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Comment by madeofpalk | Hacker News Reader

Is someone able to explain this more?

"Default ground clearance" means the distance between the ground and underside of the car, yeah? How are they able to control that with software?

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Other responders answered well enough, but I'll add some additional info.

Tesla just started pushing out OTA updates to firmware 5.9 this week. One of the big improvements in it is bringing back the option to select a low height mode. When the problems mentioned in the article happened, they pushed out a rapid update that disabled the automatic low suspension setting entirely. Frankly, this upset a few of the vocal owners on the teslamotorsclub.com forums because they understood the risk and felt it was slight enough they preferred it versus the reduced handling and performance at a higher ride height.

The re-introduced low height is enhanced to allow the driver to set the speed at which it will change height. This is satisfying most if not all of those owners.

Driving a car that gets better as you own it instead of worse is a game changing model in my opinion.

All the suspension is electronically controlled for stability and responsiveness. Most expensive cars to that these days.

The software must tell the dampers to ride a bit stiffer stopping the car body being pushed lower at high speeds.

Traditionally with adjustable pneumatic 'springs' (rubber air bags) that inflate or deflate to change ride height, often in response to increased vehicle weight. Not sure if that is approach Tesla takes.

EDIT: Looks like Tesla does indeed use air suspension: http://www.teslamotors.com/de_AT/forum/forums/air-suspension...

Modern luxury/sports cars have active suspension systems that allow for adjustments in firmness, response, and in this case the ground clearance of the vehicle.

http://en.wikipedia.org/wiki/Active_suspension

Also note that some cars (the old Audi allroad) and last two generations of Audi A8 have airbags built into the suspensions at all four wheels that inflate and deflate to change the ride height.

This is different than simply adjusting the characteristics of the electronic suspension - this actually raises and lowers the car non-trivial amounts. I think a D3 A8 can raise up 4-5 inches from highway level to bumpy dirt road level...

I am genuinely curious what the raise/lower range for the tesla is - anyone know offhand ?

The Higher spec Model S' has active suspension that will lower the ride height at high speeds to reduce drag. The active suspension's control system was changed to lower it less.

The suspension in the Model S is computer controlled, so they just push an update to control it differently!

Digitally controlled suspension

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