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Death of the body-on-frame SUV?



  • jim314jim314 Posts: 491
    How are body on frame SUVs safer than unibody SUVs of the same mass?

    The body on frame SUV is stiffer (less crushable). This doesn't mean it is safer in all types of collison. In fact in a single vehicle collision with a very stiff obstruction (tree, concrete wall, bridge, etc.) the extra stiffness of the body on frame will cause higher crash forces to the occupants.

    In a two vehicle collision between vehicles of unequal mass, the occupants of the more massive one experience proportionally lower crash forces, and the occupants of the less massive one proportionally higher forces.

    If you have to do serious towing or hauling, then the pick-up based RWD SUV is the best for the job. But these massive high powered vehicles consume fuel at a higher rate, which is a threat to our economic future.
  • explorerx4explorerx4 Central CTPosts: 12,152
    traverse v6 (cuv) has a curb weight about 100 lbs more than a trailblazer ext v8 (suv).
    it is making an assumption that the the 'frame' of an suv is not designed to handle a collision in any manner different than a cuv.
    2017 Ford Fusion SE 2014 Ford F-150 FX4
  • bobw3bobw3 Posts: 2,992
    "putting your family's safety before that of complete strangers"

    Actually the "strangers" I'm thinking about are my brothers, sisters, aunts, uncles, cousins, neighbors, co-workers, etc..., who actually mean something to me, but then you're more concerned with yourself and the dog sitting beside you...hmmmm. And yes I know that anyone who thinks of others is called a "socialist."

    Now let me go back to my Prius forum with rest of the socialists ;)
  • jim314jim314 Posts: 491
    The real heart of the matter is that people who drive heavy, stiff vehicles shouldn't be castigated as totally unconcerned about the safety of the occupants of other vehicles.

    And people who drive body-on-frame SUVs shouldn't claim that those who drive more fuel efficient and less menacing vehicles don't care about the safety of their family or other occupants of their vehicle.

    It's a continuum. These are all legal vehicles. But the fact is that the era of cheap petroleum is coming to an end. To preserve our economy and our natural resources we may have to enact tax policies that discourage the discretionary high consumption of petroleum.
  • bobw3bobw3 Posts: 2,992
    "These are all legal vehicles"

    Just because something is legal doesn't make it smoking in offices was legal even though at the time the 2nd hand smoke was killing co-workers, but it took years for the legal system to catch up with what was right. Car pollution standards that were legal 30 years ago that made the air unbreathable in many cities are now illegal. Again, it takes a long time for the legal system to get in line what society feels is the right thing to do.

    Obviously people can drive whatever legal vehicle is out there. My point is not to castigate everyone drive a giant SUV, but just encourage them to think outside their box... My hope is that MPG standards will get so high that manufacturers will have to reduce the size of vehicles they produce just to meet the MPG standards. That will create the twofold benefit of less gas usage and less big cars competing wtih the small ones.
  • tidestertidester Posts: 10,059
    but just encourage them to think outside their box... My hope is that MPG standards will get so high that manufacturers will have to reduce the size of vehicles

    That's not encouraging people to think outside their box, that's forcing them into yours. But I still think we should relegate the political discussion to another venue. hint, hint!

    tidester, host
    SUVs and Smart Shopper
  • wlbrown9wlbrown9 Posts: 867
    I'm waiting for the Plug In Hybrid extended range SUV/CUV. One of these would cut my petro usage about 75% and NOT require that I downsize. 50 to 100+ MPG would be easy for me with an average daily comute of 40 miles. -washington-dc
  • dieselonedieselone Posts: 5,727
    I really don't want to get into a pi$$ing match over how evil SUV's and their owners are, but I don't care what anyone drives or what others think of what I drive. I've had several SUV's over the years because I choose to tow a boat and a travel trailer. Plus we often bring our daughters friends along so, I occasionally have 6-8 people in the Expe. I like the SUV over a truck because it has a much better suspension for everyday driving, plus the extra room for passengers. But if the "high and mighty" econo car crowd win and make the SUV extinct, I'll just buy a diesel 3/4 ton truck and continue to use my boat and RV.

    As for dangers on the road, obviously, I understand the physics of my 6000lb SUV broad siding a Civic. But, if a larger SUV like a Expedition/Tahoe/Suburban are so dangerous, how come they are so cheap to insure? I pay less than $60/mo on my 07 Expedition for full coverage with a 500k liability policy and $500 deductible. You'd think if the actuaries could prove that my driving a 6k lb SUV would mean I'm more likely to kill a family in a compact car, my rates would be much higher. I'm paying far less than I did for any car, and I have more liability coverage than I did then.

    I did T-bone a person in a Grand Am with a Nissan Pathfinder about 6 years ago. I hit them right on the drivers door. I was going about 30mph (I was in an unfamiliar area and didn't see the stop light until I was basically in the intersection and it was raining (no question it was my fault). My air bad did not go off and she walked away unscratched. Did total her car though and did 7k damage to my 01 Pathfinder. You'd think by listening to this board, my accident should have killed the poor lady I hit.
  • rockman59rockman59 Posts: 250
    Luckily large body on frame SUVs are selling less every year, so you're right Americans are making their choices, and more smartly now too for everyone.
    That may be true but I just read an article yesterday saying that the dealers are selling every SUV and pickup on their lots. Supply is short because of the GM/Chrysler situation. Likewise, the prices on used Suburbans, etc are on the rise again.
  • Jim,

    It’s easier to control the rate of deformation of a uni-body vehicle than a full frame vehicle, which is probably a good thing in a low speed impact. Taking the Chevrolet Traverse, which someone earlier said does not have a frame. The weight listed on the Traverse is about 5,000 pounds. According to a certified “CAT” scale, the weight on my Expedition with a full tank of fuel and me in it is right at 6,000 pounds. In a collision with a stationary wall at 40 mph, the Traverse has lower crash forces transmitted to the driver than the Expedition, but this is with the vehicle striking a fixed object. Both vehicles are rated five stars for the frontal crash into the wall test. If the Expedition and Traverse hit each other in a head on collision at the same speed say 45 mph, the Expedition driver will incur lower crash forces because of it’s heavier weight than the driver of the Traverse. Additionally, if you look at the Traverse side collision numbers on you will see that the Traverse has worse numbers than the Expedition but still garners a five star side crash rating. Where the full frame vehicle comes into it’s own is in a severe two vehicle collision. Remember, in a frontal type collision, you want the front of the car to deform as much as possible up to the point of intruding into the passenger compartment. Some of the newer full frame vehicles have dimpled or weakened portions of the front part of the frame to help with deformation in a frontal collision. Remember that crumpling is good up to a point then you want deformation to stop completely, again before any intrusion into the passenger compartment occurs.

    Framed vehicles such as full size SUVs and full size pickup trucks are built on a heavy steel frames so they can handle heavy loads. I’m not sure we will see the death of the body on frame vehicle because there will always be a need for a vehicle that can haul a five-ton trailer such as a boat, camper etc. and that takes a steel frame vehicle. Nobody will argue that heavier vehicles don’t have a huge safety advantage over smaller lighter vehicles in a high crash force accident. A strong steel frame just adds a greater degree of protection from intrusion into the passenger compartment. There will always be accidents that are so severe that no vehicle would offer sufficient protection.

    By the way I found this video from IIHS (Insurance Institute for Highway Safety) which is worth watching:

  • jim314jim314 Posts: 491

    Very interesting info about the results of your T-bone crash. . . It's very surprising that your airbag did not deploy. Even more amazing that the woman in the Grand Am walked away--truly miraculous outcome for her and you.

  • bobw3bobw3 Posts: 2,992
    Sorry HOST, but with the forum with the title, "Death of the body-on-frame SUV?" I would think there would be some leway in the discussion, especially since I don't see hardly anyone here talking about the death of body-on-frame SUVs too much, just people talking about why they want to keep theirs.

    And I don't see how I can "force" people to think one way or another just by posting here...I don't think my words here have that much power ;)

    But posting an opposing view in this forum is like going to an NRA forum and posting the obvious truth that if there were no guns available, then there would be no deaths from guns...but no politics right :surprise:
  • dieselonedieselone Posts: 5,727
    With upcoming CAFE regs I can see BOF SUVs going away except for maybe a Suburban and/or Expedition EL. I imagine Ford and GM probably will keep current designs around a while. While I'd hate to see the Expe and Suburban go away, it wouldn't be the end of the world. I'd just get a pickup to tow my toys.
  • explorerx4explorerx4 Central CTPosts: 12,152
    um, stay away from the head on into the wall.
    my bof after meeting a wrong way driver
    2017 Ford Fusion SE 2014 Ford F-150 FX4
  • hoss416hoss416 Posts: 1

    This might upset you but I have a 3/4 Ton Diesel P/U and a SUV. I just sold my VW to pick up the SUV too! Why would I want to do this, for a couple of reasons. While we are a pain for you to see around the added height gives us the ability to see further down the road to avoid danger, if you are at a proper following distance you too should be able to react in a timely manner. On week ends I like to spend time with my family and friends, when we go out it is nice to fill the eight seats in my SUV and take one vehicle over two, thus reducing the amount of vehicles on the road. Finally I enjoy being able to pick up my furniture, mattresses, and other bulky items myself and avoid the delivery trucks, which are much more difficult to see around and get far worse mileage than either my P/U or my SUV.
  • I challenge the auto makers to develop a 50-mpg or plug-in electric with fast-charge battery counterpart to our work-horse SUVs! I have a 1990 4WD, 6-cyl, automatic, Isuzu Trooper that I have used twice to move across California and back, evacuate twice to escape wildfires, enjoy desert jeep trails for hikes not accessible to 2WD, low-slung cars, haul picnic, beach, tail-gate party, gardening and home repair supplies, cat and dog in carriers, and of course passengers. This has been the best car ever, because it's comfortable enough for road trips and provides good visibility, off-pavement and load-carrying capacities. I save gas now by living close to work and consolidating errands but would like to do more traveling again. I'm considering cash for clunkers and wish there were a fuel-efficient or electric alternative. Instead of demonizing SUV owners, challenge the auto makers to design an environmentally friendly replacement; and I don't mean SUV cross-overs or hybrid station wagons weighed down with a 3rd-row seat.
  • bobw3bobw3 Posts: 2,992
    What model SUV did you buy?
  • I have to occasionally haul full sheets of Plywood. I occasionally pull travel trailers and utility trailers. And I regularly have 6 or more people sitting in my 2008 Expedition. When we have a group going out to dinner, we take 1 car instead of 3. I am also getting a little over 15 MPG around town, and 20-21 on the highway.

    I have a tax client with a diesel Excursion. Combining their families, they have 6 kids. Seems like a no brainer to me. She is the neighborhood sports drive, so I seldom see it without at least a half dozen people in it.

    Another client was bragging about trading in his 2 year old Suburban on a new Honda Civic and how he was saving $75 per month on gas. It was his wife that mentioned that their car payment is $150 higher each month because the trade-in amount was lower than their balance due. And they regularly have to rent a pickup for $100+ to take the boat to the lake for the weekend, and take the car because the truck doesn't seat enough people.
  • Well it happened. I was involved in a minor accident. Yes it was the first accident I have been involved in that was my fault in over 30 years of driving. I was turning left at an intersection in my 2008 Expedition (full box frame vehicle) and collided with a 2008 Honda CRV (unibody). I was doing less than 10 miles per hour. The other vehicle had slowed down and was probably doing less than 20 mph. Both of us turned to avoid the accident. Airbags did not deploy in either vehicle and no one was hurt. The Expedition is approximately 2,500 pounds heavier than the Honda. Naturally the Expedition came out better. The radiator, engine and transmission on the Honda was turned completely off axis and was shoved into the Honda's firewall. The Honda went through the Expedition's cosmetic pieces like the fender and bumper cover but once it hit the Expedition's frame, the Honda didn't go any further. The Honda would not move and had to be winched onto a flat bed wrecker and hauled off. I drove the Expedition for a week until I had time to get it into the body shop. I'm not sure if the Honda was totaled or not but I would not be surprised if it was as it had some major damage not only to the body/unibody but also to the entire drive-train of the Honda. The main thing here is that nobody was injured. Had the same collision happened at higher speeds, it wouldn't have been pretty for the Honda. Again, thank God nobody was hurt.
  • bobw3bobw3 Posts: 2,992
    It's good that vehicles are getting smaller and safer in general so when accidents do occur the outcome will be better for all involved.
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