About 2 months and 2,000 miles ago I bought a set of 4 Hankook Optimo H724 205/75R14 from a tire shop that was recommended by a local MB garage and got rave reviews on Yelp. They rolled me out of there with the psi at 42 on all four tires. I dropped it down to 34 when I got home because I could feel something wasn't right. The tires felt okay for the most part but the car was shaking at 68MPH, so I took it back to get re-balanced. They didn't get it right that time either. I took it back a second time and now the shake at 68 is almost gone but the ride in general sucks. On a freshly paved smooth highway it feels like there are little ridges here and there but it's not the consistent vibration you get from a grossly out of balance tire. It's frustrating because I can't pinpoint it at an exact speed, it's vaguely between 40 and 55 mph and there's a little vibration close to 70.

I'm tempted to go to another shop to give me an objective diagnosis after running it on there balancer, but don't want to waste $75 on something the original shop should take care of. Could a new tire start to delaminate so quickly? Is there something I can see or feel on the tire that will tell me what's going on? BTW, the car drove very smoothly with General Altimas, and I rebuilt the front end last year. I know it's not the car. Thanks,

Otto

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'81 300SD

Swap the tires front to rear to see if things change.

When's the last time you checked the front wheel bearings?

You did a bunch of front suspension work recently, right? Is there anything you might have missed? Be honest now, did you use any Uro parts?

Sixto
87 300D

I used a Karkan tie rod on the passenger side that I'm a little suspicious of because the boot started to split two months after I installed it. The thing is, this car felt great on the highway until I got these tires. That's a pretty strange coincidence if steering components are breaking down at the same time as the acquisition of these tires. Plus, sometimes the car shakes but the steering wheel doesn't which means that the faulty tire is probably in the back or even worse I've got a flex disc heading South.

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'81 300SD

Check the age of the tire, info should be on the sidewall. Sometimes shops might install older tires without the owner/customer noticing. I always try to get the newest when getting tires installed. 1-2 months old should be okay, but if it's close to a year, I'd request for newer. Age is determined in number of week manufactured in a certain year.

Tire Tech Information - Determining the Age of a Tire

Karlyn maybe? They seem to have a story behind them but they'll be unique if they haven't farmed manufacturing to China.

One measure of tire quality is consistency from batch to batch and among tires in a batch. It could be there's a dud in your set. Maybe moving the tires around will change the driving characteristics you perceive such that you can associate the change with moving the dud.

Sixto
87 300D

Yes, Karlyn is the brand and they are, or at least were made in the U.S. when I bought them. I felt really good about getting a U.S. manufactured product, but it really disappointed me. I replaced the driver's side tie rod with a Lemfoerder, and it's been fine.

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'81 300SD

I checked the flex discs and suspension, and everything looks and feels fine. After switching the passenger side tires front to back, the ride was the best it's been, not perfect, but better. After switching the driver's side tires, the ride was the worst it's been.
The shake at 68mph is barely noticeable, unfortunately the car shakes a lot at 75mph. The shake isn't in the steering wheel, you feel the whole car vibrate. I guess it's one more trip back to the tire shop. Any recommendation as to how I should approach the supervisor other than telling him about the results of my tire rotation? Thanks

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'81 300SD

How about a pic of your SD.

Just click on the avatar.

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'81 300SD

We are fortunate to be able to purchase Michelin Tires.
(Reputed to be the only truly ROUND "Skins" manufactured)
(There are Tires,which say Michelin on the sidewall,
all else are Tug-Boat Gun-whale Bumpers!)


Can you guess what I'm gonna suggest?

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'84 300SD sold
124.128

What kind of financing can you offer me to get a set of those Michelins?

The General Altimax were very nice highway tires but were starting to wear out fast after 25K. I was also looking for the 75 profile to make city driving a little more comfortable which it has. I've pulled tires out of a junkyard and had them balanced on a static balancer by a guy in a pick up truck and those were smoother than the POS' I'm driving now. I need that shop to replace one or more of these.

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'81 300SD

I used to think Michelins were the best tires to put on a Mercedes but then my shop got a Road Force balancer. It became obvious very quickly that even brand new Michelins are not the "roundest" tires. Continentals are consistently the best tire as far as sidewall springforce is concerned.

Given the brand of tire you have mounted, I'd suspect excessive "spring force" in the sidewalls causing vibration that a traditional tire balance won't solve. You need to find a shop that has the Road Force balancer to get to the root of the problem.

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90 300TE 4-M
Turbo 103, T3/T04E 50 trim
T04B cover .60 AR
Stage 3 turbine .63 AR
A2W I/C, 40 LB/HR
MS2E, 60-2 Direct Coil Control
3" Exh, AEM W/B O2
Underdrive Alt. and P/S Pulleys,
Vented Rear Discs, .034 Booster.
3.07 diffs 1st Gear Start

90 300CE 104.980
Milled & ported head, 10.3:1 compression
197° intake cam w/20° advancer
Tuned CIS ECU
4° ignition advance
PCS TCM2000, built 722.6
600W networked suction fan
Sportline sway bars
V8 rear subframe, Quaife ATB 3.06 diff

The Hunter website has a GSP9700 finder and it says that the shop I purchased the tires at has one. The machine I saw the kids balancing the tires on didn't look anything like it. Maybe the shop returned it, or it's out of service.

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'81 300SD

If the shop sells tires then they usually don't want a machine that tells them that their new tires are junk.....

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90 300TE 4-M
Turbo 103, T3/T04E 50 trim
T04B cover .60 AR
Stage 3 turbine .63 AR
A2W I/C, 40 LB/HR
MS2E, 60-2 Direct Coil Control
3" Exh, AEM W/B O2
Underdrive Alt. and P/S Pulleys,
Vented Rear Discs, .034 Booster.
3.07 diffs 1st Gear Start

90 300CE 104.980
Milled & ported head, 10.3:1 compression
197° intake cam w/20° advancer
Tuned CIS ECU
4° ignition advance
PCS TCM2000, built 722.6
600W networked suction fan
Sportline sway bars
V8 rear subframe, Quaife ATB 3.06 diff

Shops don't normally use the roadforce balancer unless you request it. I'm sure they just spin balanced your tires.

From your description it sounds as if the tires simply are not round and/or have road force variation. I am skeptical the shop can ever make them work. My $0.02 - go have them exchanged under warranty and try something else.