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Lowered my car this morning with adjustable links: Key steps that ensure precision

Discussion in 'Model S: Driving Dynamics' started by artsci, Mar 23, 2015.

  1. artsci

    artsci Sponsor

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    #1 artsci, Mar 23, 2015
    Last edited: Mar 23, 2015
    More planning went into my car lowering than I had anticipated but when the installation was done the car ended up at precisely the height I had targeted with no further adjustments necessary. I highly recommend adjustable links as they make precision far easier than other DIY methods and eliminate the guesswork and experimentation. The steps below are a foolproof method for lowering the car to your desired height without trial and error experimentation, which can be a major PIA.

    As there are several other threads on car lowering I'll dispense with other ground that's been covered before and cut right to the chase, which is to save some time and trouble for those who are planning to lower their cars.

    Here are the steps that I think are critical:

    1.Measure the tire/wheel well gap front and rear with the car on your desired suspension height setting (in my case low)

    Checking by eye I noticed that my car was higher in the front than the rear. I had previously reported this to my Service Center but nothing was done. Not completely trusting my eyeball method, I took some measurements with the suspension in the lowest setting. I placed a thin, flat 12” ruler on the top of the front and rear tires and measured the distance from the top of the ruler to the bottom of the wheel well opening. Sure enough there was a substantial difference:

    Front gap 1.75”
    Rear gap 0.875

    Conclusion: The difference was real and I needed to lower the front much more than the rear.


    2.Decide how small a wheel well gap you want and thus how much you’ll need to lower the car

    As I was lowering my car for appearance and wanted no compromises to handling or potential problems from lowering it too far, I decided to lower it enough to achieve an even front and rear wheel gap of about ½ inch at the lowest suspension setting. This meant that I’d need to lower the car about 1.25” (31.75mm) in the front and .375” (9.7mm) in the rear.


    3. Calculate how much longer the adjustable links need to be than the stock links to be to achieve the targeted lowering at the desired suspension height setting

    The stock links measure as follows from ball end to ball end (as shown in the photo).

    Front: 65.08
    Rear: 84.83

    IMG_0277.jpg

    IMG_0280.jpg

    For my adjustable links 1mm of additional link length lowers the car by 5.6mm (I’m not sure if that’s the case for all adjustable links but that’s what the instructions for mine indicated). With this information it’s a simple calculation to determine how much longer the links need to be than stock to lower the car to your target height. In my case the front links needed to be 5.67 mm longer than stock (31.75/5.6) and the rear links 1.7 mm longer (9.525/5.6). That results in new link lengths of 70.75 mm front and 86.5 mm rear. I set the adjustable links to these lengths (ball end to ball end) and locked them in place with the lock nuts.

    4.Set the adjustable links to the length specified by your calculations and install them.

    If your calculations are accurate when you lower the car after installing the properly set lowering links the car height front and rear should be spot on with no adjustments necessary. That was my case when my car was lowered.

    DSC_5830.JPG

    DSC_5835.JPG

    DSC_5833.JPG

    By the way, installing the links front and rear is much easier to do if you remove all of the wheels. You can reach the front links with the front wheels on but the installation is more difficult, especially attachment of the clips that lock the link balls on the socket. Make it easier on yourself and remove the front and rear wheels.

    DSC_5841.JPG

    DSC_5842.JPG

    Will post more photos tonight.
     
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  2. lolachampcar

    lolachampcar Active Member

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    Very nice and thank you for the details.
     
  3. artsci

    artsci Sponsor

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    My thanks to you -- your posts gave me the confidence to do this.
     
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  4. fadkar

    fadkar Member

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    That looks perfect! Thanks for the write up. Was the ride quality affected in any way? To lower my mustang, I swapped out the springs and dampers, so obviously the ride quality deteriorated when compared to stock.
     
  5. PaulusdB

    PaulusdB Mayor Gnomus Vintage Limb

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    I'm surprised to read that you decided the amount of desired lowering by measuring the gap between wheel and the wheel arch bodypart.
    Wouldn't it be more advisable to use ground clearance measurements (e.g. from the battery pack) for that?
     
  6. NSX1992

    NSX1992 Member

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    #6 NSX1992, Mar 23, 2015
    Last edited: Mar 23, 2015
    I lowered my red P85D about 3/4" with adjustable links myself. I found it easier to measure the changes by measuring between the floor and the highest part of the wheel well. My dimension is 27 3/4" at low setting. I did lower the fronts again by an additional turn after my initial attempt. Yes it is much easier to first take the wheels off. The rears are even easier as there is more room. I have not noticed any differences in ride quality. My ground clearance is 3 3/4" in low and 5 1/4" in very high.
     
  7. artsci

    artsci Sponsor

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    #7 artsci, Mar 23, 2015
    Last edited: Mar 23, 2015
    I did this with full knowledge of the ground clearance specs. But as my op notes I did this for appearance , which is why the fender gap was my concern.

    Remember, when the car first came out the low setting was .75 inches lower than it is now, until the famed fire battery episode, when Tesla defensively raised the low setting. So I've just close-to-restored the original settings. Plus my car (and maybe others) had this peculiar difference in the front and rear height. I just lowered the front to make it consistent with the rear, which I lowered only .375" This difference was also apparent in the fender arch to ground measurement I took but didn't trust, as I thought they could be explained by body design qualities.

    Another benefit may be slightly improved aerodynamics and slight improvements in range.

    My car goes into the shop next Tuesday to have the rear camber checked and reset if need be. I'll measure the ground clearance at that time and report it on this thread.

    The ride quality is the same.
     
  8. arijaycomet

    arijaycomet Member

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    Awesome thread, GREAT pictures! Thanks for sharing.. and yeah lolachamp's details have been so helpful for me. If it weren't for him I'd not have lowered my 85, and wouldn't be planning the same with my 85D. I'm not sure how I want to approach the 85D yet for lowering but it is definitely in the works. I'm curious to hear what you find out from a camber standpoint after this amount of lowering. I think it looks PERFECT so I want to know how well your alignment goes without the rear upper arms to correct the rear camber. Keep us posted!

    - - - Updated - - -

    Also what links are these (brand, where you bought, price)... my 85D is in transit but nothing says I can't order up some links right now. I might copy your purchase ... because my car is red too LOL ;) ;)
     
  9. artsci

    artsci Sponsor

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    Here's where I bought the links. The shop thinks lowering the rear on .375" won't affect camber much but I'll find out when I take the car in on Tuesday for an alignment check.
     
  10. drees

    drees Active Member

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    Nice write-up!
    A couple things to keep in mind when looking at wheel gap:

    1. It's usually easier to measure the distance from the ground to the highest point on the fender arch.
    2. Tesla most likely designed the car/suspension to ride with less fender gap in the rear than the front. Nearly all cars are designed this way from the factory. The proper measuring point going by the book uses suspension reference points or frame reference points to the ground, not the fender. The official ride height measurements has been posted somewhere here before - here's one post, but it doesn't note which suspension bolts are the reference points but shouldn't be hard to figure out.
     
  11. ToddRLockwood

    ToddRLockwood Active Member

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    Artsci, I assume that you had the car on a lift to do the installation. Is there a desirable height setting to have the car in while doing the installation? Jack mode turned on?
     
  12. LuckyLuke

    LuckyLuke Model S P85DL

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    It should be set to very high:
    ImageUploadedByTapatalk1427198665.212879.jpg
     
  13. mnx

    mnx 2013 P85

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    My car is lower in the rear than the front. I took measurements and they range from 4 3/16" on one side of the rear and 5" in the front (battery pack to floor). I have my set of adjustable links arriving any day now. Is battery pack -> garage floor the measurement I should be taking when I adjust the ride height or is it better to measure from the floor to the middle of the fender?
     
  14. artsci

    artsci Sponsor

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    #14 artsci, Mar 24, 2015
    Last edited: Mar 24, 2015
    I set the suspension to very high before the lift arms were placed on the jacking points, then lowered the car to normal, and placed it in jack mode. When you install the links the suspension height setting doesn't matter as the lowering is the same at all levels.

    - - - Updated - - -

    If you're looking for appearance and the stance of the car the fender gap method is best, although I have to confess that a consistent ground clearance from front to rear might yield good results. The front and rear mid fender to ground measurements are not the same, owing to the design of the car body. So you can't use that method -- if you made them the same the car would be angled down or up (not sure which).
     
  15. artsci

    artsci Sponsor

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    The head of Airmatic, the British company that makes the lowering links I used, called me today (from the UK no less) to check on how the installation went. This because I had emailed him with a few questions prior to the installation. Now that's customer service!
     
  16. scottm

    scottm Active Member

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    artsci I'm surprised you didn't approach this problem by looking at the sensor electronics first... if that's just a potentiometer in there then a series resistor (make it a potentiometer too) on the wiper pin might be all that is needed to add resistance ... if adding resistance is the right formula for dropping height.

    Any idea what the electrical interface of the sensor is to the computer it's talking with?
     
  17. lolachampcar

    lolachampcar Active Member

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    He is some data from a MB suspension lowering module
    New Page 1

    You can use resistors to bias the results but keep in mind that one side must be biased "up" in voltage while the other "down" :)
     
  18. NSX1992

    NSX1992 Member

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    artsci Using the fender gap method vs the distance from the floor to the fender lip will yield identical results assuming the front and rear tires are the same diameter. Think about it, adding 1" from the top of the tire to the tire diameter is the same as the distance to the fender lip with an 1" clearance above the tire. Mine sits almost level and the front and rear arches are the same.
     
  19. AMPUP

    AMPUP Member

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  20. artsci

    artsci Sponsor

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    As there are no photos or details about those links it's hard to determine the difference. But my guess would be cosmetics and not function.

    - - - Updated - - -

    I stand corrected.
     

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