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Discussion Starter #1
First let me say that I am deeply saddened by the circumstances surrounding the recent Toyota FJ crash.

But for the future safety of our forum members. Would an aftermarket bumper in this case have made a difference? I'm just wondering what our forum member think on this. I've actually been contemplating an aftermarket bumber thinking it would improve the resilience of the FJ and be safer for my family. But in this case, a head on collision, I have no idea.
 

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Your guess is good as mine. You think the heavier, the better such as an ARB front bumper. Most people don't want to go that heavy. To what you are asking, are you hoping that the bumper act as a solid wall preventing the impact to move towards the main cabin? If so, then it affects the crumble zone in which the passengers in the main cabin takes the brunt of the force. This might be a case of no win here.
 

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I agree with above poster. I don't think an aftermarket bumper would have helped much with a head-on at that high a speed.
 

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Stock bumpers are designed to absorb the impact by breaking up, so does your engine bay. When you have a completely solid front end like on older vehicles the force of the impact is transfered directly to the people in the vehicle, so older vehicles have less damage in an accident but the passengers inside will feel more of the impact.

From what I know the bumper bolts straight to the frame, so it pretty much is an extension to the frame, so when you get hit it has to bend the frame out of the way before the engine bay absorbs any of the impact.

Think about as a cardboard box, if your holding it in front of you and someone hits it with a base ball bat it will break apart and take most of the impact force. If you put a metal frame inside the box and someone hits it again it will be like you are getting hit by the bat because the metal frame transfers the force.

It would be really hard to say if a bumper like this would save any lives, because at highway speeds a crush zone like the engine bay would not be able to absorb all of the impact and it could be lethal. If you had a stronger steel bumper it might absorb enough energy that it wouldn't be lethal. Also at slower speeds the original bumper may absorb all the impact and the people in the vehicle could be uninjured, but with an after market bumper everyone could have whiplash or worse.

The dynamics of a car crash are way to complex to just say one bumper is the best for everything or accidents like the one you mentioned would never be that bad. The bumper that is on your fj is determined to be the best bumper within reason ($ and practicability) for when it gets impacted as they test it. In reality if you change impact angles for a "head on" collision or read end the systems in place to protect you could end up doing more harm than good. If after market bumpers had extremal detrimental effects on car accidents they would be illegal for on highway use, there is really on right answer whether one is better than the other.
 

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Stock bumpers are designed to absorb the impact by breaking up, so does your engine bay. When you have a completely solid front end like on older vehicles the force of the impact is transfered directly to the people in the vehicle, so older vehicles have less damage in an accident but the passengers inside will feel more of the impact.

From what I know the bumper bolts straight to the frame, so it pretty much is an extension to the frame, so when you get hit it has to bend the frame out of the way before the engine bay absorbs any of the impact.

Think about as a cardboard box, if your holding it in front of you and someone hits it with a base ball bat it will break apart and take most of the impact force. If you put a metal frame inside the box and someone hits it again it will be like you are getting hit by the bat because the metal frame transfers the force.

It would be really hard to say if a bumper like this would save any lives, because at highway speeds a crush zone like the engine bay would not be able to absorb all of the impact and it could be lethal. If you had a stronger steel bumper it might absorb enough energy that it wouldn't be lethal. Also at slower speeds the original bumper may absorb all the impact and the people in the vehicle could be uninjured, but with an after market bumper everyone could have whiplash or worse.

The dynamics of a car crash are way to complex to just say one bumper is the best for everything or accidents like the one you mentioned would never be that bad. The bumper that is on your fj is determined to be the best bumper within reason ($ and practicability) for when it gets impacted as they test it. In reality if you change impact angles for a "head on" collision or read end the systems in place to protect you could end up doing more harm than good. If after market bumpers had extremal detrimental effects on car accidents they would be illegal for on highway use, there is really on right answer whether one is better than the other.
Since the aftermarket bumper bolts on the same place the OEM bumper does, it seems like the designed crumple zones wouldn't be much different. (I'm no engineer though). I agree with everyone that said that an aftermarket bumper would not do much different.
 

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There's this question that's been bugging me somewhat - would aftermarket bumpers make our FJs more dangerous should we accidentally collide into others?
 

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From what I read, both vehicles blew up in flames. So my question would rather be - What made the gas tank blow when it was hit in the front?
Is there a way to prevent the tank to explode?
 

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Since the aftermarket bumper bolts on the same place the OEM bumper does, it seems like the designed crumple zones wouldn't be much different. (I'm no engineer though). I agree with everyone that said that an aftermarket bumper would not do much different.
To address the OP, in that particular crash I do not see the bumper changing much.

The OEM "bumper" that bolts to the front of the frame rail is actually the first of many crumple zones. To install an aftermarket bumper, that is first removed.

Most all aftermarket bumpers use the plate and 4 bolts at the end of each frame rail as a mount and also tie back to the sides of the frame horns. Two more segments of the crumple zones are between the front mounts and where the bumper ties to the side of the frame.

So at the very least 2 o 3 segments of the crumple zome are deleted by an aftermarket bumper. Whether this is an improvement at all is hard to say.

My opinion is that for the task we use these bumpers for they certainly are a plus. Slow speed impact with trees and rocks are absorbed by these bumpers. You bet we in the interior feel it far mor than a stock bumper. Even on road I think I prefer a real bumper.

THe FJC is a typical modern vehicle, it is designed for the entire front end to fold up and absorb impact and protect the driver. In anything over 20 MPH you are looking at a full total of the vehicle in a great many cases. Not so with a steel bumper. I think the steel bumper is a "brige". In the event of a front end collision the bumper will take the hardest hit, if hit hard enough the crumple zones will fold.

Heck we have FJCs that are crumpling just from being driven around, fender bulges.
 

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The stock bumper is designed to absorb energy is small impacts and protect the frame and crumple zones, and to distribute the force across the frame in bigger impacts.

Here is what you could expect with a stock vs. aftermarket (steel) bumper:

1) Low-speed impact (below 5 mph) - stock bumper will absorb the energy 100%. There may be some visible damage to the bumper depending on the direction of the force and nature of the object you hit. Any necessary repairs will be modest. With an aftermarket bumper most likely there won't be any damage.

2) Moderate speed impact (5 to 20 mph). The stock bumper will absorb most of the energy, but there will be some damage to the front grill, hood, etc. Most likely there will be no damage to the frame, so the repair costs will be manageable. On the other hand, with an aftermarket bumper that does not absorb energy very well, it is VERY likely that there will be extensive damage to the frame, and the cost of repairs will be much higher. The energy HAS to go somewhere and it will be dissipated by the weakest link in the chain.

3) High speed impact - there probably won't be much difference, as long as the aftermarket bumper is designed properly.

The function of the bumper is two-fold:
a) to absorb energy in a small impact
b) to distribute the energy to the frame in a high speed impact.
The aspect of distributing the energy is a very important one. The purpose is to use all available structural strength of the car to uniformly absorb and dissipate the energy of the impact. It takes many hours of engineering, including some high level of dynamic FEA simulation to get it right. I doubt that aftermarket manufacturers have the time, money and engineering skills to perform such analysis.

As a side note, this is what makes big difference in crash test rating between European and American cars. The standard NHTSA test is a full-frontal test in which the car is crashed into a perpendicular concrete wall. While this creates a huge deceleration, it makes it "easy" on the designers of the bumper, because the force is by default uniformly distributed over the entire frontal area of the vehicle. On the other hand, the European test (and the one performed by IIHS) is an offset test, that covers only 40% the vehicle's front. This makes the design of the bumper and front-end of the car much more critical. Traditionally American-designed vehicles would score well in the NHTSA test, but would do poorly in the Euro test. On the other hand, any vehicle that score well in the Euro test, will easily score well in the American test. Japan uses both tests to assess their vehicles.

Net, if what you care about is small dings and repairs when off-roading, an aftermarket bumper is a good choice. But if safety is your priority, you are probably better of with the stock bumper.
 

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Not much will help you in a head on collision at those speeds (except mass).

Most of the comparisons I am seeing in this thread are sort of assuming you are hitting something immovable (or moves very little).

Basically this is the conservation of momentum.

When 2 vehicles collide the reaction is a bit different. A steel bumper might be taking away some of the energy dissipation if you reduce one of your crumple zones. However, it has to go somewhere, I would suspect some of it would get transferred to the other guy (assuming about equal masses).

The accident does sort of one concern I have with the FJ design. If you are in a collision and the front doors are jammed shut, it will be tough to get out. Especially in the back.
 

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I'm not sure if it contributed to the fatalities of not, but the rear doors of a FJ have a serious design flaw, in the event that the front seat occupants are incapacitated the rear doors can't be open without climbing thru the front. In the event of a fire that could be fatal.
 

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Just a thought but if your stronger steel bumper which most are rated for off road use damage another vehicle can your insurance company deny coverage? If you kill someone because you changed or deleated the crumple zones can you be criminally liable? I have no idea just curious? I see a lot of really tall trucks in my city that could drive over a car if they were to rear end someone. Makes you think doesn't it?
 

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Another reason we passed on the oh so cute Miata.
 

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I've heard figures that at those speeds 99% of people die on impact and more pass on within a couple of hours after the collision.

I have no proof of these figures but believe them.
 

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Just and FYI:

The ARB bumper is the only one on the market with a built in crumple zone bracket designed to reduce the impact in a high enough speed crash.

But, FWIW, i don't think any kind of bumper out there could have saved the folks in that collision.
 

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This could be debated forever. I'm sure it's been analyzed on the Jeep forums?
 
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