Very Unstable C63 Coupe.

Discussion in 'AMG Lounge' started by J LAD, May 4, 2015.

  1. C36fan

    C36fan Hardcore MB Enthusiast

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    My car never felt unstable at 180+ maybe because my weight helps it to grip!;)
     
  2. C60three

    C60three Hardcore MB Enthusiast

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    Just out of interest.... It wasn't a blue 5dr Golf R (being driven like it was stolen) was it? Ours went missing Easter weekend :-(
     
  3. Simon_M

    Simon_M Hardcore MB Enthusiast

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    Your tyre pressures are wrong, read the manual and check the label on the door for correct tyre pressures.
     
  4. DSM10000

    DSM10000 MB Club Veteran

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    If the cap fits .................... :rolleyes:
     
  5. SLKGirl

    SLKGirl Hardcore MB Enthusiast

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    Couldn't agree more!
     
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  6. pstock

    pstock Hardcore MB Enthusiast

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    A couple of years back I had some rear tyres fitted at a main stream tyre fitting station (they were very KWIK at fitting) who shall remain nameless, Anyhow the car handled Sh1t at 70 mph the only thing that had changed was the tyres so took the car back to the garage and it turned out they had fitted 1 normal tyre and 1 run flat !! both the same manufacturer they changed the run flat for a normal apologised profusely and gave me a couple of quid back. Handling was much better after.

    Just a thought.
     
  7. renault12ts

    renault12ts MB Club Veteran

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    It does sound like that.

    I assume the rest of the suspension is in good order for relatively young car.
     
  8. grober

    grober MB Club Veteran

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    The suspension setting that effects stability more than anything is TOE. The C63 evidently comes from the factory with excessive rear toe to help stability. This leads to excessive tyre wear and many owners get it reset to the absolute minimum premissable to help this---- at the expense of rear end stability at high speed!!!!
    What's the real reason why C63 tires wear so fast? - MBWorld.org Forums

    I did a lot of research on this topic since I use my car as a daily driver and do about 25K miles per year. It was getting really annoying and expensive. The C63 comes with very extreme toe-in at the rear (spec is .48 degrees total toe-in at rear, compared to only .20 degrees at the front) which means you are essentially draging the rear tires down the road even when you are just cruising. Anything higher than .20 degrees total toe-in is considered unusually high. By the way, the camber spec is virtually the same front and rear at about -1.3 degrees. I do 90% highway miles and still only got about 4K miles out of the OEM pirellis. I switched to a 275 width tire with a much higher treadwear rating (Yokohama Avid Envigor in case anybody cares) and had the dealers alignment guy dial out as much toe-in as possible while remaining within MB safety specs (about .20 degrees total, just like the fronts). Now getting about 15K out of the rears with totally even wear from side to side and can't tell any difference in ride and handling. Sure there are a lot of factors that contribute to the horrible tire wear on this car (as discussed above) but I guaranty you the major one is the extreme toe-in setting from the factory.

    Maybe the previous owner got the car set up for minimum toe rather than the factory default setting????
     
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  9. V8andTurbos

    V8andTurbos Hardcore MB Enthusiast

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    My car can feel a bit unstable at higher speeds too. Cars been aligned and checked over and it's all good. Had it a 165+ and although it felt planted steering didn't give me too much confidence (needs 2 front tyres soon and balancing). Maybe just the nature of the car?

    On a side note, my car has a quaife diff fitted and is eurocharged mapped. Even in the dry with wot the traction kicks in, in Ths normal?
     
    Last edited: May 5, 2015
  10. ChrisA

    ChrisA Hardcore MB Enthusiast

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    In most cases with a Quaife diff and decent map fitted the yellow Triangle signifies plenty of smiles :thumb:

    In dry conditions if you set it up the right way you can have the triangle flickering away up to 130mph, nothing unusual there.
     
  11. Lee C63

    Lee C63 Hardcore MB Enthusiast

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    Very normal for the traction light to be flickering

    The light steering feel is a well known trait, usually solved with different springs being fitted
     
  12. OP
    OP
    J LAD

    J LAD Hardcore MB Enthusiast

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    Grober you may have hit the nail on the head here.
    Looking at the 4 wheel alignment sheet and it reads thus:
    Front Toe = 11deg near side - 9 deg offside.
    Rear Toe = 11 deg near side - 12 deg offside. Total Toe at rear = 23??????
    Camber front both 1.5 and 1.44 respectively .
    Camber rear 1.29 and 1.50 respectively.
    So the previous owner may have had the Toe altered as you say.
     
  13. grober

    grober MB Club Veteran

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    Might be worth having a word with a wheel specialist who is particularly versed in Mercedes wheel alignment issues- not casting aspersions here- but what's down on paper as OK and what experience dictates may be slightly different.
    Might be worth a call/PM to one of the specialists listed on the forum to ask their advice? e.g.
    http://www.mbclub.co.uk/forums/memb...-inmotion-geometry-alignment-calibration.html
     
  14. st13phil

    st13phil MB Club Veteran

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    If I'm reading your numbers right (and assuming that the Toe values are actually minutes and not degrees) then I make that Front Toe = 0.33 (vs 0.20 from grober's post), and Rear Toe - 0.38 (vs 0.48). This would mean that your car is running more than standard toe on the front, and less than standard on the rear.

    I echo grober's suggestion that a visit to someone who has a good reputation for understanding MB suspension geometry would be worthwhile.
     
  15. c32andy

    c32andy Hardcore MB Enthusiast

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    I felt the same problem when I first purchased my car and took it for a high speed run....so the conclusion make sure your tyres are all of the same brand and also more importantly the rear are the same make and have been replaced at the same time any uneven wear on the back really throw these cars, and finally try 40 41 psi after much tampering I found that these are the best pressures.
    TYRES are a big issue on a c63
     

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