I've noticed now that the weather has become gloomier and the ground is covered with a mix of powdered salt and rainwater that the Model S tends to kick up a lot of that grossness onto its own backside. Is this due to its aerodynamic shape or because there is no exhaust to "blow away" the ick? Next up on features: a protective bubble surrounding my car that protects it from the outside world (think hamster wheel) but until then, weekly car washes it is!
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FLDarren
Member
That's usually the dirtiest part of my car besides behind the tires. I have the LED license plate bulbs and they really let the dirt show at night.
JakeP
S P4996 ==> P02547
I use a California Car Duster to keep that back end clean, it is amazing how much dust adheres back there. A combination of airflow and electrostatic adhesion, I would wager.
Newscutter
Member
Even more interesting (to me) is how CRISPLY the road grit will deposit itself on the trailing edges-- like pin striping!
See pic (I can't get it to embed)
Tesla Pittsburgh on Twitter:
See pic (I can't get it to embed)
Tesla Pittsburgh on Twitter:
Todd Burch
14-Year Member
A little aerodynamics:
Ironically, a more aerodynamic back side should lead to less dirt on the tail, since better aerodynamics would imply less of a pressure drop immediately behind the car, which in turn would have less of a vacuum effect to suck grime onto the tail.
However, having said that there are a few factors:
1) Yes, the shape of the rear seems to cause air patterns that tend to pull dirt up off the road and onto the tail. All Model S's are subject to this. (It's ok...AFAIK we still can claim the lowest drag coefficient of any production car).
2) The smooth underbelly of the car causes more laminar (smooth) flow underneath, as opposed to an ICE which causes more turbulent flow. This yields better aerodynamics, but may also contribute to the "coordinated" lifting of grime from the roadway.
3) A possible contributing factor: The high torque produced at low speeds coupled with the lack of mud flaps may fling more grime up, and since this happens at low speeds, there is less surrounding airflow to blow the grime away from the car.
Ironically, a more aerodynamic back side should lead to less dirt on the tail, since better aerodynamics would imply less of a pressure drop immediately behind the car, which in turn would have less of a vacuum effect to suck grime onto the tail.
However, having said that there are a few factors:
1) Yes, the shape of the rear seems to cause air patterns that tend to pull dirt up off the road and onto the tail. All Model S's are subject to this. (It's ok...AFAIK we still can claim the lowest drag coefficient of any production car).
2) The smooth underbelly of the car causes more laminar (smooth) flow underneath, as opposed to an ICE which causes more turbulent flow. This yields better aerodynamics, but may also contribute to the "coordinated" lifting of grime from the roadway.
3) A possible contributing factor: The high torque produced at low speeds coupled with the lack of mud flaps may fling more grime up, and since this happens at low speeds, there is less surrounding airflow to blow the grime away from the car.
JakeP
S P4996 ==> P02547
Todd Burch
14-Year Member
Update: Paying more attention to the geometry of the body around the rear wheels, I'd say my theory in #3 above is an unlikely contributing factor--so #1 and #2 seem to be the primary causes.
Even considering the RWD?
When driving over snow, the license plate can quickly become blotted out. I'd rather not get stopped for a warning for this. Is there a more convenient solution than frequent cleaning stops?
Just in case someone's not familiar with the phenomenon, here's an image lifted from the Cross Country Rally video.
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I think every car I've owned has attracted more dirt at the rear than the front. I know my Roadster, Porsche Cayman, Porsche 356A, Toyota Prius, Subaru Forester, Mini Cooper and Ford Merkur all have displayed that characteristic. The Model S seems typical in that regard.
JakeP
S P4996 ==> P02547
What are your thoughts on electrostatic influence? The motor and drive train are within inches of that rear cowling, and I know they are magnetically shielded, but I still can't help but think this is a contributing factor. The way that back end is a dust magnet just makes me think "static cling"!
Todd Burch
14-Year Member
green1
Active Member
I'm with ecarfan on this one... show me a car that DOESN'T have this issue. I've never seen one.
@liuping, four of the seven cars I listed in my post were white or very close to it, and I certainly noticed the greater amount of road grime in the rear compared to the front. I always wash my cars myself, I never take them to a car wash, so I do take note of where the dirt is.
mknox
Well-Known Member
Yes, but it is definitely worse on the Model S than anything else I've driven. Not really an issue except that it really interferes with the rear view camera. Even if I wipe it off, it's blocked again within a few miles on salty/wet winter roads.
green1
Active Member
There are really only 2 solutions to help keep the back of a car clean.
1) mud flaps. The bigger the better.
2) wind deflectors, you see these occasionally on station wagons, mini-vans, and SUVs, most are useless, but some direct air down the back just right to keep it clean.
1) mud flaps. The bigger the better.
2) wind deflectors, you see these occasionally on station wagons, mini-vans, and SUVs, most are useless, but some direct air down the back just right to keep it clean.
