| Author | Message | ||
     Ryan Roundy (Rrefxut) New Member Username: Rrefxut Post Number: 14 Registered: 12-2003 |
Hey Guys, I'm building my own front bumper, and noticed the stock bumper had crumple zones on the mounts just before it bolts to the frame. Is this something I need to consider in building mine? I was going to try and sell the stock bumper, but would I be safer taking the mounts off of it, and using them on my custom one, or am I just being paraniod? If I don't have any, are my air bags going to be more sensitive to set off? I remember smitty built had a problem with this on jeep wranglers when jeeps first started carrying air bags in the early 90's. Has anyone had any problems with this? Thanks for the info, you guys are great! | ||
| Ryan Roundy (Rrefxut) New Member Username: Rrefxut Post Number: 15 Registered: 12-2003 |
Forgot to add something, I figure it won't be a problem, after all, if I hit something hard enough to affect a crumple zone, then I've hit it hard enough to deploy the air bags anyways, so I'm planning on building it without them. Also, the new bumper will have a winch attatched, and I don't want the crumple zones to become stretch zones either, I just figured since it has them before I mess with it, I'de better ask to be on the safe side. Thanks again guys. Ryan | ||
| Donald McFarlane (Dsmcf) Member Username: Dsmcf Post Number: 55 Registered: 11-2003 |
I agree with your conclusion and for that matter your logic but not your premise. You presume that the airbag would activate at a similar or lesser impact force than that which would start to result in a plastic deformation of the crumple jobbies. Quantitatively, I can't really comment on the dynamics of this. However, qualitatively as an EMT who has seen a few bent vehicles, I am extremely confident in saying that you need a substantially higher impact to set off the airbag than you need to cause some moderate deformation of the crush cans (ooh err I remembered the correct term for them). Without a doubt the more rigid bumper will translate to a similar external incident producing higher impact forces and thus more readily triggering the airbags. But the criteria on which they *should* trigger is not an external one. It is about protecting the occupants -- who, without the benefit of said crush cans in spreading out force over time, are also being subjected to greater forces. Indeed, the airbag trigger mechanism is mounted in between the two front occupants, over the transmission tunnel, and uses a 2-factor trigger -- a metal weight attracted to a permanent magnet which will separate therefrom at a given (forward) deceleration; and an electronic decelerometer which must exceed some specified deceleration. Common sense would appear to suggest, then, that a substantial side impact is less likely to trigger than a substantial frontal impact. This is also true. Personally, I am very happy to have my airbag and pre-tensioners, although I am strongly considering getting rid of the passenger airbag, both because I need the space to mount stuff, and because when I get round to mounting my laptop it would do a good job of turning that into a guillotine and/or projectile. Returning to your original point, I would be far more worried about accidentally triggering the airbag electrically (e.g. by shorting a cable or static discharge or whatever while working on the vehicle) than by the odd bump or scrape suffered on the trail. The above is IMHO only. YMMV. I disclaim all common sense and intelligence and caution you to ignore my ramblings. | ||
| Peter Matusov (Pmatusov) Senior Member Username: Pmatusov Post Number: 1221 Registered: 09-2002 |
Ryan, there was a long-winded debate of this exact matter - about a year and a half ago. Check the archives for airbag- or non-airbag ARB bumpers. the outcome was - IIRC - that the airbag is likely to deploy at about 40mph frontal collision in a stock truck. Using a non-airbag bumper may reduce this speed to 25-30 mph (the tougher you build the bumper, the lesser will be the speed at which the SRS goes off). However, a 25mph frontal hit is pretty damn hard already. | ||
| Nadim Samara (Discodino) Member Username: Discodino Post Number: 188 Registered: 02-2003 |
Simply take out the fuse for the airbags when wheeling...that's what we do here in the desert in KSA. |
