Replacing tire(s) on ML320

I had a flat tire on the front passenger side tire on my ML320. My wife didn't know about it and started driving, not realizing the tire was flat, and a few minutes later came back and told me about it. I'm not sure how
far she drove on a flat tire (never a good thing to do). Anyway, I temporarily put the spare donut tire on the car and took the wheel/tire to Sears.
I told them to just fix the flat. They said they couldn't because the tire was damaged from driving while the tire was flat. Ok, then I said replace the tire with a new one. He said that's fine but they could/will not mount it for me because the car is 4WD and the tread depth on the one new tire would be som much more/taller than the remaining 3 that it could damage the gear box. They are not authorized to put just one new tire on a 4WD vehicle. I then said, ok give me two new tires then and put them both on the same axle. Again they said no as they could not - for the same reason about the gear box stuff.
So I eventually caved in (perhaps I should not have) and purchased 4 new tires for the car. I did not want to do that as about 18 months earlier I had already purchased 2 new tures for the rear. So $600 later, instead of $125 later I have 4 new tires....
Does this sound right? Did I waste my money buy having to put 4 new tires on the car to have the same tiure tread depth to not damage the gear box? I'm thinking of calling Sears and discussing and maybe complaining to them. What is the deal on a 4WD car and tires with different tread depths?
Thanks, Walter
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She came back and told you about it? Why didn't she just change the tire?
Geoff
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Walter,
Considering an under-inflated tire would cause the same asymmetry, I have a hard time believing that this would cause a problem. I would suspect that Mercedes would take such an eventuality into consideration.
I have to believe therefore, that it is a salesman's lie to sell you a new set of tires.
That said, at least you have new tires on the car and I am sure it drives much nicer than it did :)
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I've had 3 SUV's in the past 15 years and nobody told me this and it wasn't in any manual. Did they offer to sell you a muffler belt too?
I'd call Sears about this and ask to see this "policy" in writing.
In my opinion it's sheer and utter bullshit. It's not like a tire with no tread is going to behave significantly different than a tire with full tread - even less of a difference exists between tires with half tread and full tread.
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Hi, it has to do with rolling diameter, less tread means that the diameter is less, makes it run slightly faster then the other side wich makes the differential work all the time instead of just when turning. Imagin having a low profile tyre on one side and a big tyre on the other. If the vehicle is full time 4WD it is not a good idea to have 2 new tyres on one axle and worn tyres on the other, similar problem to first example, but possably a little worse. I can't comment on this particular instance as I can't see the tyres, but their point is valid in general. Regards Roger
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Roger wrote:

Doesn't a differential work all the time anyway even when you're going in a straight line?
Ximinez
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The Spanish Inquisition wrote:

all things being equal and nearly perfect , no, everything should be going at the same speed when going in a straight line. But its a bit nit pickey as Im pretty sure there would be some movement, not as much as when your tyre diameters are out ( which will ruin a LSD centre quite quickly) Roger
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On Sun, 1 Oct 2006 14:39:38 -0400, "Walter Cohen"

As you were mobile, why did you not get a second opinion? I don't know the law either....
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Well, unfortunately I didn't. Long story short - I went back to Sears and spoke to the Customer Care Manager who said that if I can show him that there are no MB restrictions on replacing tires because of the 4WD and gear box stuff then he owes me some money. I told him I wanted to go with two new tires on the front axle but was denied by the original technician. He said I'd need to bring in the ML's owners manual and show that there are no restrictions. I just went through the manual and it doesn't have anything other than the comment that the front tires should be replaced in pairs (which is my case). There is nothing about the same tread depth or potential for damage to the gear box.
I need to call my MB dealer tomorrow and check with them about what the recommend when replacing a tire. Is there any MB online stuff anywhere which might have reference to anything to do with replacing tires on their cars?
Thanks, Walter
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