How would well would a W123 or W126 survive a side impact? - Page 2 - PeachParts Mercedes-Benz Forum

lietuviai · #16 05-13-2004, 03:52 PM

Quote:

Originally posted by dmorrison
lietuviai

Please let me do a little educating here. Forgive me if you already have knowledge of this, but by your post I am not convinced.
As an airline pilot we deal with high speed aborts with and without ABS (without shown as an emergency training situation)
these are the philosophies on braking with and without ABS.

Without ABS. You apply brake pedal pressure untill you get about a 20% tire skid situation. How do you know what this is?? Go out and practice. Apply the maximum brake pedal pressure until the tires start to lockup and then YOU must be the ABS sytem and release the brake pedal pressure to ensure that tires do not lock up When they lock up they start to ride on melting rubber that is under the tire. This melting rubber is very slippery and causes the braking to deteriate. So go out and practice your panic stops in the NON ABS car.

With ABS. Remember to slam the brake pedal to the floor as hard as you can, then expect to feel pulsing in the pedal as the ABS does its job. Maintain the pedal pressure and steer away from the collision. Many people want to slam on the pedal and have the car stop. The most worthwhile benifit of ABS is the ability to steer and maintain control of the car while getting maximum braking. We practice this in our High Speed aborts in the aircraft. Apply maximum pedal pressure until you have competely stopped.

So
NON ABS -- brake and you regulate the skidding of the wheels. If skidding you will loose steering and possible control of the car. So don't allow the tires to lock up.

ABS-- Stomp on the brake pedal ( expect pulsing in the pedal) and STEER away from the accident.

Sorry if I am lecturing but Driver training in the US is terrible when it comes to ABS vs. NON ABS technique and proceedure. Since the majority of drivers are taught by there parents your getting old information when you are taught and there are a lot of new systems that have come out in the last 10 years or so.
When teaching my kids to drive, I taught them that there are some real idiots out there driving. If you don't believe that, then just watch "Jerry Springer" once. Those people drive cars and are teaching their kids how to drive.

Dave

Dave, I do have quite a bit of knowledge in regards to stopping and skidding which is why I didn't land in the drainage ditch with the 300D. I chose to omit going into too much detail about my driving skills only that I have over 25 years worth and have experienced a variety of panic stop situations in a variety of autos & trucks and have had no accidents that were my fault.
In my panic situation with the 300D I didn't have too much time to gather my thoughts other than lay on the brakes and steer the car appropriately. My adrenalin prevented me from being an effective ABS system. The tire rubber did melt an created four annoying flat spots on my tires which to this day have not worn off completely. I am reminded of them everytime I go near the 70 MPH mark.
I will take your advice on the non ABS braking and give it some more practice as I have many seldom traveled roads in my area. I use a different philosophy for braking which has become more instinctive in nature to me and your suggestion gives me a slightly different perspective to apply.

123 300D driver, there was an idea to standardize bumper heights in Europe not too long ago but unfortunately it became satirized in a number of articles which ended up making grotesque disfigurations of the popular models of autos. I don't know what has become of the idea. I haven't had a chance to measure the bumper height of my wife's Tahoe but my guess would put it to around 32". None of my catalogs mention that. Interestingly though, the Tahoe measures about the same length as a W126 300SD and only about 4" wider.

MT_Merc · #17 05-13-2004, 03:58 PM

I don't know if any of you remember this, but back when Ford came out with the Excursion, one of the features I remember was that it had a "blocker beam" under the front bumper that was designed to keep it from riding over smaller vehicles in the event of a collision. It's a good idea, and probably something that should be mandated (I'm not sure if any other carmakers have adopted anything like it).
I also remember, going a little farther back (probably early 90's), some automakers advertizing their new vehicles as having side impact protection. I didn't realize it at the time of course, but my thought now is "Wow, you mean like those heavy steel tubes in the doors of our Mercedes, which was built fifteen years ago?" If the seat belt holds you securely and the doors transmit the energy of the collision to the rest of the car rather than just the passanger compartment, you should be ok. I think Mercedes had these things in mind when they designed the 123's and 126's, long before the government mandated it. There aren't many new cars that I'd feel safer in than a 123 or 126.

lietuviai · #18 05-13-2004, 04:26 PM

On the subject of door beams but a little off topic, I used to have a '74 Mazda RX-4 coupe back in the late 70's early 80's and it had some huge steel tubes running through the insides of the doors. They didn't appear to be that strong because they got bent from merely opening the door a little too hard into a light pole. I know this won't compare to a M-B but I thought about sharing it with everyone.

rwthomas1 · #19 05-13-2004, 05:24 PM

Sorry, but I got a tough time believing a 6000+lb Tahoe outhandles and out brakes ANY MB other than maybe a Unimog. Unless the laws of physics have been repealed or your 123 is in real tough shape suspension wise it ain't gonna happen. Oh yeah, and what about a rollover? Since a Tahoe is a truck it doesn't have to comply with the car rollover standards. Driving around in a giant unsafe vehicle that makes you "feel" safe is ludicrous. Its called being part of the problem, not part of the solution. RT

WannaWagon · #20 05-13-2004, 07:15 PM

Another point from the Bradsher book is that many SUVs, in addition to being more PRONE to rollovers, also do not have roofs and roof beams that are as strong as cars. Again, this is because they are classified as trucks, and trucks do not have to meet the same rollover standards as cars.

So when your SUV rolls over because it doesn't handle as well as a car, it is much more likely to crush you inside because of the weak roof.

But I don't want to turn this into an SUV rant, because I think this is a valuable thread, and it's something that has concerned me also about purchasing a w123.

One of the things that worries me is the door beam itself. So OK, maybe the side of the car is plenty strong, but if you are hit in the side by anything, your head is going to whiplash into that hard metal doorbeam and possibly crack open in a fatal way. THAT is where a modern side impact or curtain air bag earns its keep, in my opinion. I've noticed that even on modern cars without air bags, these door beams are not very well padded. Why? And how likely is an injury of this sort? Wouldl it be stupid to glue some padding up there just in case?

Eric Eliel · #21 05-13-2004, 08:02 PM

I have a good buddy who is a safety engineer at Nissan in their SO CA headquarters.

Newer cars:
Air bags are "supplemental restraint" not primary restraint. Any collision over 40 mph, they are worthless. Collisions under 10mph and they create added $$ to repair. Between those two points, they are wonderful.

ABS: Significant safety increase and shorter stopping distance.

All the major manufacturers are designing in crumple zones like MB did years ago.

My last 300D: I ran into a flat bed diesel carrying Corian. I hit the right front wheel dead on. He drove off, my car was totaled including front frame damage immediately behind the "frame horns". I think the crumble zone helped. I did skid and I hit the truck at probably 15 to 18mph. Bruise on my shoulder.

Tow truck driver said based on the damage and skid marks most new cars air bag would have deployed.

I agree with DMorrison, I probably should go out and practice some preventative braking. Had I had ABS, I probably would not have had a total on my hands.

lietuviai · #22 05-13-2004, 10:27 PM

Quote:

Originally posted by rwthomas1
Sorry, but I got a tough time believing a 6000+lb Tahoe outhandles and out brakes ANY MB other than maybe a Unimog. Unless the laws of physics have been repealed or your 123 is in real tough shape suspension wise it ain't gonna happen. Oh yeah, and what about a rollover? Since a Tahoe is a truck it doesn't have to comply with the car rollover standards. Driving around in a giant unsafe vehicle that makes you "feel" safe is ludicrous. Its called being part of the problem, not part of the solution. RT

The Tahoe according to the owners manual requires a distance of 158' to stop from 60 MPH and the the 300D according to the owners manual requires 165' for the same stopping distance. I'm still looking for the handling specs for both vehicles. I refuse to believe that our Tahoe is an unsafe vehicle. Remember also our Tahoe has the police suspension package, it was previously owned by the US Bureau of Land Management, it is not just a generic Tahoe.
RT, I invite you to drive our Tahoe and the 300D to compare for yourself which is the better handling vehicle.

rwthomas1 · #23 05-13-2004, 10:59 PM

You can believe what you want. Safe is a relative term. Compared to a MB I think the Tahoe is unsafe. Compared to a Kia Rio its quite safe. I also don't buy what I read in owners manuals. Likely the MB is conservative and the Tahoe a best case senario. Kinda funny how a vehicles performance is usually either much better or worse once professionals do reall testing on them. Your tahoe, police spec or not has the same brakes as Suburbans. They have been under braked for years. Just look at any Sub owners group board adn you will find threads about brake upgrades, frozen rotors, Baer brake upgrades etc. Either way its a moot point. Drive what you want, its a free country. RT

WANT '71 280SEL · #24 05-13-2004, 11:07 PM

Does a w116 stop faster than a w123? I would think so. It's frightening how fast my car stops. Two weeks ago I had my car full of 3 other people and I locked the brakes up at 50 mph. Rear brakes locked also, something that seems just about impossible on American cars, but I've never stopped so fast in my life. It was like the seat belt was going to rip through my shoulder. I would assume the w126's are similar, but I think mine stops better than my mom's 420, and it has new pads, calipers, etc.
I've never driven a w123, I hope to some day to see what everyone raves about, but I hardly doubt they're as good as the w116 handling wise. Just my $.02.
Thanks
David

DslBnz · #25 05-13-2004, 11:45 PM

Guys, the owner's manual claims that all W126(up until 1989?), W123, W124, whatever, stop in exactly 165 feet. That is not true at all. The later W126 ('86 +) had stronger braking systems with massive front rotors and brakes. The later W124's did too.

The chart listed in the back of the manual is not meant to be accurate. It is just showing what would happen if you lost power to the brakes. Be it partial failure, or complete failure.

Maybe I'm crazy, but the post '86 S-Class vented rotors look like they're about 13 inches. They are really massive discs! Pretty heavy too.

BTW, thanks to the "wonderful" stopping power of the W126, I snapped the front swaybar off of mine like a twig while trying to avoid a FFC(Friendly Forest Creature).

As far as side collisions go. Um....Side bags and curtains are certainly nice. In the case of the W126, its solid enough to hold its own if a train collided with it(seriously). I'd just have to see it coming and brace for impact. Otherwise the B-Pillar's color would suddenly change from either parchment, palomino, or blue to a rather spotty garnett red.

:p

lietuviai · #26 05-14-2004, 10:44 AM

I'm glad to see we're back on the subject of side crashes. We got a little side tracked comparing apples with oranges for a while. The 300D that I have was the latest addition to my stable. I bought the 300D on the idea of something a little more economical than the rest of the vehicles that I own. I bought it last year in March when fuel prices rose considerably the last time. The only reason why I bought the 300D was that I was sick of Japanese cars and their difficult seviceability. I didn't know much about the W123's but I assumed that they were very reliable based on what I had heard in the past. I learned a lot about them since joining this forum and a couple of others. I had heard that they are quite safe crashwise and I wanted to hear more about their side impact survivability. I'm still interested in hearing more about it.

MT_Merc · #27 05-14-2004, 11:34 AM

Just a note on big vehicles and brakes, most truck-based vehicles (such as a Tahoe and the E-series vans we've had) have heavier duty brakes than cars. The only issue is that the brake bias is often your enemy when the vehicle is unloaded, it tends to be biased towards the rear more for better braking when loaded, which is why you find a lot of trucks with rear-only antilock. Our van stops quite well despite it's size and weight; you've gotta remember and take into account that you're driving a bigger, taller vehicle, that's all. As far as I can remember, we've never replaced a rotor or drum on any of the vans we've owned, by the way.

Getting back to side impact though, the fact remains that it's very hard to fully protect against. Lots of metal and crumple zones help with front impact, but you can't do that with side impact. That's partly why city driving can be more dangerous than highway driving, a side impact at 40mph is about as likely to cause a fatality as a front impact at 75. It all comes down to restraint and energy absorbance, and both are more of a problem with a side impact. There's not a whole lot you can do about it unless you wanted to build a NASCAR-inspired safety cell and seat system. Then again, you're taking a risk just getting out of bed in the morning.