View Poll Results: What's the status of your Mirage's rear axle?

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  • Rear axle replaced under warranty; new axle within specs

    8 19.05%
  • Rear axle replaced under warranty; alignment is still off

    4 9.52%
  • Waiting for warranty replacement axle

    9 21.43%
  • Axle temporarily or permanently aligned with DIY fix

    4 9.52%
  • Rear alignment inspected & deemed within specs by dealer

    19 45.24%
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Thread: Rear Wheel Misaligned? (UPDATE: some rear axles out of spec; warranty replacement)

  1. #481
    Senior Member GrnBn's Avatar
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    These are the final values after the rear beam was replaced. If anyone wants other values listed, I can give them as well(SAI, included angle, caster, etc.)

    Front Left:
    0.0 camber
    0.03 toe

    Front Right:

    -0.5 camber (I think this helps fight the road crown)
    -0.03 toe

    Front:
    cross-camber: 0.5
    total toe: 0.0

    Rear Left:
    -1.2 camber
    0.07 toe (so close to 0!)

    Rear Right:

    -1.5 camber
    0.25 toe (this was/is the problem child, initially at almost a full degree beyond OEM spec IIRC)

    Rear:

    cross camber: 0.3
    total toe: 0.33 (more than I want, but WAYYY better than it was)

    Final Thoughts:
    The rear is non-adjustable, so it doesn't really matter what I think of those values. They're way better than they were, and only time will tell if these new values are "good enough". The front is pretty great, though a theoretical perfect would be 0.0 for all values and I'd just have to fight the road crown by hand.



  2. #482
    Senior Member Clessy's Avatar
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    From sitting and watching this alignment being done. This car is a nightmare to align. Took about 4 hours and tons and tons of adjustments.

    I can almost always promise you just by design you're gonna be a little out of camber every time you come in for service. Not to the point it was but the cars just so finicky that a few bumps will put you a little out of spec. Mines a smidge out of camber but no tire wear is noticeable at all.

  3. #483
    Senior Member GrnBn's Avatar
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    @Clessy: The toe is what's problematic to me, moreso than the camber. Camber that isn't super excessive(-5 degrees or so) won't hurt our tires nearly as bad as the toe being way out. When the toe is off substantially your basically just dragging that wheel along its side, whereas negative camber just means your contact patch is diminished.

  4. #484
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    Quote Originally Posted by GrnBn View Post
    @Clessy: The toe is what's problematic to me, moreso than the camber. Camber that isn't super excessive(-5 degrees or so) won't hurt our tires nearly as bad as the toe being way out. When the toe is off substantially your basically just dragging that wheel along its side, whereas negative camber just means your contact patch is diminished.
    Camber is spot on too. Unless you live int the country where it is a custom to drive on left side, you need .3-.5deg more camber on right to compensate for road crown. Otherwise car would be creeping off the road and you would need to turn in counterclockwise to compensate.

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        click to view fuel log View my fuel log 2015 Mirage DE 1.2 manual: 46.4 mpg (US) ... 19.7 km/L ... 5.1 L/100 km ... 55.7 mpg (Imp)


  5. #485
    Senior Member 3dplane's Avatar
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    Quote Originally Posted by mpaton View Post
    Is anyone who's done the adjustment with a chain or cable pulling the stub axles closer together able to measure the amount of tension they had to apply to get the correct toe? This could be done with a spring or fish scale; although you might need one for a biggish fish.
    In my case it would have to be a really big fish scale. My rear toe is pointing in .4 degrees on each side. The rig I made consist of an actual rear adjustable control arm from what ever car it came from,ending in round bushings like a "dog bone" at each end.

    To connect this to the most rearward part of the mirage rear axle I had to make 2 U bolts out of 3/8" threaded rod to pass through the slot directly ahead of the lower shock mounting points. Then use a combination of flat plates with holes and bolts to connect to the ends of the adjustable rod.

    The force required to hold mine near zero toe was enough to snap one of the 3/8 U bolt during a left turn one day!

    Now I have to admit that the bolt snapped at the upper right point during a left turn so the lateral twisting of the axle is what exceeded the tensile strenght of a 3/8" rod and not the force by itself that is required to hold it there,but still! We are not talking a few hundred pounds here! Also even though it looks like it cleanly snapped in half,it happened at the contact point where the U part turns straight leaving the axle.

    I re-did it using flat iron stock for the U part to wrap around the axle and left enough lenght for a few inches of weld to attach it to straight threaded rod to make my connections.

    Then after this repair when I got it up on the alignment rack to readjust the rear toe I was pretty pissed off about the whole having to deal with this crap thing and I wanted to pretty much just buckle this screwed up rear end in an effort to bend it permanently. I had a large adjustable wrench to turn the adjusting center nut and I saw both side toe go well outside of specs (both pointing out) but soon my whole rig started twisting as I'm pulling the wrench with all I've got.(maybe the two rods met inside the long nut?)
    Upon releasing the tension it springs right back where it naturally wants to sit so I just cranked it back to where the toe is zero.

    Also to clear my rig during rear suspension compression,I had to move the evap canister back about almost an inch.

    So in my case to compensate for a total of 0.81 degrees of toe I bet I have several hundred pounds (if not more) of pull force between the points just ahead of the rear shock mount bolts.

        __________________________________________

        click to view fuel log View my fuel log 2014 Mirage DE 1.2 manual: 66.3 mpg (US) ... 28.2 km/L ... 3.5 L/100 km ... 79.7 mpg (Imp)


  6. The Following 2 Users Say Thank You to 3dplane For This Useful Post:

    GrnBn (10-16-2015),mpaton (10-16-2015)

  7. #486
    Senior Member laceygirl's Avatar
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    I'm actually quite scared to have a wheel alignment done now

        __________________________________________

        click to view fuel log View my fuel log 2014 Mirage LS 1.2 manual: 38.0 mpg (US) ... 16.2 km/L ... 6.2 L/100 km ... 45.7 mpg (Imp)


  8. #487
    Moderator Eggman's Avatar
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    Quote Originally Posted by 3dplane View Post
    Now I have to admit that the bolt snapped at the upper right point during a left turn so the lateral twisting of the axle is what exceeded the tensile strenght of a 3/8" rod and not the force by itself that is required to hold it there,but still! We are not talking a few hundred pounds here!
    Bending the threaded rod stresses it, enough so that it will be more easily parted. Also, most threaded rod is made of mild steel, and thus is softer and more easily formed. What grade material did you use? I wonder if it failed at your bend? I'm going to guess that the forces were concentrated at that point of weakness, so no surprise to me that it failed.

    Quote Originally Posted by 3dplane View Post
    (maybe the two rods met inside the long nut?)
    This can be measured.

    Quote Originally Posted by 3dplane View Post
    Also to clear my rig during rear suspension compression,I had to move the evap canister back about almost an inch.
    Pictures of the whole project would be very much appreciated, if possible.

    Thanks for sharing this!
    Last edited by Eggman; 10-16-2015 at 10:24 AM.

        __________________________________________

        click to view fuel log View my fuel log 2015 Mirage ES 1.2 manual: 49.6 mpg (US) ... 21.1 km/L ... 4.7 L/100 km ... 59.5 mpg (Imp)


  9. #488
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    First 3dplane, thank you very much for this detailed yet concise and interesting answer to my question.

    The reason I asked the question was because I wanted to evaluate whether there it could be practical to push the trailing arms apart at the front, instead of pulling them together at the rear. From an estimate of the tensile force on your rig, I can estimate how much compression force I might need at the front.

    The biggest design issue I have with your rig is indeed what happens when the car leans or rolls during turns. In this case, as you know, the wheels effectively move further apart, and so the force on your cable is increased considerably. It will certainly increase the roll stiffness. i think the first car to use this setup may have been the MK I Golf, back in the late 70s or so. They were well known for cornering with the inside rear wheel in the air, and I suspect our cars will do that also, even without your mod. And of course we have electronic stability systems, so it's unlikely to get out of hand.

    A compression force at the front could alter toe without increasing roll stiffness, but would require some kind of secure hinge or ball joint to stop the compression force from "escaping".

    Given the way these twist beam axles deform, I am frankly quite surprised that the alignment specs don't include a requirement for a particular ride height before toe and camber is measured. If I had access to Alldata, i think I'd be looking to see if this was the case on other twist beam cars.

    Thanks again for a most helpful response.

    Michael

        __________________________________________

        click to view fuel log View my fuel log 2014 Mirage ES 1.2 manual: 46.0 mpg (US) ... 19.5 km/L ... 5.1 L/100 km ... 55.2 mpg (Imp)


  10. #489
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    @Mpaton, you are correct when suspension is subject to external forces, so any movement will rip tie apart. You could try to fit a stiff spring btw knuckle and ties, but IMHO the long term solution is to either replace axle or heat it up with torch and bend with sledgehammer or tie (or both).

    If it is just one wheel but overall cross-toe is within specs, you could try to adjust mounting points to correct trust angle.

        __________________________________________

        click to view fuel log View my fuel log 2015 Mirage DE 1.2 manual: 46.4 mpg (US) ... 19.7 km/L ... 5.1 L/100 km ... 55.7 mpg (Imp)


  11. #490
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    Quote Originally Posted by cyclopathic View Post
    @Mpaton, you are correct when suspension is subject to external forces, so any movement will rip tie apart. You could try to fit a stiff spring btw knuckle and ties, but IMHO the long term solution is to either replace axle or heat it up with torch and bend with sledgehammer or tie (or both).

    If it is just one wheel but overall cross-toe is within specs, you could try to adjust mounting points to correct trust angle.
    I'm not too worried about what you've called the thrust angle. I have heard that term used before, and in my mind it's a bit of a misnomer on FWD cars as there's little thrust coming from there. Unequal toe will certainly cause crabbing, but offset thrust a RWD car can be exciting!

    I'm hoping that the long term solution will be a new axle from Mitsubishi (and not a relaxing of the specs!). So I'm only thinking short term and I agree with you about long term solutions.

    I'm not so sure of your ideas on hammering or heating, because that cross beam is a spring, and springs are heat treated, and I am wary of ruining the heat treating.

    By my reading of this thread, GrnBn is the first to have an axle replaced by Mitsubishi with a positive result, ie giving acceptable toe. that could be luck, or it could be a breakhrough. It would be interesting to see if the part number that was fitted to his car was the same as the one for the cars up to now, but I don't think he's given us that information.

    The big problem with my compression device, at least in theory, is that just like 3dplane's tension device increases roll stiffness, mine would decrease it, at least for low angles of roll. And depending on how much force it needs to supply to correct the toe, if the required force was too high, it might want to stop the rear of the car from returning to level after a turn. That would be strange to drive , and hopelessly impractical.


        __________________________________________

        click to view fuel log View my fuel log 2014 Mirage ES 1.2 manual: 46.0 mpg (US) ... 19.5 km/L ... 5.1 L/100 km ... 55.2 mpg (Imp)


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