songxu

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Hello Dan:

I am the first time owner of a SLK 350, 6 speed manual, 2005, bought used from local dealer, I love it.. The car has 16000 miles on the clock. It still has the original Bridge Stone Potenza Re050 Run Flat. The front tires has these wear patterns as seen in the pictures, but still have lots of tread left. The rears are very thin, but no un-even wear patterns, and probably good for several more thousand miles before the wear marks start to show. On some very flat road with rough texture, there is some kind of friction noise from the tires, like "wo wo wo ". I can also feel some vibration when drive over 70mph. So, I have the following questions:

1. what are these wear pattern tells you? Do I need new alignment? Or does it indicate worn suspension parts?
2. I read from a webpage states that MB-SLK's alignment is a $500 process and replace the shocks will cost $6000?! Sounds too high to me. What is your take?
3. Should I change the front and rear tire together? or the front tire can stay on. I really hate to wast if something can be used still.
4. I recently drove some road with pot holes and rough patches in Detroit area, every time the tire hit a hole or a patch, I not only feel the "bump", the car also feel un-settled laterally. No excessive noise though other than the "bump". Is that normal? I just recently have the car serviced by local MB dealer, and they did not mention anything wrong. Is that because the stiff run flat tire? Please advice.
5. Please also tell me the difference in ride between a run-flat and normal tire? Do the run-flat tires give extra harshness in ride when drive on patched roads? Should I switch to normal tire for a change?


Thanks in advance



Song

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DansSlk

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Hi mate, Welcome to the site.

Lets go from the top -

1) You can see its starting to scrub up the inners there but that in itself is not bad the car has some negative camber from the start and its kinda hard to tell from the pic but you say it has plenty of tread left so i would not be too concerned about the front at the moment but see answer 4.

2) The alignment should only cost you a few hundred dollars maximum some places don't even charge a hundred but always have a dealership do the alignment MB use a points system for the settings and not many other places have the info to do it right.

3) You should never change just one side of the car i.e change the left and leave the right on but changing the fronts and leaving the backs is not so bad but not the best option really and if it where me i would do them all at the same time.

4) Potholes and such like are very bad for the car indeed and most strikes will put your alignment out now when most people think of the tracking being messed up they think of the car squirming all over the place but its not like that you will very rarely notice anything weird until your tires are ruined, the squirm you where feeling could just be the result of the suspension action but could also be a symptom of a bad alignment so it might be worth getting it checked.

5) Run-flats are slightly harder than the ordinary tire and they tend not to perform quite so well under stress i would use non run-flats but its your choice at the end of the day.

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nmslk

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Is there any issue with mixing run flat and non run flat tires on a car? ie rf on front nrf on rear?

DansSlk

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No not really so long as the dimensions meet factory spec

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songxu

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I took a look of the front rims from in front of the car, obviously there is some negative camber on both front wheels. My question, if the negative is in specification, which cause these wear from insides of the front tires, then as long as the car is not behavioring funny, this kind of wear is nothing abnormal and I do not have to re-align (both sides seem to have very same amount of wear), right? As for tire, can I re-mount the tire to point the inside to outside, to save the tire for another 10000 miles? Doe this make the friction kind of noise go away? Is that too much a trouble and not enough benefit?

DansSlk

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From what i could see in the pics i would not call that wear abnormal and believe the car to be within spec when the pics where taken.

If they are both wearing at the same rate then thats a good sign.

For the tire no you cant re-mount it it must be installed in its direction of rotation and its "outside" correctly oriented

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