Bear in mind the rear reinforcement bar is not a safety equipment. It is a repair reduction equipment for low speed <5mph collision.

The rear bumper material must be weaker than the actual beams it is mounted on. Otherwise it is worse to get chassis structural damage from the low speed collision.

The proper rear bumper has collapsible structure just like the front one. Gotta make sure UR product strength is just adequate, but not over. Otherwise good luck...

bumper designed to protect biker leg.

so hard, biker leg gg.


soft also for reduce impact

but chassis must be strong to protect the human inside.

open bumper not cun 1, you need to go up those machine and see from below. Those do professional chassis repair 1 they got laser beam, alignment equipment to check on the chassis straightness. Sometime u see straigh but whole body already like senget thus why some car you can see when driving the rear like sway to 1 side.

Well, I consider the rear reinforment bar as a safety equipment for selected vehicles such as MPV or hatchback. For a rear collision which involves say Perodua Alza if there are occupants sitting in the 3rd row, the risk of fatal injury is extremely high in the event of such collisions.



In the event of an accident major or minor, damage is already a certain case. It is better to have a damage to the chassis than a fatal injury to occupants where lives cannot be replaced. Chassis or whatever parts damaged can be replaced or scrap.

I'm just waiting for someone to point this out lol

This is because the beams (circled in picture below) themselves are not strong enough entirely, even put reinforcement bar will still collapse in.
Remember, if they make the 2 beams stronger... then reinforcement around B, C pillar need to be even stronger, all cost $$$

There's no way around it except get a different car model.



This post has been edited by constant_weight: Feb 9 2024, 10:18 AM

We don't have information on how strong is the structural frame of the car, or beams as you have put it so could you clarify how do you know the beams of a vehicle are not strong enough to support the additional rear anti collision beam?

hit one side, kena another side.
stiff dont absorb energy.
end up passengers suffering

We don't know, that's exactly the point.

Just as we don't know how strong UR bar is.

It is at your own risk.

Later low speed 10-15km/h collision, initially only need to repair bumper and trunk. Now become chassis misaligned, repeat wheel alignment also off.

Maybe no problem at all, who knows.

Now, I strongly against car marker for not installing the bar.

Only we need something proper design, structural calculated, at least in simulation.

If only UR can provide data, which I doubt.

If you don't have information on the strength of the main chassis or frame of the car, then it is incorrect for you to state that the frame is insufficient or not strong enough to support the additional anti-collision bar.

I'm not sure about automotive design but there will be parameters in the design which not only take into consideration the strength and weight of the materials involved but collision force which will vary with different impact scenarios. It's just a matter of having varied protection levels from low to high. Having a certain level of protection is surely better than none at all. Of course one can desire to have the maximum level of protection but the designer will need to take into account the overall cost of the vehicle as it needs to be economical to run (light) but at the same time a decent level of safety. A safe vehicle will usually be heavier due to thicker steel frame sections or some other reinforcement.

Since I'm typing on my handphone I try not to write too much. In my view, I reiterate for select vehicles such as MPVs which do not have any rear collision bars, it is surely much safer to have the bar installed than having none at all if there are occupants sitting in the 3rd row. It's a choice that a person makes, whether a human life is more important or your argument that the bar won't help since the frame of the car is not strong enough. The bar will surely help to a certain extent depending on the severity of the collision. Without the bar the impact of collision will be direct to the occupants sitting in the 3rd row, and if it's a strong impact things will just get worse. With the anti collision bar, the forces will be transmitted to the bar and to the main frame of the vehicle.

As for proper design and structural calculation, even though there are numbers, it won't be too useful as it will depend on the severity of impact as mentioned earlier, which is the force of the collision. To design to the worst case max scenario everything will need to be strengthened or beefed up which will add to the cost. The point that I'm trying to convey is very simple. It is better to have a bar take the direct force of impact rather than none. The question of whether the bar will be successful in operation, that is unknown since the force of collision is unknown but it will surely be safer with one than none.

Still don't agree??

This post has been edited by SportyHandling: Feb 9 2024, 07:11 PM

might as well put datsun absorber bumper lo.
碰碰車
i stay with u yes

and stop calling anti collision bar, it just a piece steel brace
u putting impact absorbing material much effectives to save humanity

Lol.... it is not I agree or not. I don't argue the need to have it, I argue only we need a proper one.

It is wether you trust UR do proper work of structural analysis you mentioned.

Do you? I don't.

Remember that is not anti collision bar. To be precise, that bar is the bumper itself.
The plastic bumper as we know in modern car is bumper cover.

Bumper is designed for low speed collision damage repair reduction. So your "anti collision bar" should deform on low speed collision, so the force not taken by the chassis directly.

The actual safety is built into chassis. The Alza MPV is just plain weak chassis. You put a hot formed, boron steel bar also collapse all in.

Again I against cut cost to eliminate the bumper. Better option is order one OEM from other market, or at least find 3rd party option made from aluminum with deformable structure.

Unless you trust UR. They have decent paint and welding quality, but not proper material structural analysis.

This post has been edited by constant_weight: Feb 9 2024, 08:54 PM

Just ask UR if they can provide this for their "anti collision bar" (which is bumper itself to be precise)

I rest my case 😌

I believe we are going in circles. You argue to have a proper one, which by your definition a collapsible design and an incollapsible design is not proper. I don't know about Ultra Racings design but have mentioned that even an incollapsible design is better than none.

Anti collision bar or strengthening bar sounds fine to me as it's still a bar. You can refer it as bumper as you wish. It's a trivial matter.

That's a useful analysis but how does that have an advantage over an incollapsible design in collisions of varying speeds in real life situations?

But x50 same platform got rear crash bar