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3D printed lowering links

Discussion in 'Model S: Driving Dynamics' started by scottm, Oct 2, 2016.

  1. scottm

    scottm Active Member

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    You heard that right! I printed a set of adjustable lowering links for my S and the car is now riding on them.

    I decided to dial in the new height so that Normal sits where the car previously was on the Low setting. And low is now a bit lower.

    IMG_9380.JPG IMG_9382.JPG IMG_9377.JPG
     
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  2. scottm

    scottm Active Member

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    #2 scottm, Oct 2, 2016
    Last edited: Oct 2, 2016
    I modified (grinder) a panel fastener puller tool to help get the stock links ball ends off the car.

    You want the inner spanner to be a bit more than 10mm at the widest.

    The black tape prevents marring finishes when you pry against something.
    IMG_9383.JPG
     
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  3. scottm

    scottm Active Member

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    You might need to cut away a bit of the front fender liner so the the new links can fit without hitting.

    For lowering the car, the links need to be longer than stock. When the car is on Very High setting one link end is pushed to its maximum reach toward the fender liner. That's where you need to trim. Here's how much I cut out.

    IMG_9387.JPG
     
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  4. scottm

    scottm Active Member

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    #4 scottm, Oct 2, 2016
    Last edited: Oct 2, 2016
    IMG_9390.JPG IMG_9392.JPG IMG_9396.JPG I made my links finger adjustable ... very handy for reaching in on the fronts and doing fine tuning of ride height.

    With the car on Very High, just reach in over the tire and adjust. No tools.

    I set these to achieve 4mm extra length (ball-to-ball) over the stock ones.

    To set the length slack off the lock wheel, turn the other wheel, then lock again. The longer plastic end is normal RH threaded hole accepting a bolt. Head of the bolt is embedded inside the shorter plastic end and is free wheeling on that side. The adjuster wheel closest to the short side is JB welded onto the bolt.

    When installing onto the car, I used a block of wood wedged in behind the green sensor arm when pushing the new link end on, with some sturdy thumb pressure force -- pop! It snaps onto the ball.

    (The greasy wet look on the suspension arm is anti-rust spray coating. Winters and salt here are wicked on all cars, even Tesla has some metal that is not aluminum and will rust!)
     
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  5. scottm

    scottm Active Member

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    #5 scottm, Oct 2, 2016
    Last edited: Oct 2, 2016
    I used stainless steel bolts and nuts, the hardware at Home Depot was a few bucks in total.

    Longer 2" bolts for the rear links, and 1 1/2" bolts for the fronts. It was hard to keep the front design compact enough to fit in that space.

    I wanted to be able to dial in the settings to achieve stock height. In order to do that, the fronts have to dial compacted as tight as everything can go. The rears have more room to breathe and no cutting away of liners the links are just sitting right there behind the hubs between two suspension mount points.

    Fit Details: the front Tesla links are 50mm ball to ball (centers). The balls are 10mm. The rear Tesla links are 70mm ball to ball.

    ABS plastic in my Printrbot Simple Metal 3D printer - this thing works like a champ. I've done other ABS parts for my Tesla (search dashcam mount on interior mirror).

    When the long end of the links were done printing I drilled and tapped them to fit the bolt threads.
    The short end is a special 2-part design that lets me drop the bolt head into the part, then cap it with another piece and those are ABS glued together so the head is encapsulated. The short end is not threaded, it lets the bolt spin inside. Everybody knows the links on the rear of the car have the ball caps pointing in opposite directions, no problem, the short end of these links spin 360 degrees around if you want and will not lengthen or shorten in doing so.

    The "lock nut" is an ABS wheel with good grips on it with a stainless nut embedded at the center of the wheel. Just so you don't need tools to adjust length. I used a tiny bit of butyl rubber sticky caulking compound on the threads buried in each plastic end to keep the bolt from freewheeling should the locking nut loosen off. That locking nut is not really needed... turning the adjuster wheel is very stiff to do.

    It took several design tries to get ball caps that would be durable and snap on. Once on, they move and swivel freely around the ball. Since these links do not transmit any appreciable forces these parts do not need to be metal.. they are simply "sticks" that move a sensor lever back and forth w.r.t the position of the suspension arm.
     
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  6. FlatSix911

    FlatSix911 918 Hybrid

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    Well done! Wish is was this simple to lower with coil springs :cool:
     
  7. scottm

    scottm Active Member

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    In doing this job, I found my Left Rear suspension height had not been calibrated correctly and I'd been riding low in that corner.. probably for a year !! (when drive train was replaced) . It was actually LOWER with the stock link than the new low setting for the other 3 wheels when the car is now set to low. Eesh.

    Ironically, I had to adjust that corner link to be shorter than the stock link to raise the corner. So technically, these are not just lowering links.. they can also raise the car :p
     
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  8. scottm

    scottm Active Member

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    #8 scottm, Oct 2, 2016
    Last edited: Oct 2, 2016
    Strange but true...

    At first, I replaced just one link on the front as I wanted to check the new ride height. With the longer link installed on the front right side and all other links on the car still stock.. I promptly jumped in the car and hit some ride settings.

    Blew my mind that the adjustable link set 4mm longer on that corner had no effect! The car set all corners to be what they were originally.

    It wasn't until I replaced the second link, this time the left front of the car... did the car start respecting the new longer links and the dropped the front accordingly. Rear links hadn't been done so the rear was riding in its original height.

    This suggests the car software will "ignore" one corner of the car if it suddenly starts responding differently than it did last time, or maybe with respect to the rest of the car.. for a given air adjustment input. It might assume an error (blander puncture, air leak?) or road hazard took out a link. Kind of a sanity mode to ignore a corner.

    No errors or indications inside the car tipped what was going on.

    When I was done all 4 corners, and did a couple drive cycles, back and forth, short run... I was able to adjust any given corner a bit one way or the other to dial in a uniform height. Some adjusted up 1/4" some down 1/4"..

    After doing this job, I think there's a tolerance that the car can achieve and it's precision is limited. My guess is plus or minus 1/8" to 1/4" is as accurate as it gets... so you can expect variance on measurements any given time and just be happy with that. Next time you might find that same corner +/- 1/4" different.

    I left the car tonight with the rears "jacked up" a bit maybe 3/4" higher than the front... I noticed the difference of headlights not projecting as far down the road. I will be adjusting them to be the same as fronts so I'll have a nice flat bottom to the ground.

    It's just a pain to adjust rears because the wheels have to be taken off.. each time. Jack mode on. And put back on again to test each adjustment. Jack mode off. Definitely not as easy as the fronts just reaching over the wheel to do. Air tools are your friend when doing rears. And don't bother torquing lugs to spec until you're all done.
     
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  9. scottm

    scottm Active Member

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    #9 scottm, Oct 4, 2016
    Last edited: Oct 4, 2016
    I was thinking of posting some lowering link 3D patterns on thingiverse like I did for this dashcam mount (Classic Model S mirror mount).

    To make it real simple, rather than adjustable links offering a set of different fixed length links to download and print the height you want, pop off the old links pop on the new. No fuss an no dial-in adjustments. Of course, you'd have to be happy with your current calibration and you won't be able to fine tune it out... but if you're wildly off in a corner like I was, you could print just one link in the next plus size up or minus size down to correct just that corner.

    Thinking sets ranging from -2mm through to +8mm in 2mm increments should do most needs.

    -2mm would raise the car (48mm ball centers front, 68mm ball centers rear)
    0 difference, stock link replacements (50mm front and 70mm rear)
    +2mm would lower the car (52/72 centers)
    +4mm lower it more (54/74)
    +6mm lower yet (56/76)
    +8mm lowest (58/78) these would start to look dramatically lower, probably for show, not daily driving.

    Mix and match at different ends of the car, or do whatever funky thing you need.

    Having a stock length set means you can return the car to stock (if you lose the original links) which is useful prior to bringing the car into SC when they might be recalibrating your ride height (after drive train work). If they recalibrate on lowered links you'll get a standard height car back... you'd have to upsize the links again to get lower.. a game of diminishing returns and shrinking space to grow links.

    Because this is for Model S, the rear (longer) links must fit balls pointing in opposite directions on the car. It's hard to print ball cups opening downward on the print bed, without a lot of supports inside the ball yuck. Instead of designing closed cups for the rear, I'd slice off the top of the cup - so it is open to snap onto a ball from either side of the link. These would look like "forks" that grab around a ball rather than cups that snap over the ball covering it. I tried this as a previous generation design and they do grab quite nicely. And since these are for the rear, and there's LOTS of space to install, I'd put a reinforcing beam around the ends... as additional holding power. Look a bit funny, but stronger...

    The front links can be printed with full cups at both ends, because the balls face the same way on the car, both ends can be printed with cups opening upward.

    ABS recommended. I find thicker layers (0.3mm) make a stronger product, yet they are uglier but so what. I'd like to hear your success with Nylon if you try that.
     
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  10. scottm

    scottm Active Member

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    #10 scottm, Oct 10, 2016
    Last edited: Oct 10, 2016
    Here's what the rear links look like, I'll post these up soon to thingi..

    I'm printing off a 74mm sample to install on my car to show the fit. I made the array of 68..78 in 2mm increments, you'll be able to download individuals.


    Capture.PNG

    ..And if you're a belt and suspenders kind of guy, I made these caps that press onto each end of the link after being installed on the car. This cap locks the link end onto the ball by preventing any spreading of the springable parts (which are necessary to allow snapping the link into place on the ball).

    You would not install a locking cap until you've settled on the right length of lowering for your liking. Because once they're on... the caps don't want to come off (they can be pried if they must). And the caps must come off before you'll be able to get the link off.

    Even without the cap at all, these links snap onto the ball strong enough and will hold anyway. Caps are optional IMHO.

    Capture2.PNG
     
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  11. scottm

    scottm Active Member

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    Front link fixed length array looks like this in 48mm ... 58mm sizes (ball to ball center)

    These are full cup ends that snap over the ball and cover it.
    Capture3.PNG
     
  12. Nismode

    Nismode Member

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    So, any photos of the new lowered look?
     
  13. Dithermaster

    Dithermaster Member

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    So cool!

    My P85+ has staggered 21" for summer and regular 19" for winter. I was going to swap them myself but Tesla said I couldn't because the Air Suspension needs to be recalibrated for each swap. It seems like these would remove that necessity for when the day comes that they want too much to do it (although I think they also do alignment during the Annual Service, which I can't do).
     
  14. scottm

    scottm Active Member

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    #14 scottm, Oct 10, 2016
    Last edited: Oct 10, 2016
  15. scottm

    scottm Active Member

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    That's a good point... these links will change the height of the car, but perhaps another calibration Tesla needs to do when you change wheel sizes (in addition to setting ride height) is to set the speedometer / odometer calibration because there will be perimeter difference of the two wheel sizes.
     
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  16. scottm

    scottm Active Member

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    Car is so dirty, I'm embarrassed to show it... but sure, when it's clean again I'll show what a model S looks like when the top of fender arches are dialed in at 28.5" inches from the ground (measured at wheel center)... it's a very good looking setting for the amount of gap around the wheel to body - very uniform and natural looking posture. IHMO the should have come this way from factory as "standard" height setting ... and probably did originally circa 2013 prior to the "road hazard upward adjustment"

    When the car is set uniformly using height of arch tops from the ground (all four corners equal), the body appears to have slight downward slope or tilt toward the front. Not so much that it looks 'jacked up' in the rear, but just enough to have an "alert and slightly aggressive stance that appears ready to pounce". (my words, how'd I do?! :p) It just looks more "ready".

    I'll measure the battery tray to floor height all around and see if it indeed differs front to back... or if it's just an optical illusion. No matter, I'm keeping my car this way, equal all around at 28.5" as the new normal / standard height. I'm finding headlights are aiming down the road just fine again. (Having had that extra inch dialed in at the rear for a while was noticeably pointing low beams into the ground too soon.)

    ..car handles noticeably different too (better) sitting at this height going around sweepers and such.. and even more so when I hit "LOW" setting... more like a go-cart. Incredible! I'm not sure how many G's I'm pulling when the tires start howling.. but it's well worth the lost rubber!
     
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  17. redi

    redi 2013 P85+ with HumanPilot Technology

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    You're probably very close. One guy measured his P85+ prior to Tesla neutering the ride height in v5.8 during Nov. 2013 (2 months after I took delivery of my P85+). He indicated his car was already lowered (lowering links) by about 1/2"

    Lowered P+
    Low Setting
    27 11/16 27 10/16
    27 12/16 27 15/16

    Another measured from the battery tray on a std height P85+.

    Version_____5.0______5.8
    Low_______4.46"____4.92"
    Std________5.30"____5.31"
     
  18. scottm

    scottm Active Member

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    OK, here's some photos ...

    This batch is of the car lowered using these adjustable links in the new "Normal" ride height setting.

    IMG_8286_NORMAL (Small).JPG IMG_8287_NORMAL (Small).JPG IMG_8288_NORMAL (Small).JPG IMG_8289_NORMAL (Small).JPG
     
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  19. scottm

    scottm Active Member

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    #19 scottm, Oct 23, 2016
    Last edited: Oct 23, 2016
    These are new Normal measurements.

    fender height in front is approx 28 3/4" (maybe 1/8 more)
    fender height in rear is approx 29 (maybe bit less at 28 7/8)

    In other words, it's pretty close to 28 7/8" all the way around the car.
    At this setting, how far is battery off the ground?

    battery tray rail height is shockingly level at 4 3/4" at both ends of car, front and back
    measured clearance from ground to "rail", using my zippo tape measure which is 1.5" height itself.
    you can see the measuring points on the car/rail that I selected, but it's the same all along (Tesla knows how to make a flat battery!)

    Front of car:
    IMG_8290_NORMAL (Small).JPG
    Rear of car:
    IMG_8291_NORMAL (Small).JPG
    Front, battery rail:
    IMG_8293_NORMAL (Small).JPG
    Rear battery rail:
    IMG_8294_NORMAL (Small).JPG
     
  20. scottm

    scottm Active Member

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    Everybody wants to see the car slammed... so without adjusting the links, I selected LOW ride height setting, and this is how it looks:

    At 25 feet away:
    IMG_8295_LOW (Small).JPG
    IMG_8296_LOW (Small).JPG
    IMG_8297_LOW (Small).JPG
    Taken from 100 feet away, long lens:
    IMG_8306_LOW (Small).JPG
     
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