Wreckers!!

[JohnDeere8530]

Yes , A car doing 50 mph running up the back of a lorry would have a vastly greater amount of energy than a lorry reversing into a loading bay and hitting a wall. By the tune of about 5 fold my guess would be. You underestimate how much energy is actually contained in a speeding car, far more than a lorry reversing at a slower pace

What im saying is The design of these rear ram bars are inadequate to stop a fast moving car, the spec of them is more akin to act as a nudge bar when reversing. I agree this is wrong; however design limitations prevent it from crumpling when hit fast

Remember the energy stored in a moving system is proportional to mv^2. Ie a 44 tonne lorry reversing at say 5 mph would have around 1/5th of the energy of a car travelling at say 50 mph

 

[roscoe erf]

To stop people driving under them.

no no no they are not design to stop cars they are there to deflect pedestrians and cyclists from going under the rear wheels

 

[Lincsman]

FFS its an under run bar not a bumper;
http://www.transportsfriend.org/road/underrun.html

Every device fitted to a vehicle in compliance with the requirements of regulation 49 shall at all times when the vehicle is on a road be maintained free from any obvious defect which would be likely to affect adversely the performance of the device in the function of giving resistance in the event of an impact from the rear.

 

[JohnDeere8530]

not really as theyre not up to the job, think you are missing the point lol

Have a look sometime, most are of light box section steel (so lorry can carry more weight) and are only any good as a bumper bar when the lorry is reversing

 

[Mursal]

The lads on the fire engine earned there keep cutting into the Golf, not much room with someone in the drivers seat .........

 

[roscoe erf]

most rear bumpers are just that bump ers they are of no real strength or weight most are light box or u section 2/3 mm at best if you expecting to rear end a lorry and be saved by the under bumper good luck with that they are designed to absorb some of the impact but not much had to beef mine up used 6mm wall box and some 8mm plates now she won't move in a hurry but i hate to be the jam in that sandwich

 

[onthehoof]

side guards are mainly there to stop pedestrians and cyclists going under. It would be difficult to make them strong enough to stop a car.

A car travelling at 50mph hitting a lorry has a massive amount of energy, any guard would simple break off. Rear guards you see are mainly bumpers to stop damage when a lorry is reversing into a loading bay etc, where energy levels are small compared to a speeding car

Isn't the point that when a car hits the rear bumper the cars safety mechanisms i.e. Air bags are triggered,whereas without the bumper it's more than likely to take your head off. Surely a car driver stands more chance of surviving if the first impact is on the car bumper than an RSJ 6 inches from the drivers face

 

[roscoe erf]

http://www.dailymail.co.uk/news/art...ples-house-dramatic-proposal-Netherlands.html

 

[CORK]

http://www.dailymail.co.uk/news/art...ples-house-dramatic-proposal-Netherlands.html

Must have been a big lad....

 

[JohnDeere8530]

Must have been a big lad....

looks like the crane driver didnt fully extend the rear leg that's on the load side. I'm guessing its due to the parked car being there !

 

[Kevtherev]

 

[CORK]

View attachment 89112

wont be minimal disturbance now!!!

 

[L P]

View attachment 25894

Was that John Jones' tractor?

 

[roscoe erf]

Was that John Jones' tractor?

i don't know

 

[rc mx110]

http://www.dailymail.co.uk/news/art...ples-house-dramatic-proposal-Netherlands.html

Then they droped it again trying to lift it

 

[BobGreen]

most rear bumpers are just that bump ers they are of no real strength or weight most are light box or u section 2/3 mm at best if you expecting to rear end a lorry and be saved by the under bumper good luck with that they are designed to absorb some of the impact but not much had to beef mine up used 6mm wall box and some 8mm plates now she won't move in a hurry but i hate to be the jam in that sandwich

They must have some strength as we sometimes pick up empty trailers with loadall to get them out of tight yards

 

[JohnDeere8530]

They must have some strength as we sometimes pick up empty trailers with loadall to get them out of tight yards

But the force involved is miniscule compared to an impact by a car, it amazes me how many dont realise just how much energy a rapidly moving car possesses Looking into this subject on the net, the law makers tend to agree that these bars arent fit for purpose (ie stopping a car from going underneath) although they are ok for when a lorry backs into something. Therefore there are new regulations about to come into force. Of course being in the UK there are pages upon pages of consultations on it

 

[Dragline]

Can say from experience the bumpers on all our tankers will stop a car from going under them. The forces exerted on a bumper by a dead stop impact are astronomically larger than the forces excerpted when lifting it off the bumper to move it out of the way. The person in that car is dam lucky to be alive. Last accident I saw like that still gives me sleepless nights

 

[Renaultman]

Yes , A car doing 50 mph running up the back of a lorry would have a vastly greater amount of energy than a lorry reversing into a loading bay and hitting a wall. By the tune of about 5 fold my guess would be. You underestimate how much energy is actually contained in a speeding car, far more than a lorry reversing at a slower pace

What im saying is The design of these rear ram bars are inadequate to stop a fast moving car, the spec of them is more akin to act as a nudge bar when reversing. I agree this is wrong; however design limitations prevent it from crumpling when hit fast

Remember the energy stored in a moving system is proportional to mv^2. Ie a 44 tonne lorry reversing at say 5 mph would have around 1/5th of the energy of a car travelling at say 50 mph

I'm really sorry but they really are there to protect car drivers and the rubbers on the loading deck are to protect loading bays. They aren't there to stop a car in so much as to cushion the impact.

 

[Jon Feetham]

I'm really sorry but they really are there to protect car drivers and the rubbers on the loading deck are to protect loading bays. They aren't there to stop a car in so much as to cushion the impact.

Agreed, I think of it as a crumple zone for the trailer.