" and more structurally sound against compression, rollover, and impact; but that does not translate directly to being able to be more robust when it's being twisted laterally and longitudinally. Those are forces not typically seen or expected in an accident, nor is on-road twisting/flexing as severe as you would see when rock-crawling. The stiffer you make the unibody, the less comfortable it will be on the road and the more effort and manufacturing you end up putting to make it handle like a BoF vehicle and less like a unibody.
You're statement regarding that if a ladder frame handles torsion and fatigue good, then a unibody should is flawed. The ladder frame is an entirely seperate section of the vehicle than the cab that bolts on top; it stands up to torsion and flexing so well because it's a very simple design that is strong but not overly rigid. When the frame twists, most everything bolted to it can give a little without causing issues; that's why the body is floated on the frame with rubber bushings. When the vehicle frame flexes that torsional force is not directly transferred to the body because it can wiggle on the mounts.
In a unibody you do not have that luxury, when one corner of the vehicle twists opposite of the other, the forces act on everything, from the suspension mounting points, through the body rails, and sheetmetal, ect. to the other corner in the vehicle (where as in BoF that's isolated into the ladder frame) Everything is attached and supported by the unibody, where as in the BOF the frame and cab are isolated from that type of torsion for the most part.
Depends on what you mean by capable, the thing I see most commonly is that after a certain point those unibody's need to be reinforced to survive. So then you start seeing owners weld/bolt in bracing, after that doesn't do as well they'll go full exo-cage that strengthens the vehicle further, ect. The point being that they have to had more and more reinforcement to the frame to have it be as robust as the BoF; from an enthusiast standpoint, that's just time and money and passion. From a manufacturer standpoint, that's a lot or research and development money and time into meeting a niche market; particularly when the majority want more "car-like handling" and less "truck-like robustness" that many of us on this forum expect from a 4Runner.
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Basically what I am saying is that to design a unibody to be as robust as a BoF, you'd end up putting more energy and effort to make it "truck-like" than it would be to simply go BoF; considering that the main goal of unibody is gaining that "car-like handling" it's sort of an either or issue, not really a compromise. A unibody out of the box does not typically stand up as well to repeated torsion and flexing forces that an out of the box BOF will; additionally it takes a lot of serious modification to get a unibody to be as robust as a BOF.
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i was referring to the 2012-present models that completely went away from a rugged suv to a Crossover/minivan style...aesthetically i liked all previous models of pathfinder
i spoke to soon without knowing which pathfinders had bof or unibody- i just meant that if toyota went to unibody on a t4r, then the styling would likely go away from what we all prefer as well as 4wd capabilities
Lester Lugnut
New member
mtvp
New member
The question becomes what will you do if it does become a unibody 4 Runner. Are you leaving to find a BOF truck? I hear you talking about the up side of the BOF. Will you succumb because you are a fanboy of the 4Runner ? Or vote with your money in some other choice ? I would guess that it would depend on what you really use the 4 Runner for and how much.
I think if you wanted a rock crawler. You would have a dedicated rig for such a thing. I see lots of lifted trucks that cost tons of money. They are like many SUV's that seldom leave the payment. They are for looking like they can be bad ass. They are just not sending much time in the wild.
So like many , I don't like the ever smaller pool of BOF SUV's left in the market place. It may be soon that pick up trucks are the only BOF trucks left.
Look at the way the industry is going.
I think if you wanted a rock crawler. You would have a dedicated rig for such a thing. I see lots of lifted trucks that cost tons of money. They are like many SUV's that seldom leave the payment. They are for looking like they can be bad ass. They are just not sending much time in the wild.
So like many , I don't like the ever smaller pool of BOF SUV's left in the market place. It may be soon that pick up trucks are the only BOF trucks left.
Look at the way the industry is going.
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I honestly think Toyota would not change it to a unibody design, because 90% of 5th gen owners I see on the road everyday are soccer moms, chances are that they dont care what type of frame the truck uses so there is no point in changing something that only a few will notice.
Unibody is better for soccer moms. It makes more interior space, and it might decrease the overall weight and size which would improve gas mileage. Those are the things soccer moms and Consumer Reports and the EPA care about. It could be cheaper to make, but I'm not sure. The Toyota Highlander is basically a less rugged unibody 4runner, and it's probably a better choice than a 4runner for a lot of people.
If I remember right, the 4th gen 4runner was one of the lowest rated vehicles in Consumer Reports, but I love mine, and most people here do too.
I guess it looks better when you talk about the interior space, I was thinking that I would like to see is an aluminum frame, that might solve Toyotas frame rust problems, but unibody would help that also. The rust is no problem for me or a lot of other members but I dont think that most other 4 runner owners break out the flap disc and kill that cancer
CookieRoe
Senior Member
I'm surprised no one has mentioned the next gen Lexus GX. It is practically confirmed it will be a unibody. I even talked about it a couple of years ago.
http://www.toyota-4runner.org/lexus-gx470-460/147448-its-official-next-gx-unibody.html
article: Lexus to replace GX SUV with new TX crossover
Wide consensus is that the Prado will live on in other parts of the world as a BOF vehicle. The next gen GX will become unibody to compete with Infinity's successful JX (now stupidly called the QX60). Lexus GS replacement will be called the TX.
What will become of the 4Runner? Nobody outside "Toyota Trucks Division" knows. I still say rebadge a Prado and ship it over, but AGAIN, what do I know?!
http://www.toyota-4runner.org/lexus-gx470-460/147448-its-official-next-gx-unibody.html
article: Lexus to replace GX SUV with new TX crossover
Wide consensus is that the Prado will live on in other parts of the world as a BOF vehicle. The next gen GX will become unibody to compete with Infinity's successful JX (now stupidly called the QX60). Lexus GS replacement will be called the TX.
What will become of the 4Runner? Nobody outside "Toyota Trucks Division" knows. I still say rebadge a Prado and ship it over, but AGAIN, what do I know?!
Gecko
New member
While I do believe that the GX will ultimately go unibody, those articles are nearly three years old.
Regarding TX name - note that most Lexus model trademarks include numbers - "LS 500, RX 350, GX 460," etc. So far, all that has been trademarked for "TX" is the name "TX." This is completely unlike any Lexus model trademarks.
Also note that Lexus has now trademarked and confirmed RX 350L and RX 450hL - longer, three row versions of the RX to compete with Infiniti QX60, MDX, etc.
More info on fabled TX and confirmed RX L here: https://lexusenthusiast.com/forums/...rx-crossover-formerly-rx-trademark-talk.1718/
paulndot
New member
If the Land Cruiser and it's Lexus cousin are any indication, Toyota may keep the 4Runner as a niche vehicle. The Highlander is similar in size and a unibody. If stealer ships guided customers right, soccer moms would be steered towards the Highlander, and enthusiasts toward the Runner. I'd be willing to pay more for the right type of vehicle vs a cookie cutter production. Nissan killed the Xterra and the Pathfinder might as well have died with it, as it's a mini van now. Toyota and Jeep seem to be the last holdouts in this size & style. I think it will all come down to a game of chicken - we'll see who blinks first.
Muzzle of Bees
New member
Currently there are plenty of unibody vehicles to choose from. Why bastardize this vehicle? Not many BOF's left. Toyota essentially has the market to themselves now that the Xterra is gone.
Gecko
New member
I don't have 2015 year end totals in front of me, but:
4Runner
YTD 2016: 15,972
Feb 2016: 8,476
Grand Cherokee:
YTD 2016: 28,544
Feb 2016: 15,380
Thai
Elite Member
Thanks...basically almost double 4runner. That may influence Toyota decision making. Although JGC is no better on gas, the future demands for fuel economy AND safety (aka crash test scores), Toyota may not have much choice but to go unibody.
And if Toyota goes unibody, then the next question is: will we lose the rear axle in favor of IRS?
I don't think this is true. Developing a body with very high torsional stiffness is a key priority for vehicle manufacturers. The stiffer the body, the better the suspension is able to do its job by isolating road impacts from the occupants. At the same time, it lets the suspension maintain performance when subjected to higher cornering loads.
The body still flexes. Get your 4Runner into a flexed position and try opening/closing the tailgate. It'll be "off" a little.
Interestingly, if the 4Runner remains the lone, BOF-contruction SUV moving into the future, the result may not be good for us as consumers. Consider the Ford Crown Victoria: Once GM stopped building their large BOF-sedans in the mid-90s, Ford enjoyed a monopoly an all things taxi cabs and police cars. From 1998 to 2011 there were literally zero changes in the Crown Vic, cosmetically and mechanically. To say Ford milked that cash cow for everything it was worth would be a gross understatement. As it is, Toyota is close to doing the same thing: Look how long the previous-gen Tacoma stayed in production, starting in 2005 with very few changes until the '16 model was released. People kept buying them because the Tacoma had very little competition.
BlackWorksInc
New member
I'm sure they do design with that in mind, but so far the number of spit weld issues, popping, creaking, and such I've seen in just corolla, Camry, Rav4, ect. not including some other models is not reinforcing me belief in that.
The cab will flex some, the frame mitigates much of that flex via the rubber bushings. If it were unibody, you might find the rear hatch won't close at all when flexed.
It would be interesting to see how well the tailgate opens/closes on a new JGC when compared to a 4Runner when placed in a similarly-flexed position. I'm optimistic that the modern JGC would perform much better in this regard when compared against an old XJ, whose design dates back to the mid 1980s.
I can't comment on newer Japanese vehicles but my E90 BMW felt like it was carved out of a solid block of steel. They aren't known for body issues. This being said I do know BMW has screwed up before - the older E46 M3 is notorious for broken rear subframe mounts.
