Smart Air - Efficiency gained at highway speeds?

chriSharek · May 9, 2015

What is the efficiency gained by lowering the car at high speeds? Anyone know? Is it 1%, 2?

I'm ready to give up the air and go with the coils if I can get into an 85D instead of the 70D fully loaded. Any other thoughts on that?

jerry33 · May 9, 2015

It totally depends on the speed. The faster you go the more effective it is. However, there's no real data on how much because it's very hard to remove all the variables and just test for the ride height. The main reasons to get air are the clearance at low speeds and the ride. In general, people get coils because they want road feel and air for comfort and clearance.

DavidB · May 9, 2015

I'm biased, I suppose, but I'd hate to give up the air suspension. Even if there is no efficiency gain, the air suspension allows you to raise the suspension when you are driving in rutted roads or over road humps.

kuttakamina · May 9, 2015

Bjorn nyland did a video, and the gain was less than 1%

Todd Burch · May 9, 2015

With 35,000 miles on air and 13,000 miles on coils, I agree any efficiency gain is imperceptible given all other variables. Don't use that as your purchase criteria.

ChadS · May 9, 2015

I have the air suspension, and while I like it...it's just not that big of a deal. If I buy another one, I will likely get coils. I had a loaner with coils once and it was just fine. There could be a situation where changing the ride height could help, but there could also be a situation where more range helps. I'd favor the larger battery, but of course you are the one that has to look at your likely driving habits to see what would help more.

Cyclone · May 9, 2015

I was agnostic about air suspension vs. coils. If ordering new, I would get coils, but I wasn't going to ignore a car if it had air (I was looking at inventory cars too). I ended up with a CPO with air. I'll be fine with it on way or another. Btw, others here (including @tliving) have coils in the snowy NE have no issue - they even have RWD. As I have said to a few others, you can't make a wrong choice as long as your car starts with five letters... T-E-S-L-A.

Todd Burch · May 10, 2015

The reason coils aren't a problem with ride height is because the fixed height of a coil car is higher than the normal height of an air car.

I scraped bottom 3 or 4 times in my air suspension car. I have never scraped bottom in the coil car.

taurusking · May 11, 2015

I had to get a loaner car since my car was at the service center last weekend. The loaner had air suspension and I liked the smooth ride. However after driving for long distance there was not much difference and on uneven roads coil was better. However like many said before don't base your decision on the coils or air suspension. Go with what you like.:smile:

Andyw2100 · May 12, 2015

kuttakamina said:
Bjorn nyland did a video, and the gain was less than 1%

Lowering at what speed? And then driving at what speed?

Edit: Though I didn't think I'd be ale to, I found the video, and will watch it. For anyone else interested, it is here: Tesla Model S energy consumption normal vs low suspension - YouTube

And there's another one, at higher speed, here: Tesla Model S normal vs low suspension at 160 kph/100 mph - YouTube

What speed do people generally set as the speed to move to "low"? 55? 60?

Also I have checked the manual, and can't find an answer to this: at what speed will the car raise back to normal? Is it just the same speed? So, for example, if I set the car to change to low at 60 MPH or higher, does it automatically move back to normal ride height when I slow to 59 MPH?

Thanks.

Barry · May 12, 2015

Andyw2100 said:
What speed do people generally set as the speed to move to "low"? 55? 60?

Also I have checked the manual, and can't find an answer to this: at what speed will the car raise back to normal? Is it just the same speed? So, for example, if I set the car to change to low at 60 MPH or higher, does it automatically move back to normal ride height when I slow to 59 MPH?

I have mine set to go Low at 65+ mph. It seems to go back up to Normal at about 50 mph.

jerry33 · May 13, 2015

I set mine at 50 mph.

Andyw2100 · May 13, 2015

Barry said:
I have mine set to go Low at 65+ mph. It seems to go back up to Normal at about 50 mph.

jerry33 said:
I set mine at 50 mph.

Thanks, guys.

Jerry--At what speed do you think your suspension raises back to normal?

Thanks!

jerry33 · May 13, 2015

Andyw2100 said:
Jerry--At what speed do you think your suspension raises back to normal?

I haven't watched it carefully, but from what I've seen it raises as soon as you go less than 50 mph. So I suppose you'll save a bit of energy by setting it at 60 if the traffic speed during your commute oscillates between 45 and 55. You could also set it at always low, but then you have to be far more careful about speed bumps and such. Mostly I don't worry about this as I don't think the compressor uses all that much energy.

Blu Zap · May 13, 2015

Air suspension is lots more valuable than the lowering at speed. I can't imagine living without it. Driveways, speed bumps, parking lots where it get raised, mostly automatically through GPS. Importantly clearing curbs and parking wheel stops.

I do set my lowering at 70 mph. It goes back to standard around 45-50 mph. I don't have to think about it. It lowers on the freeway and goes back to standard when i take the off-ramp. Bjorn did do a test that showed around a 1% range improvement to lower the car at highway speed. Not a big deal around town. But on a long range trip with Superchargers, that would make a difference, since I tend to speed over the EPA rated range formula. (290 Wh/Mi.) I need all the help I can get.

100thMonkey · May 13, 2015

we did comparison test drives when trying to settle on which version of the D we were upgrading to. I came close to going with coil suspension after reading people's reviews but I decided to stick with air because I could tell a distinct body roll with the coil springs going into curves. I guess I've gotten spoiled driving air the past couple of years, you feel so planted. originally I had concerns about the long term costs of maintenance with the air but it seems that there just have not been issues so far, perhaps because Tesla decompresses the system when the car is off.

chriSharek · May 14, 2015

Would you mind responding to this poll? Just trying to fine tune my order. Thanks!

Smart Air - worth the $2,500 upgrade from coils?

brianman · May 14, 2015

Andyw2100 said:
At what speed do you think your suspension raises back to normal?

RTFM:

model_s_owners_manual_touchscreen_6.2_das_na_r20150326_en_us.pdf said:
• Very High. When set to Very High, the suspension automatically lowers to High when driving speed reaches 22 mph (35 km/h).
• High. When set to High, the suspension automatically lowers to Standard when driving speed reaches 34 mph (55 km/h).
• Standard. The Standard setting ensures optimum comfort and handling under all loading conditions.
• Low. Lowering the height can make it easier to load or unload cargo and passengers.

model_s_owners_manual_touchscreen_6.2_das_na_r20150326_en_us.pdf said:
You can adjust the speed at which the Air Suspension automatically transitions to the LOW ride height by touching Controls > Suspension > Automatic Lowering on the touchscreen. This setting is saved to your Driver Profile.

Andyw2100 · May 14, 2015

brianman said:
RTFM:

You know what? I did RTFM. And I said that upthread.

Show me where in what you posted the manual indicates at what speed the car raises back to normal, after having been lowered. When you can't, I'll accept your apology.

Edit: This is what I had written:

Andyw2100 said:
Also I have checked the manual, and can't find an answer to this: at what speed will the car raise back to normal? Is it just the same speed? So, for example, if I set the car to change to low at 60 MPH or higher, does it automatically move back to normal ride height when I slow to 59 MPH?

Thanks.

And then there were answers to that question that varied greatly:

Barry said:
I have mine set to go Low at 65+ mph. It seems to go back up to Normal at about 50 mph.

jerry33 said:
I haven't watched it carefully, but from what I've seen it raises as soon as you go less than 50 mph. (My edit--this was from Jerry, who sets it to lower at 50, so he was saying it lowered and raised at the same point, while the poster above had a 15 MPH difference.)

chriSharek · May 17, 2015

Blu Zap said:
Air suspension is lots more valuable than the lowering at speed. I can't imagine living without it. Driveways, speed bumps, parking lots where it get raised, mostly automatically through GPS. Importantly clearing curbs and parking wheel stops.

I do set my lowering at 70 mph. It goes back to standard around 45-50 mph. I don't have to think about it. It lowers on the freeway and goes back to standard when i take the off-ramp. Bjorn did do a test that showed around a 1% range improvement to lower the car at highway speed. Not a big deal around town. But on a long range trip with Superchargers, that would make a difference, since I tend to speed over the EPA rated range formula. (290 Wh/Mi.) I need all the help I can get.

The 1% equates to 2.7 miles on the 85D. Come on!? I'm torn because the long-term costs with the air are pretty significant. I'm convinced on the 19"s because they provide 3% more than the 21"s PLUS they last longer AND are cheaper to replace. But 3% is almost 10 miles of range on the 85D. That's significant. I don't see the 1%/2.7 miles would really make a difference.

Smart Air - Efficiency gained at highway speeds?

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