handling...

[Grey Ghost]

we all know the 123 chassis cars are HEAVY, especially with the diesel powerplant. the added coachwork of the TDs increases the wagon's weight even more (not to mention my two labs, who add another 160 lbs to the rear end)

what can be done to improve handling of these cars? my 300 TD's front tires screech around corners at speeds my '95 Tahoe handles easily

[Jordan_3202000]

Well there are a few options to improve handling on any car. You can try using high-performance tires. The grippier rubber compounds should reduce tire squeel and increse cournering grip. For my car i use Yokahama AVS Db S2 ultra high performance all season tires. Since i started using these tires, i can feel a huge improvment over a standard all-season tire. However this is not without a trade-offs as they typiclly last less than 20,000 miles. If you want to try something more drastic, you can install stiffer shocks and/or springs, that will help a lot. Also if the shocks on your car are worn, that will degrade handling as well. The rear shocks on my 300E wore out at 130,000 miles, i've heard thats typiclly how long MB shocks last. Do you still have the orignal shocks on your car?

[Grey Ghost]

the rear shocks have yet to be replaced. front shocks were replaced at 120,000 mi. the Mich MXV4s have 35,000 miles on them. the car was in the garage three weeks ago for 145,000 mi service and the tech didn't mention shocks or springs (I didn't complain about handling, either).

I don't expect it to corner like a new S-class car, but I'd like it to handle more competently than it does now

(I also have mounted Pirelli snow tires which I've yet to drive on)

[Jordan_3202000]

I think that your best bet for improving handling would be to go with a high-performance tire. Checking www.tirerack.com they have quite a selection of performance tires for your car. New tires and/or stiffer shocks are the only things i can think of that would improve handling for your car

[Grey Ghost]

if you want to get an accurate assessment of your tire pressures, use a GOOD tire gauge! The pencil-style gauges are NG. With a good gauge, on cold tires, I found out that my fronts were both 5 lbs UNDER!

others have recommended a visit to www.getagauge.com, but I hate to pay $6 to ship a $12 item

[Lyonstexas]

Most motorcycle shops carry a much better grade of air guage than the pencil type. If you have a dealer or independent shop that deals with the road racer crowd, they will have the best guages and no shipping involved. Road racers are pressure fanatics due to the drastic handling changes with the slightest psi change.

Tim

[D.L. SWINFORD]

G.G. Skip;
I bought my Digital Tire Gauge at Walmart fo about $9.00.
I'm not sure of it's accuracy but they claim +/- 1%.
It's not so much the accuracy as it is the consistancy.
Using the same gauge under the same conditions; that's where you obtain pressure control.
Happy Trails Beep Beep from the Spiderman on the Gulf Coast, Don,:p :p :p

[Marshall Welch]

I need to get new tires- the present tires have plenty of tread, but are old. My 300D-T (only 66K miles) presently has Michelin MXV4G tires- 195/70HR14's which I believe is the stock tire size. I think these are touring tires. I've been getting mixed advice about tires for this car. It has what seem to be common if not typical handling characteristics for these cars. It kind of floats along like a boat, nose dives a little when braking sharply, kind of soft shocks, steering a little loosey-goosey, and so on- exactly what we're talking about in this thread. I'm going to follow the advise above and get all of the suspension and steering components gone over, but what about tires?

I talked to a rep at Tire Rack who seems to be trusted by many, and he asked what kind of driving do I do, and I replied mostly freeway. He recommended touring tires- thought they would give a nice smooth ride and would be quieter than high-performance or performance all-season tires. But after that conversation I thought about it more and realized that I would LIKE to do more driving on windy roads and make tighter turns, and would like a slightly stiffer, tighter ride, but maybe subconsciously I just don't feel comfortable driving the car aggressively when the suspension/handling feels like it does. Some have told me that the all-season performance tires aren't as smooth of a ride and are noisier than the touring tires, wear out fast, etc. I realize these W123 diesels ain't no tight handling rocket sled like a BMW M3, but they ARE German cars, and not some Detroit luxo-barge either.

I'm also about to replace all four door seals and think that should help with the noise as well. Would appreciate hearing member's experiences with various tires in their W123's, especially diesels.

[pch2021]

the shocks.


these cars just don't handle right without the original bilsteins. i have a customer whose wagon was doing the same thing, and, acutally, maybe alittle bit worse, but adding bilsteins to his car made it handle soo much better.

also, chekc your upper control arms and springs. sometimes springs don't show a weakness until they are going aorund a corner at 30 mph.

[Alex]

Assuming there aren't any malfunctioning suspension components, I'm convinced that the solution is in the tires.

I've had different kinds during Big Blue's 222,000 miles, with varying results, though the car always handled well. With the noisy and rather hard P205/70/R14 Good Year Aquatred rain tires on the car now, the car still handles well but the ideal solution remains elusive. I'm just grateful there are no rattles.

If memory serves, the best ride came with the original Michelin tires. They didn't last long. The second pair developed imbalance problems. That's when I began experimenting with different tires.

[blkchambers]

Those tall 70 series tires will never handle very well. I have changed to 16" tires (P205/55R16) on 7.5" wide rims. They have the same O.D. as the stock size, so speedo is unaffected. There is no mod required in the rear, but there is a clearance problem with the tie rods in front. Slight mod required here, but I've had these on for about 8 years with no ill affects, and handling is MUCH improved with the lower profile & wider tires. Still have stock Bilsteins.
If there is interest, I'll be glad to lay out the modification.
Bob

[blkchambers]

The modification is simply to move the outer tie rod in so it does not rub the inner rim of the wheel.
1. Go to a parts car, and remove both steering knuckles. They are bolted to the hub assemblies with two 19MM hex head bolts each, and attach the hub assy to the tie rod ends.
2. Take the knuckles to a machine shop, cut off the angled ends, and have the bolt ends milled flat. This will give you a spacer that is about 17MM thick.
3- Get four new hardened bolts, 5/8" longer (the thickness of the new spacers) than the originals, and put the spacers between the hub and steering knuckle on the car.
4- Screw in the tie rods 5/8" to shorten them. You do not have to cut them to do this. There is plenty of adjustment.
5- You may have to limit the travel of the steering a tad via adjustment bolt, to keep the tires from rubbing the inner fender wells during full turn. Minimal loss of turning radius.
6- Get an alignment.
7- Install the fat tires, ogle your new look, and savor the better handling!

By the way, I installed 8" wheels originally. and they were too wide for the tires. I now have 16X7.5 (ET35), and it looks perfect. Use the P205/55/R16 and the diameter will be the same, and you'll have no speedometer or fender clearance issues. As I've said, it's been on my car over 8 years, and I've had no ill affects.

NOW FOR THE DISCLAIMER!! You are messing with the suspension; potentially life altering parts of your German engineered car. Do so at your own risk! I did and was very happy with the results, but if I screwed something up, there is no one to blame but myself!

I want to insert a photo, but don't really know how. I keep getting a message that says the pic is too large. (1.39MB) Any help on this?

[Grey Ghost]

all my handling "problems" subsided once I inflated the tires properly (34/38), serviced the self-leveling rear suspension and replaced the front shocks (I've also replaced: steering damper, outer tie rod assys, lower ball joints, and lower control arm bushings)

[Alex]

I admire what Bob has done with his car. Bet it looks great, too. After reading all that work that was done, all of a sudden my car handles terrific as is.

[blkchambers]

Wasn't that hard. I'll put in a picture or two if someone will tell me how. Now THAT is hard!!!

[Marshall Welch]

This is a follow-up to my earlier post in this thread. I took the car to my shop. They road tested it and checked out steering/suspension. Said it needed new idler arm bushings and the steering box needed to be tightened. I asked if it needed new shocks or springs, they said no- they could try to sell me a bunch of stuff, but that's not the kind of shop they are. I decided to follow their advise and see how the car handled afterwards. What a concept.

It also needed new tires- I already knew that. Got new tires- that helped a lot- went with all-season performance tires. Got the stock 195/70-14 size, Bridgestone Potenza 930i tires. I've read mixed reviews on these tires- some say they become noisy after 15,000 miles or so. But the original bundt cake wheel size doesn't give one a whole lot of good tire choices. I figured that I'll probably get some larger wheels when I'm due for the next set of new tires.

What a difference the new tires make- firmer handling than the touring tires that were on it- the kind of handling I like. The old tires were 8 years old- really too old- but the car hadn't been driven much on them, so I let them go longer than I should have. I've been reading that tires should be replaced every 4-5 years. Interestingly, the original spare tire was still in the trunk- a never used Pirelli P-3- S-rated. Got it replaced, too- would have been afraid to drive on it.

Got the idler arm repair done- that helped a lot, too. But forgot to remind them to adjust the steering box, so I'll get that done shortly. I'm getting an alignment first thing next week.