[designersf]

Originally Posted by FlyingSpur

Would you rather fix a bumper or a metal body panel after an accident? Aren't plastic parts much cheaper to repair than metal parts? Then again, dent work on a metal panel may be cheaper than replacing and painting the entire bumper in case of a crack. Hmm, I'm undecided here. Only actual figures will tell.

Good thread. Being a person involved in this field, I do know that the reason for bumpers getting bigger are due to stringent pedestrian impact regulations (they need to be saved at any cost). And like Flyingspur mentioned (a very important point), would you rather pay for metal re-work or live witha a small dent/crack in a plastic part? It is not cost cutting but rather cost-saving to the customer. In case of a fender bender in the amby, you would need to re-work the entire metal bumper and bodywork while in new-gen cars, its just a matter of changing the bumper or living with the dent. Moreover, bumpers these days are designed to withstand 5mph impacts. Now can a metal part boast of the same?

And with respect to paint quality, bumpers meet the same standards as body metal. So there is no difference in quality as such. However, sometimes the colour tone on bumper is different to the body (due to the plastic) and that's about it.

[mdsaab]

very interesting observation.
as mentioned below i feel it is due to the safety norms that most manufacturers have to adhere too.
many models sold in India are global ones.
So these new design philosophies aid in getting better safety scores such as Euro Ncap, as well as pedestrian safety which i think is a part of Euro Ncap ratings too, if i am not mistaken.

[vina]

Originally Posted by MileCruncher

Absolutely agree. But that is performance engineering plastics. I'm not sure how many of A/B Segment car owners will be willing to pay the added costs.

everybody wants cheaper cars right

There is a notion that "performance engineering" is pricey. Sometimes (i.e. most of the time) the opposite is true - providing acceptable quality (read high) at reasonable (read cheap) is damn good engineering.

Regarding bumpers - if the requirement is to save pedestrian's limbs then whether you want the bumpers to be stiffer is questionable. This is similar to having stiffer car chassis vs. having crumple zones (which one is desirable trumps any discussion on cost)

Keep in mind that strong and stiff are not the same thing. For the same weight and thickness a spider web is stronger than steel wire - that doesn't make the former stiffer or harder than steel (you can replace "spider web" with "carbon fiber" and read the statement again).

As someone has mentioned already, these bumpers are strong enough and cheap enough already.

[dot]

Few years back I had witnessed an Indica tear down which tried to look at plastics that go into various components. The bumpers were made of PP/talc or PP/GF, dont remember exactly. I dont think anyone can rate such materials as pedestrian friendly due to high stiffness (high modulus). Nowadays many OEMs are using rubber particles/rubbery plastics to make better bumpers which match with standards. This works.

Can they be bettered, in terms of design and material choice (gradiant foamed materials etc)? For sure. But that involves cost, as I understand.

[dhanushs]

Originally Posted by vina

Regarding bumpers - if the requirement is to save pedestrian's limbs then whether you want the bumpers to be stiffer is questionable. This is similar to having stiffer car chassis vs. having crumple zones (which one is desirable trumps any discussion on cost)

Originally Posted by MileCruncher

As about cost cutting, I don't think there is much scope. One can make slightly heavier and thicker bumper but that would mean changing the overall design, increasing weight, reducing FE et al.

Hi,

Rather than having stiffer bumpers, I would prefer my bumper to have 'shape memory' properties. ie, on the even of slight collisions, they just reform into their molded shape. I guess, even manufactures prefer the same.

But isn't the cost factor preventing them from doing so?.

[lucifer1881]

Originally Posted by FlyingSpur

Would you rather fix a bumper or a metal body panel after an accident? Aren't plastic parts much cheaper to repair than metal parts? Then again, dent work on a metal panel may be cheaper than replacing and painting the entire bumper in case of a crack. Hmm, I'm undecided here. Only actual figures will tell.

Metal! Insurance only covers 50% for the plastic parts but almost 90% (depending on the age of the car) for the metallic parts. When you claim insurance, work on metal is definitely cheaper to the car owner than replacing plastic parts - 100% coverage on denting and painting labour.

Unless the insurance companies in India stop depreciating plastic parts by 50%, I want metal bumpers. They are the most often damaged parts of the car and I do not wish to spend money replacing them.

[RaguHolla]

Originally Posted by lucifer1881

Unless the insurance companies in India stop depreciating plastic parts by 50%, I want metal bumpers. They are the most often damaged parts of the car and I do not wish to spend money replacing them.

Or you can buy 0% depreciating policy as additional coverage. Many insurance companies now a days do offer them. Many though restrict it to first 3 years!

[dre@ms]

When my Dad was reversing the car from a slight slope, few inches ahead is the road platform. Once he released the brake, it went and banged on the platform, the bumper was bended like anything, i thought that the end of it, but when I reversed, it came back like a spring. Just a line of paint gone, but no problems with the bumper, it was there, still, like nothing happened.

I believe, the bumpers are hard enough and an impact makes it bend and once released, back to normal.

Due to this, if some crashes on the bumper, it doesnt have a dent, but in old cars, where the bumpers are metal, it would surely caused a dent.

Only thing we are worried here is the paint gone and not the bumper itself.

Just my 2C.

[Aroy]

Plastic bumpers are cheap. It is the body colour paint that kills. I was once at MASS and witnessed a customer inquiring about his bumper. The service adviser quoted 2500 for the bumper and 3500 for painting it. I on my part have replaced my Esteem bumper three times and refrained from painting it. Each time I paid less than 1500.

Another good thing about a black plastic bumper is that in case of small cracks, they can be easily repaired by heating the affected portion and heat bonding it. On my Ambassador, you had to first get the dent out, and then send it for Chrome Plating, a big expense thirty years ago.

[DicKy]

Originally Posted by Aroy

Plastic bumpers are cheap. It is the body colour paint that kills...............................Another good thing about a black plastic bumper is that in case of small cracks, they can be easily repaired by heating the affected portion and heat bonding it.

But the problem is today except few,most of the cars do not have black/grey bumpers even in the lowest version, especially white coloured bumpers just aggregate the scratches and dents.

[IMP]

The performance of car bumpers varies from manufacturer to manufacturer. The OHC had three piece bumpers at the front and back to reduce replacement costs. The Optra also has comparatively strong bumpers. Such designs in the end save money.

It would be nice to have a general list of cars in the Indian market that are less expensive to fix in case of a minor fender bender, a common occurrence on our roads.

http://www.team-bhp.com/forum/test-d...tra-1-6-a.html

Bumpers Found Lacking - The Early Show - CBS News

[siedo]

on a lighter note .

larger bumper also give more scope for manufacturers to introdue refreshed versions ofthe same car.

[Maverick1977]

What I have further observed that each manufacturer tends to make bumpers of varying strengths. Last year a swift rammed into me quite hard (apparently he didnt see me stopping in heavy traffic, LOL) from the back. My bumper did get a lot of deep scratches, but the condition of the swift bumper was pathetic, the whole thing had simply come off & had even got cracked. The swift owener was also quite surprise to the extent of damage to both the cars. Has this been the experience of others also. I remember some one on TBHP saying that his swift hit a dog lightly & not only did his bumper get damaged but so did his AC condenser.

[RaguHolla]

Originally Posted by Maverick1977

What I have further observed that each manufacturer tends to make bumpers of varying strengths. Last year a swift rammed into me quite hard (apparently he didnt see me stopping in heavy traffic, LOL) from the back. My bumper did get a lot of deep scratches, but the condition of the swift bumper was pathetic, the whole thing had simply come off & had even got cracked.

As far as I have observed is this is the case with almost all cars. Front bumpers are designed for pedestrian safety. They will be more fragile than back bumpers. Small touch from front will look worse than dud from back! As far as I know this is nothing new to Swift itself, its same with Fiesta (Just a touch to pole caused entire front bumper broken! :( ) also.

[designersf]

Originally Posted by siedo

on a lighter note .

larger bumper also give more scope for manufacturers to introdue refreshed versions ofthe same car.

Actually, in reality, you are right. It makes it easy to alter the bumper to any extent possible and launch a refresh.