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Model S Ride Height / Clearance

After seeing the recurring questions about the ride height of the Model S and given that there is no quantitative answer yet, I decided to set out to determine an estimation based on what we have seen so far.

The way I measured ride height was by measuring distances in photos from Tesla's gallery. I needed a point of reference -- something that I could determine the actual size of so that I could determine the scale of the object and estimate the size of other objects at the same depth in the image. For that, I decided to use the wheel's lug pattern. It's a five-bolt pattern of which there are several different sizes. Specs are listed here: http://www.tirerack.com/wheels/tech/techpage.jsp?techid=92. The question was which one is it? Some of those lug patterns are much more common than others. I can't say I guessed correctly for sure, but the value I chose was 5x100 (or 5x4.0 in inches). My reasoning was that:

  • It made the wheels come out to nearly exactly 20" in diameter which several sites have sited as the wheel size.
  • It is the smallest of the five lug bolt patterns, so if anything my estimations would be too small, not too large.

The pictures I used to measure from were http://www.teslamotors.com/models/gallery/6307 and http://www.teslamotors.com/models/gallery/5082. I first measured using the silver / grey car that is at an angle and only measured near / around the front passenger wheel to avoid messy perspective calculations that could be wrong depending on the setup of the camera that took the shot. Then I measured the picture of the maroon car (most likely the prototype many of us have seen in person). I measured each car independently, establishing scale for each on separately.

Problems with this method:

  • I made several estimations / guesses, so numbers are likely off -- especially if I misjudged the bolt pattern.
  • These are all alpha or prototype cars and ride height may change.
  • Sub-pixel measurements were made and that will induce a margin of error. Where I included digits after the decimal point, they're not worth anything.

Tools used:

  • The images from the links above -- download the original from the link above the image.
  • Inkscape to load the images and take measurements at a sub-pixel level (I just drew a line while recording how many pixels long the line was)
  • A calculator to determine scale and to scale up measurements from their pixel values to inches

Feel free to remeasure and contradict my results -- I don't claim to be an expert. Also, before you respond saying that this method is wildly inaccurate, you're right -- it is. It's only meant to give us a better idea of the clearance than we had before.

Results:

Silver Car
Maroon Car

Lug pattern
45 pixels
22.4 pixels

Scale used
11.25 pixels = 1 inch
5.56 pixels = 1 inch

Wheel size
220 pixels / 19.6 inches
111 pixels / 20 inches

In front of front wheel
Couldn't see well enough
30 pixels / 5.4 inches

Behind front wheel
53 pixels / 4.7 inches
25.4 pixels / 4.5 inches

Base of door near hinge
80 pixels / 7 inches
39 pixels / 7 inches

End of door near midpoint between wheels
N/A (perspective)
45 pixels / 8 inches

Your estimate for the "Clearance behind front wheel" aligns nicely with the 4.46" that Tesla has published here:
http://www.teslamotors.com/models/faq

Which makes your other numbers even more plausible. I would not give anything to the Maroon Car alone, it's really just a show car, but the fact that your estimates align pretty well for both cars lends additional credibility.

Hi,

I know that there has been a lot of concern voiced regarding the low ground clearance. How big of an issue is this really? Aren't there a number of other luxury sedans that have similiar or lower ground clearances? Would an adjustable suspension help, and do we know whether Tesla has any plans in this area?

Thanks.

Larry

It could be an issue to people who frequently drive in areas that have bigger changes in slope over short distances. My current car does not have any problems with this, but it used to be lower than it is now (my suspension is adjustable). Before I raised it from its previous setting, I did bottom out a few times. At the lowest, my car was probably about as low (maybe lower) as the Model S, however the car also is not nearly as long as the Model S.

I think the Model S high enough that it's not really a deal-breaker for most people, but it is certainly something to keep in mind while driving and definitely something to know before a decision to purchase is made. The biggest concern for most people would be steep driveways and large speed bumps.

Some people were also worried about the curb clearance for parallel parking. However, with around 8" of clearance towards the end of the door, I don't think that would be a problem except with crazy-tall curbs.

The main focus of the post was to get some numbers out there, even if just estimates so that people can have an idea about what to expect until we have more concrete numbers.

Before doing a lot of brain exercise, you just might want to wait for the oct 1 event and hope somebody brings not just a camera but also a measuring tape.

@Volker.Berlin, mwu I agree with you. It really started to bug me that I don't see the ground clearance being that small in that video with Roadster and Model S together, and your figures match better with my impression of the vehicle.

I basically agree with Ad van der Meer. Especially with all the ongoing changes, the only way to get a reliable measurement is to measure the latest model at the Fremont plant Oct 1. However, this is a fun academic exercise, so I just wanted to contribute one of several measurements I made when I was at Santana Row a few weeks ago. The span of the side windows from back to front is 72". Maybe you can use that to help validate some of your other numbers.

Side Window Span

@Ad van der Meer, My original post makes it sound like I just up and did the work before posting, but I actually performed the work a while ago and just had it sitting in a text file for a while. I was cleaning up my computer, found the file, and decided to post the data. I did this work before the Oct 1 event was announced. If I hadn't done the work already, yes, I would be waiting for the Oct 1st event before doing that work. Besides, I don't find doing a little mental exercise an annoyance. It's quite the opposite for me as a software engineer actually.

@Schlermie, From your picture, it looks like the measurement was from silver trim to silver trim -- going right over where the side view mirror is. If I do that, I get about 400 pixels which converts to 71.9 inches. That's pretty close.

However, If I measure the clear window segment -- from after the side view mirror to the beginning of the tinted area at the back, I get 313 pixels which comes out to 56.3 inches.

I'm not sure which way you had measured the exhibit. One thing to consider for accuracy is that my scale calculation was based on the bolt pattern on the wheels which is a small distance. That isn't as much of a problem measuring the distances under the car because they are also small distances. However when using the same scale calculation created from a small distance to determine length of a much larger distance, any error will be multiplied many times.

@mwu, My measurement was from silver trim to silver trim, as you described, so your 400 pixel translation to 71.9 inches is pretty dang accurate.

In the FAQ on the Model S, Tesla lists the ground clearance as 4.46".

Question is where they measure that lowest point. If it is for example between rear tires caused by engine protection then it is way less vulnerable spot to hit speed bumps/steep slopes than middle of the car. It might be the front of the car which goes lowest. That could hit the curb if driven too close in parking, but usually wont hit the speed bumps and slopes because front tires start to lift front before it hits the ground (front tires are not too far back). If it is the middle of the car where batteries are then those slopes might be a problem.

Right, Timo. What we actually want to know, is not ground clearance.

"Ride height (ground clearance or simply clearance in British English) is the amount of space between the base of an automobile tire and the underside of the chassis; or, more properly, to the shortest distance between a flat, level surface, and any part of a vehicle other than those parts designed to contact the ground (such as tires, tracks, skis, etc.)."
http://en.wikipedia.org/wiki/Ground_clearance

What we actually want to know are "Böschungswinkel" (usually different for front and rear) and "Rampenwinkel". But what is that in English?

"Böschungswinkel":

"Rampenwinkel":

(let's hope the img tag works as expected...)

Boeschungswinkel = slope angle/degree
Rampenwinkel makes less sense in english but the picture says it all.

Maybe traverse angle.

Front angle is about 25 degrees
Back angle is about 28 degrees

From the diagram, it looks like rampenwinkel is measured using the midpoint between the wheels along the chassis as the vertex with the top portion of the angle coming from the back wheel lining up with the midpoint and the bottom portion of the angle coming from the front wheel lining up with the midpoint. Using that method, the rampenwinkel measurement is about 12 degrees.

The last angle comes out so low because despite the ride height not being all that small, the distance between the wheels is fairly long.

Approach, departure and break over angles are what we call them in the off road vernacular.

Approach Angle-The approach angle is the angle drawn from front of the tires to the front bumper. The greater the angle the steeper the ledge you can go up to without the bumper hitting the ledge before the tires. If the front bumper sticks out too far it will hit the rocks before the tires have a chance to crawl up. And going down steep ledges the nose will bury in the ground before the wheels reach level ground.

Departure Angle-The Departure Angle is measured from the back of the rear wheels to the rear bumper. If the rear bumper sticks out too much the rear will drag in the dirt when going up ledges and drag against ledges after going down.

Break-over angle-The Break-over angle is the smallest possible angle when measured from the wheels to the underside of the vehicle. If the break-over angle is too small then as your vehicle crests the top of the ledge the vehicle will bottom out on the edge of the ledge.

Here is the data for two cars that are remotely comparable to the Model S. @mwu, I think your estimate for approach angle and departure angle are way off, they cannot be correct.

Jaguar XF
Approach: 14.6 deg. (unladen), 13.4 deg. (fully loaded)
Departure: 16.9 deg. (unladen), 14.0 deg. (fully loaded)
Ground clearance: 140mm

Aston Martin Rapide
Approach: 8.9 deg.
Departure: 18 deg.
Ground clearance: 138mm

(Source: Email request to manufacturer)

Very possible -- it's all from an image and I don't like how I had to measure angles.

Model S has quite round front and back ends if you look at them from above, it lies a lot in the pictures unless you get a picture directly from side and preferably closer to the point you are measuring.

I can't see anyone getting down on the floor and measuring all these angles at the event... but some nice clear pictures of the clearance could give us a better idea as to what the angles truly are.

May I suggest that someone just brings his portable laser scanner and creates a digital 3D model? That would help a LOT! :-D

Lol, yea, or even better I bet Tesla already has 3D models -- maybe they'll share :)

The example above is a Suzuki offroad miniSUV, so it's designed for lots of clearance. Completely different from a sedan.

correction: mini truck, of course. Similar frame to its older Pilot(?) models.

Pretty sure they were just using those visuals to explain what the angles measure.

Right. And another important point is how close the lowest point is from the axles. If it's 4.x within a foot of the axles and at least 6 inches everywhere else, it probably won't be a problem.

"The optional air suspension automatically responds to speed and road conditions. As Model S accelerates, it lowers the vehicle for optimized aerodynamics and handling. Lower or raise Model S using the touchscreen to unload cargo when parked."

That solves that problem.

Where was that from??

new features page has been added
http://www.teslamotors.com/models/features

Neat. I wonder how expensive that option will be.

The specs now say 6 inches unladen ground clearance. This was my report after the Detroit show. I hope it is enough for the snow in South Bend Indiana which averages 72 inches a year.


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