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1981 Mercedes-Benz 300TD
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Discussion Starter #1 (Edited)
. **Don't let the length scare you**

The title is the short gist of my question, but if you have time, heres my thread I would prefer everyone read and share comments on. I REALLY like the quality feedback and I DO read it. :thumbsup:

I'm always one to push vehicles to the limit, specifically my 300TD. Yes, mostly for fun, I am 18 ya know,:p but also to test there limits, see what happens when its "out of control" which includes evasive driving maneuvers. Please understand, I do not abuse vehicles, I'm a stickler for maintenance and very often check mechanical items, but once thats done I drive them HAARRDDD..... from time to time. :D I'm also a calculated risk guy, not some teenager endangering your family on the road. Anyways, I think its sad how many people end up rear ending someone or having a single car accident while trying to avoid an accident simply because they don't know their vehicle and its limits. This is particularly concerning with our w123's that usually lack ABS, Traction Control, front airbags, or any airbags for that matter, and they are heavy. Quite dangerous compared to the modern vehicle. All we have is a mere seat belt, and maybe a properly adjusted head rest, to protect us at low and high speed and its only effective in one direction. In addition, many of you are in your w123 everyday, so we all should put an emphasis on this topic.



Story time! :D A month or two after getting my TD, I found a secluded strip and floored the brakes from about 35MPH. The thing turned into a screeching sled as the rear end stepped out of line and I plowed through the imaginary wall ahead. My moms 09 Highlander, a mid-size SUV, stops faster from 45 MPH than this at 35. :eek: That day I learned its probably better to swerve than to brake hard in the TD. Definitely something good to learn now, not the 50 milliseconds before impact (like a car or person) as many people do... I'd like to test out of that "Accelerated Crash Course." get it? ;)

I've done similar tests like low speed (~15mph) swerving on dry pavement and on wet, but what would happen at 70MPH? I don't want to leave my TD, its awesome! but I also don't want it to be my coffin. I like sharing info but I REFUSE to come limping back to you all with a thread titled "300TD and myself are totaled, turns out it WILL roll at 70mph....:crybaby2:"

....so I'm not testing this one but will ask, what do you think a w123 would do at 70mph on wet and dry pavement? AND What would you do if you had to suddenly avoid something large in your lane? How might the wagon handle differently from the sedan? (Include the described car model)

Conclusion:
I refuse to be the grandpa doing 50 in the slow lane but also don't want to ignore the real danger and rely on luck. Dangerous things happen on the road, but I pray that that Thing wont be my last.
 

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85 Audi Coupe Quattro, 85 Audi Coupe GT, 71 BMW turbo 2002, 73 BMW 2002tii, 85 BMW 635csi
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If you want to improve stability, you must lower the center of gravity. Any car will roll over if pushed beyond its capabilities.
 

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W-1-2-3 Go!
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There are a number of things you can do in order to brake better and have better vehicle control.

The stock brakes are good for their time, but compared to today's cars that have ABS, traction control and ventilated disc brakes, the W123 seems to be left behind. You can install ventilated discs from a 2nd gen W126 but you'll have to drop the stock 14" wheels and get at least 15" wheels to clear the calipers. The calipers also change to accommodate the wider discs. Pads are the same IIRC.

If the vehicle veered to one side at the rear end, the rear brakes may not be balanced.

The wagons have a slightly bigger rear brake to accommodate the heavier rear end/load. Consider too the condition of the tires and suspension.

Some members have autocrossed their W123 in stock form and have done amazingly well. These cars may be slow off the line but handling wise, they can turn faster than others can think. They have a bit of roll when turning, this is due to the suspension geometry. If I take the same turn on my commute route in my 190E, compared to the 300D, I can definitely go faster in the smaller car due to suspension and chassis differences. In both cars, my cheeks start hurting when I slam on the brakes hard on an empty stretch of road from 60+ mph. Both cars have good tires, good suspension and brake systems.

There was a video comparing MB technology where the W123 bit the dust, while the new technology helped assist drivers of modern cars to avoid an accident. These are 30-year-old cars and surely, the technology is older, since the cars were designed in the early 70's.
 

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'86 W123 200, OM617 non-turbo, bastard 5-speed; '95 W202 C250 Diesel, OM605 non-turbo, 5-spd man
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Very interesting, since I've found the Mercedes outbrake many cars, even without ABS (which neither Donkey has, nor my father's three 230E's had). The car which donated its engine to Donkey was written off (read: slightly damaged) because of worn shocks causing it to swerve under braking, something Donkey hasn't done even from more than 60 mph (in South Africa there's plenty of open road with speed limits legally set at 75 mph).

I find, however, that there's still no substitute for far-sighted driving. It gives you time to properly assess the driving environment and identify and manage potential accidents. My only hope is that, should such an accident happen to my, I die quickly.

Speaking of Dad's 230E's, one of them had SLS, and that really had stable braking - it hunkered down like a lion suddenly spotting prey.
 

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I'm not sure if my brakes or steering are much different from yours, but I have a 126 500sel without ABS and find the brakes to be insanely good, particularly for such a large heavy car. It stops quicker than my 2007 saturn and my former 1999 cavalier, which of course both have ABS. However, I will say that there is a learning curve in using non-abs brakes to their full potential. About high speed maneuvers, it's my understanding that since these cars were legitimately engineered for the autobahn, they made the steering just soft enough so that if you do make a high speed maneuver, you won't just go spinning out of control like you probably would with a stiff suspension, tight steering BMW,(before they had the steering technology to detect speed and correct thusly.) I think 123's are generally low enough to the ground that they would slide if pushed to do so, but under the right circumstances even the lowest cars can flip.
 

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'86 W123 200, OM617 non-turbo, bastard 5-speed; '95 W202 C250 Diesel, OM605 non-turbo, 5-spd man
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The W126 is considerably wider (better) and longer (better) than the W123. The problem with this generation of cars is that the mass was above the wheels, not between them.

I don't understand what you need by "soft" steering, though; the only "softness" is determined by the suspension.
 

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1977 300D 4sp basketcase
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My 300D feels so floaty at speeds over 45mph. I would never thing of driving it hard lol My $100 1986 Fiero SE I had a few years ago was rock solid at 112mph. Unfair comparison right lol
 

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This is just hearsay, and about the 126, but by soft steering I mean the wheels don't turn as far as another car might if you turned the wheel the same amount. Don't get me wrong it steers amazingly, particularly for the old boat that it is, but the steering wheel isn't quite as responsive as many cars. It's just the way the steering gearbox is set up I guess. Somehow it does still manage to have a very good turning radius though.
 

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'86 W123 200, OM617 non-turbo, bastard 5-speed; '95 W202 C250 Diesel, OM605 non-turbo, 5-spd man
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This is just hearsay, and about the 126, but by soft steering I mean the wheels don't turn as far as another car might if you turned the wheel the same amount. Don't get me wrong it steers amazingly, particularly for the old boat that it is, but the steering wheel isn't quite as responsive as many cars. It's just the way the steering gearbox is set up I guess. Somehow it does still manage to have a very good turning radius though.
So you're referring to how it feels like, after you turn the steering wheel, the car first leans into the opposite direction (however much or little) then actually changing direction? That would be the suspension.

There is a difference, albeit a relationship, between "roadholding", "handling" and "steering".

"Roadholding" is the interaction between the car and the driving surface. This depends on how well the car transfers its mass and forces onto the road i.e. suspension design (suspension inertia, sprung mass/unsprung mass ratio, suspension geometry etc, spring rates, damping rates etc.) driveline (FWD, RWD, AWD) rolling moment (vertical distance between CoG and suspension instantaneous rotation point) and such.

"Handling" is the interaction between the car and the driver. This depends on the same as the above. Therefore the two are almost mutually exclusive. A car that responds fast to the driver's input can do so because it has less inertia, which may mean less mass, which in turn will mean less traction. So the question for a sports car or supercar designer is "how little traction is just enough?"

"Steering" refers simply to the steering circle as a function of the steering wheel angle, or more accurately the wheel angle/steering wheel angle ratio.

These cars were designed with safety and comfort in mind, so they offer tremendous roadholding. Unfortunately their CoG is quite high above the ground, resulting in a large rolling moment that the soft suspension cannot quite counter. Their wheels fold quite a lot into the wheel well when steering which is why they have such small turning circles.

So, these cars combine sharp steering with excellent roadholding, at the expense of handling.

Sorry, sorry, geeked out again...
 

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1981 Mercedes-Benz 300TD
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Discussion Starter #14
You can install ventilated discs from a 2nd gen W126 but you'll have to drop the stock 14" wheels and get at least 15" wheels to clear the calipers. The calipers also change to accommodate the wider discs. Pads are the same IIRC.
Aside from avoiding boiling brake fluid, how else might the brake swap change my braking? With a larger diameter wheel, I'll have a slightly larger contact patch which should increase traction. Those are the only two gains I can think of at the moment. However, I have heard of people performing this swap. What do you all think?
 

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'86 W123 200, OM617 non-turbo, bastard 5-speed; '95 W202 C250 Diesel, OM605 non-turbo, 5-spd man
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I think that wider wheels rather than bigger diameter wheels will add traction.
 

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1981 Mercedes-Benz 300TD
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Discussion Starter #16
I would love to find some large wide wheels with nice rims. It doesn't really look like these vehicles have many flashy options.
 

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I get the impression that brake responsiveness can be much improved with the braided steel lines. haven't tried this (yet).
 

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I get the impression that brake responsiveness can be much improved with the braided steel lines. haven't tried this (yet).
The responsiveness of my brakes improved with new rubber brake hoses. I went against SS braided lines as recommended against in this forum. It also improved with a new master cylinder.

Check this out


Even in tuned form there is some roll, as demonstrated by this AMG 500CE



Regarding steering: the ratio is slower than most newer cars, and it doesn't help the wheel is so large. You turn a certain angle of the steering wheel and the car does not turn as much, compared to when you turn the same angle on the steering wheel, on a modern car. Plus, when you turn hard, the car rolls right away in stock form, whereas a newer car has stiffer stabilizer bars, minimizing roll and allowing the vehicle to turn with a more flat posture.

However, despite the body roll and slow response, these cars have immense "give" that it allows the vehicle to grip and handle in a very predictable manner.
 

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I will tell you the answer your question OP, I was in a 1983 300CD on a freeway 215 merging into 15 in SoCal. 2 lanes from 215 merge into 3 lanes of 15 for a total of 5 lanes for a while. I was in the right lane on 215 merging into 15 very close to the gore point. I tried to make a lane change to the left. I signaled, then looked around me, it all seemed fine to process further then I did so. In the middle of the lane change suddenly another car driving in the 3rd lane of I-15 approached the same lane as me almost shoulder to shoulder, I was slightly behind it so I was going to hit him in the passenger side fender. I was doing 65-70 and I suspect the other guy was around that speed too but felt like he came out of nowhere. So silly me, in the moment of emergency panic I would call it, yanked the steering wheel to the right to avoid collision and I did avoid it after all, A.K.A your evasive maneuver. Unfortunately, the car started skidding, fishtailing, call it however you want but this shit is crazy on the freeway where they were cars all around me. So I tried to gain control over the car trying to countersteer while my pedal was off the gas pedal, and on the 3rd skid left and right, I hit some another car on the passenger door with my tail, then suddenly my car started overturning and hit a guardrail just before a creek bridge near by. 50ft of the guardrail was gone and my car rested on its wheels facing the opposite direction behind the guardrail 5-10 feet away from the creek. Lucky me, since a small kid I have that habit of putting the seat belt on immediately after I enter my car or any car. So I came out without a scratch! Nobody could believe it, the CHP officer and the other parties that stopped, even the idiot driver who basically cut me off. I don't want to say but the car was more than a total loss LOL. Dents on each panel, frame was badly twisted, front passenger side had the most damage. from the guardrail. Even the drivers side window was shattered in pieces and the windshield badly crumpled inside the chassis.
I think if I had ABS and/or traction control this sliding might have been easy to avoid but...it a hard life , and to top it off the other guy's insurance doesnt want to pay for my car since we did collide bla bla and essentially telling me to go to small claims court. fkin bullshit man. U guys invest in a dash cam (as I did with my other car) for these classics cuz u never know. Happy and safe motoring all yall!
 
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