126, no wet traction...?

I've noticed that when my '88 420SEL looses traction in the wet (or dry for that matter) only the right wheel spins, the left one sticks to the pavement as far as I can tell. Should this car have any kind of positraction, or something to keep one wheel from just spinning, and spinning, and spinning?

I've actually had problems getting up hills because I can't get enough traction on wet asphalt. I've almost had an accident or two just from not being able to turn out into traffic fast enough.

I don't think this would be a problem if the previous owner hadn't put such cheap tires on the car (Coopers).
If this is normal for the car, would better tires make that much of a difference? I am going to replace the tires, regardless, in a month or so when I have enough $$ for new rims.

[ymsin]

I drive a 126 300SE and never had any problems on wet surfaces. I get a good grip feeling of the road. Perhaps, it is the tyres that make the difference. I use Michellin Energy MX 205-65-15.

Agreed. My guess is your tires. I've never had problems with the 560SEL and run the same tires as Kerry. Before I purchased those, my worn out Bridgestones did OK, even on the slick winter roads of Wisconsin.

I know the 560SEL had a limited slip diffy in '91, so I'm guessing your car does as well.

[Rich126]

All 560SEL's have limited slip differentials - All 420SEL's do not.

I've had Michelin MXV4s, Dunlop D6A2's, Pirelli P4000's, all are ok in wet weather, I have only spun out while going up steep hills at low speeds or when really flooring it.

Don't forget, you're driving a 4000 lb. 208" rear wheel drive car - not a Honda Civic. It's not supposed to do that well in the rain.

[420SEL]

To my knowledge limited slip was standard on the 560SEL, but not the 420SEL. Tires make a big difference. Cheap tires will ruin everything that makes these cars great.

hehe - doesn't matter what tires I put on my 560SEL I can often have difficulty with traction if I try hard enough :-)

[Oliverp]

I have great problems in the wet in the 300SE. The back end slides all over the place, even under slight gas.
I use Avon tires which arn't cheap, maybe they are just cr@*.
I have almost killed myself on many occasions in the wet, just pulling off from lights and junctions.
I don't drive hard in the wet, somethimes the back end just shifts out under the slightest tap of the gas pedal.

Strange!

[Q]

When I bought my 380SE, it had what appeared to be trailer tires on it. Jetzon was the brand. Anyway, they were hard as hell and would spin at the drop of a hat in the dry. Switched to Pirelli P4000 (not the greatest tire) and it will only spin when I push it really hard around a turn. Tire pressure could also be a factor. I believe my car calls for 29 rear and 31 front. I am probably wrong, but it is lower than what I am used to running tires at.

I've never had any traction prob on my 91 350SDL. Try some good tires, and I'll bet you will not either.

[420SEL]

If your back end is coming loose you could have a suspension problem. I never had that problem until recently I notice the ride getting worse, cornering not so great and I did have the back end come loose around a corner that should have been a piece of cake. Turns out I had a broken rear coil spring. 2 new one in the rear and the car drives good as new. Back end is glued to the road.

Thanks alot guys. I'm planning on putting Michelins on it once I get my new wheels. From what you guys are saying, I can't wait to get better tires.

I don't know THAT much about older Mercedes, but I'm learning as much as I can. It seems odd to me that MB didn't put a limited slip differential in a car as heavy as the 126(the non-560's anyway). Am I right, or is there a reason?

A W126 is a heavy car with a relatively narrow tire. This, in theory, makes a W126 more resistant to hydroplaning than a lighter vehicle equipped with a wider tire. I would wonder:

1. Are the current tires too old and hardened? You can forget about optimal traction in any condition under this circumstance, even if the tire is a premium brand.

2. Are your current rear tires worn excessively on the inside? I notice a fair number of 420's on the road with excessive negative camber of the rear wheels (bottom of tires stick out further than the top, as if you had 2,000 lbs. in the trunk). This was the hot setup on 1930's Auto Union Grand Prix racers, but has no place on the street. If this condition exists on your car, search this site for discussion of the problem/solution.

3. Oliverp discusses significant control problems in the wet with his 300SE. If I didn't know what make of car was involved, I would have assumed he was driving a late '60's Corvette with 400 hp and a limited slip differential. The behavior he is experiencing on a well balanced 4,000 lb. car with a six cylinder engine and open differential is very odd. I can't recall if the w126 has a rear subframe. If it does, I would investigate the possibility of worn components allowing the subframe to shift position under power or braking, causing the rear wheels to change direction and steer the vehicle.

[jsmith]

i've heard this very same complaint from brand new owners of lexus gs's. manufacturers hardly ever put first class tires on as a standard feature. i guess that's one of the first things you upgrade specially on a rear driver...

[TommyMB]

I use to have the same traction limited problem in the wet with my 500SEL (Euro). I solved the problem by replacing the lousy tires (XGT V). I have since used four different models of tires with no problems with traction at all.

By the way limited slip diff will do little if your tires do not have traction. Contrary to popular believes limited slip diff is a definite aid for high speed cornering because it limits the spinning of the inside wheel and allow the outside wheel to power through the corner, thereby maintaining a high cornering speed. With an open diff power goes to the spinning wheel and the car slows until the spinning wheel regain traction. That is why limited slip diff is a definit plus for track driving. For street driving with average skill drivers open diff is a safer setup because it promote understeer in the corners. Good luck.

[JimSmith]

I agree with the assessment that tires and suspension condition, including alignment are the most probable culprits. My 1991 350SD has its share of problems, but traction in snow and wet are nothing short of excellent. In fact, as stated by someone above, the benefits of a limited slip differential in such conditions is generally negligible.

Suspension alignment, when not in accordance with factory specifications, has the tires skidding slightly during the normal course of moving the car. Under these conditions if you add a little lubricant, like water, whatever the tire brand, the traction capability potential is seriously compromised. Ride with under the minimum pressure in the tire and you lower the threshold to losing traction even further, especially when the sidewall is rolled over and suddenly becomes the part of the tire with the highest normal force from the road.

I typically run my tires (Michelin Pilot XGT H4) significantly above the minimum tire pressures on the fuel filler flap just because I found the car understeered more than I liked with the pressures set according to the guide minimums. While there is a noted increase in harshness over rough surfaces, the steering response is better and the understeer, although still there, becomes less apparent during "normal aggressive" driving. Like I said though, I have never had this car unexpectedly transition from its understeering attitude to an uncontrolled oversteering condition in any weather and have driven it in all kinds.

Jim