FrigginFGO

Many of us think of safety differently:

Scenario:

It's the coldest day of the year and the road has patches of ice. Hours from home the unibody vehicle get's into a collision getting totaled in a process. Airbags are deployed and the family is safe. The police report is done and the officer goes to other calls. Friends are contacted but it will be hours before they pick the family up. The family is freezing because the collision made the heater not work. You are waiting for the tow truck to tow your vehicle, but it will be awhile before they get there because they are working on other accidents in the area. When they eventually arrive, the tow truck only has room for one other passenger in the cab and none for you family.

A body on frame vehicle in the same scenario has a better chance of not getting totaled by it's design thus giving the family a chance to get to the nearest gas station or restaurant for warmth.

I'd rather have a vehicle that can get my family to safety than be stranded somewhere. You never know what kind of environment a collision will occur.

Lolrax

I hear you on that example for sure. I like having a body on frame 4X4 because I like to be prepared for the worst no matter what that is. Even if the worst is traffic and I need to crawl over a high median

Quadro

There is another point of weight. The body on frame vehicles are heavier which means they're going to generally over power most compact cars. If my GX collides with a compact unibody car the GX might have zero crumple zones for all I care because it's just going to throw the car away. I have a friend who collided in his Land Cruiser 100 with a mid-sized sedan. The sedan was thrown off the road and onto the woods and was totaled, the Land Cruiser stayed on the road and drove home by itself.

The body-on-frame vehicles started adding crumple zones in front and the back of the vehicles, attached to the main frame so they don't compromise rigidity or durability. But from the crumple zone perspective alone unibody's are easier because the entire body can be designed to crumple.

caha14

I know this discussion got rather spirited in a different thread...

All I will say is that I am more comfortable with my family riding in a BOF: LX570 currently, GX470 prior to that. Yes, it is heavier, it has a high center of gravity and it loves gas, but I do believe it does a better job of protecting my family. Further, shall the snow plow make a mess at the end of the driveway on a nasty day, my vote is on the LX getting in before - say - an RX, especially if my wife raises the suspension on all four corners.

T4Fun

ahh, the LX is the king of all suvs, hands down. dont care what anyone says...
your lx frame has more ladder cross members than our gx frame, making it a little stronger..

why couldnt toyota just make a mini lx frame for our gX?

bof is generally safer than most cars except the tesla model S, which is far stronger than any bof vehicle out there. its made of aluminum, and so strong it broke a test crash machine...
all car manufacturers should learn from tesla on how to make a real frame for a vehicle...

Koz

Unibody design uses the body as the frame. When one part of the body flexes all the other parts flex also. In time, these constant stresses affect the long-term durability of the vehicle. With a body on frame (BOF) design most of the flexing is limited to the frame itself, not the body. The point I want to make is yes, unibody vehicles can be designed to be capable but they are not as durable as BOF. This is why BOF vehicles are better suited for utility work (heavy duty hauling, off-roading and towing) and why you still see this design still being used!

Koz

T4Fun

well, except the fire noted yesterday which dropped the stock big time

Toys4RJill

Interesting points and discussion you have created. But I don't think you are any safer in a body on frame vehicle versus a unibody vehicle. There is a perceived safety that many owners believe is true.

Looking over the only real data on the subject and that is crash scores. There a lot of body on frame vehicles that did not perform as good as the body on frame.

A few examples , the Honda Ridgeline crash score better than a Tacoma, Mercedes ML scores better than a 4Runner. And the Hummer H3 is aweful.

IMO crash engineering is more important.

Quadro

The problem is that NHTSA test are done assuming collisions with a static object infinitely heavier than a car. How many real-world collisions are like that? To make a point - a dump truck can have a rating of zero and Tesla can have the highest rating in all the categories but when Tesla collides with a dump truck the highest crash rating of Tesla doesn't mean it's safer to be in a Tesla than in a dump truck.

SW17LS

Do you have some source or proof to back that claim up?

Compared to an RX sure, but what about a Range Rover? Thats far more comparable to your LX and Unibody.

Your LX is more capable than an RX because its heavier, has more ground clearance, and has a far more sophisticated 4WD system...not because its BOF vs unibody.

+1 Also to add what I said in the other thread, airbag deployment has NOTHING to do with the degree to which the vehicle is crushed in an accident. If you have an accident in a BOF vehicle or a unibody vehicle, if the deceleration forces are the same both vehicles will deploy the airbags regardless of which one sustained more damage. Since BOF vehicles are designed to crumple in the event of an accident also, there is no reason to believe that a BOF vehicle would be more likely to start and be drivable than a unibody vehicle in the OP's scenario.

FrigginFGO

The best example is the Mitsubishi Montero when it switched from BoF to unibody over a decade ago as was discussed in the other thread. It was an affordable vehicle that even the average joe can buy. It was also extremely popular in it's BoF form. It went unibody in 1999 and ceased to exist in the U.S. after 2006. It's been almost 8 years since the last model year and you rarely see the unibody version on the road to this day. But it's BoF predecessor is still around in decent numbers on the road. Unibodies will fail the test of time.

SW17LS

There's a lot more to a situation like the Mitsubishi Montero. First off, when Mitsubishi went unibody with the Montero it raised the price significantly. Mitsubishi was competing with luxury branded SUVs and the market just wasn't there for that. The vehicle was also very avant guarde at the time. Mitsubishi has failed overall as a brand in the US. As to the test of time...I would say Toyota/Lexus makes a much more solid and reliable vehicle than Mitsubishi, look at all the RXs still on the road from the late 90s.

Even if your argument that BOF SUVs hold up better with off-road use were true, seeing that 95% of SUVs never see any kind of use a car doesn't, why would you assume unibody SUVs would not "stand the test of time"? Plenty of unibody cars still out there "standing the test of time".

Using the Mitsubishi Montero as an example of why unibody SUVs aren't capable is like saying tablets will never stand the test of time because BlackBerry's failed.

T4Fun

there shouldnt be any flexing at all on the ladder frame itself. might as well be cUv then.

unit bodys do have to flex with road surfaces, but going off road stresses it more since then the tires are not all in same plane. this is simple physics. Manufacturers try to minimize this and make it more rigid by placing more spot welds. there is no data needed for this.

Toys4RJill

There absoletely no reason to believe a body on frame vehicle will start, and if it were the case of an accident, for safety concerns you wouldn't want the car to start anyway.

Now, for anyone who is interested. Check out the data from www.mynrma.com.au. test data from there show pics and the data.

The Land Crusier without knee air bags was rated as 4/5 , A Hyundai Santa fe got 5/5 in the same test.

For those who believe in the false promise that a body on frame will hold up better in a crash need to see the pics and the data.

A VW toureg looks like it held up better than a Land Cruiser and that is just by looking at the pics. Even a Volvo station wagon looks like it held up netter than the 2012 Land Cruiser.

There is more to safety than whether the vehicle is body on frame, the 70 series Land Cruiser received 3/5.

The most important thing to vehicle safety is engineering, if the manufacturers want a vehicle to survive a crash then they can make it happen, the more they put into the design, the more it will survive.

As for what will last longer, the consensus is that a body on frame will, but if anyone has ever seen manufacturer data, the manufactures know exactly when a part or system will fail. It is all on the testing and engineering of the vehicle.

Koz

Both types of frames have to flex otherwise there will be serious chassis and structural failures. There are also advantages and disadvantages to both types. Both types can be designed to be as rigid as needed. The difference is that each has inherent advantages that are considered for a particular application. The auto manufactures like unibody mainly due to the fact that it is cheaper to make and helps reduce weight (lighter), while providing a quality ride. The enthusiast likes BOF because it is easier to modify and repair. This is where longevity also comes into play.

This comparison is just like many other automotive debate about which is better.

Is Mobil 1 better then Amsoil?
Is 0w-30 viscosity better then 5w-30?
Are Michelin tires better then Bridgestone?
Are ceramic brake pads better then semi-metallic?

This can go back and forth forever!

Koz