So I found an old tweet by Elon that reducing the tire pressure to 39 would soften the ride but lose some range. I have the 21 Uberturbines. Has anyone tried this yet and if so what was range loss? Currently running at 45 psi and ride is hard.
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Elon's Tweet on Tire Pressure
- Thread starter LasVegas2019
- Start date
MrTemple
Member
Drop 3 or 4psi. It’s a no brainer.
Running at the door sticker on ANY vehicle will make for a VERY sharp and bumpy ride.
They do that because that’s what the EPA uses for mileage tests (gas or electric), and it squeezes out a bit more range at low speeds. (At high speeds plowing through air blows that change out of the water.)
I dropped my Inductions to 38psi (cold) from the door-rated 42psi and the ride is so much more comfortable.
Haven’t noticed any change in handling. Tires look equally inflated. 38psi is still plenty to avoid wear issues.
Haven’t noticed any change in real-world efficiency (though haven’t tested it), so it’s probably under a percent or two tops. Which is unnoticeable for daily driving, and only going to mean at the most 0.5-1% lower supercharger arrival on road trips, which works out to under a minute more charging.
So even on road trips I’ll probably leave it. I can’t imagine I’d trade 8 hours of comfort to save half a minute on a road trip.
(IMPORTANT: Always measure and adjust cold tires before driving! 38psi cold can be 42psi or more after driving on a mild day.)
Running at the door sticker on ANY vehicle will make for a VERY sharp and bumpy ride.
They do that because that’s what the EPA uses for mileage tests (gas or electric), and it squeezes out a bit more range at low speeds. (At high speeds plowing through air blows that change out of the water.)
I dropped my Inductions to 38psi (cold) from the door-rated 42psi and the ride is so much more comfortable.
Haven’t noticed any change in handling. Tires look equally inflated. 38psi is still plenty to avoid wear issues.
Haven’t noticed any change in real-world efficiency (though haven’t tested it), so it’s probably under a percent or two tops. Which is unnoticeable for daily driving, and only going to mean at the most 0.5-1% lower supercharger arrival on road trips, which works out to under a minute more charging.
So even on road trips I’ll probably leave it. I can’t imagine I’d trade 8 hours of comfort to save half a minute on a road trip.
(IMPORTANT: Always measure and adjust cold tires before driving! 38psi cold can be 42psi or more after driving on a mild day.)
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There's also a balance with tire wear. I don't expect my tires to last long anyway, but taking out some pressure will likely accelerate tire wear.
Flybuddy
Member
The ride on low profile tires will not improve much with lower pressures due to stiffness. Pressures listed on the sides of tires are for max weight and generally well over recommended door sticker pressures. (you might want to add pressure for towing or higher than normal loads in vehicle). Lower pressures do add more flex to the tire. Here's a video of a gopro inside a tire.
MrTemple
Member
True, but 4” sidewall is not exactly low profile.
You DEFINITELY feel the difference with the Inductions.
I went down to 39 and there is a noticeable difference from 42. Much better ride. I have the 21 Uber's
I have a MY with 20” induction wheels and I recently went on a road trip to Las Vegas from LA. When i left LA i set the tires to 42psi as suggested, however i averaged 370 wh/mi with 2 people. When i got to LV where it was 115F the psi went up to 47 but i averaged a much higher wh/mi to like 420wh/mi.
I then left some air out to 44psi at 115F. When i got back to LA where temp was around 90s the psi dropped to 38psi, however i was averaging 270wh/mi rated efficiency when coasting at 75mph.
I hope this is insightful for you guys but i will see what 36 psi will affect city and hwy efficiency.
Tesla specifies tires with an extra load (XL) rating for the tires on the Model Y. XL rated tires, as opposed to standard load rated tires, require 41/42 PSI. Always measure, adjust tire pressure when the tires are cold. This is usually best done out of the sun when the vehicle has been parked for at least 3 hours. Early morning is a good time to check the tire pressure. The recommended tire pressure is always found on a label on the vehicle's A pillar by the driver's door. For the Tesla Model Y the specified (cold) tire pressure is 42 PSI front and rear.
(Note: The tire manufacturer specifies the maximum tire pressure molded into the sidewall of the tire. For the Model Y the maximum rated tire pressure is 51 PSI (this is also a cold tire pressure number.) It is not a problem if the warm tire pressure reaches or slightly exceeds 51 PSI. The is a large margin of safety built into the design of the the tire. The tire would have to be significantly over inflated by ~20% before it would be a concern.)
You don't want to adjust the tire pressure after the vehicle has been driven; as you noted the warm tire pressure was ~5 PSI higher. This is normal, not an issue or in any way dangerous. What is dangerous is driving with significantly under inflated tires. This causes the tires to heat up more and is a leading cause of tire failure and blowouts.
Now that you are back home, set the cold tire pressure to the specified 42 PSI Front and Rear. You can experiment with varying the tire pressure, up or down, by 1 to 2 PSI with no concern. (I have found that I prefer the tire pressure of my Model Y set to 43/44 PSI cold, I feel the ride improves.) FWIW lowering the tire pressure will not improve driving efficiency, just the opposite. Rolling resistance can be somewhat reduced and efficiency improved by raising the tire pressure at the expense of the ride comfort. This is also true for ICE vehicles.
Based on my tire pressure measurements (always measured when the tires are cold) using a good quality aftermarket tire pressure gauge, the Tesla Model Y's built-in tire pressure monitoring system (TPMS) is accurate to with 1 to 2 PSI. This is good enough daily use, confirming the tire pressure has not changed due to a slow leak in one tire. The Tesla Model Y's TPMS turn off when the Model Y is parked, to get a reading you must start driving. The Tesla TPMS tire pressure readings will be most accurate within the first half mile to one mile after starting to drive, before the tires start to warm up.
The reason your Model Y energy usage (Wh/mi) was over 400 Wh/mi or while you were in in Las Vegas was not related to any increase or decrease in tire pressure. The Model Y's HVAC system, the air conditioner had to work much harder in 115F temperatures to cool the battery pack, maintain a comfortable cabin temperature. Back in LA, where the temperature was ~90F, the Model Y AC system does not have to work nearly as hard to cool the battery pack or the passenger cabin.
Do you have any after market tinting on the glass of the Model Y. The better tint films can significantly reduce the thermal transfer for the passenger cabin.
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Hey thank you for your insight. I do tons of city driving in LA and with 42 psi cold i do not always achieve 270wh/mi rated efficiency and i always precool the cabin when its hot.
I have a shade for the sun roof and 3M Crystalline all around. I was driving in Vegas with Cabin temp set to 73F.
I came from a LR Rwd Model 3 and i am noticing the difference. With my M3 with 39 psi i can achieve rated 240wh/mi easily with driving 40 mph steadily.
I am definitely curious what wh/mi and psi combination people are getting between 70 to 90 ambient temperature.
When driving in the warmest part of the day do you turn on Recirculate Cabin Air in the Climate Control Settings? The AC won't have to work as hard to maintain the cabin temperature when the cabin air is being recirculated. (Even when Recirculate Cabin Air is set to ON there is always some fresh air being sent into the cabin.)
The Tesla Model Y Voice Command can be used: "Recirculate" will turn on Recirculate Cabin Air, "Fresh Air" will turn off Recirculate Cabin Air. I don't leave Recirculate Cabin Air set to ON all of the time, especially in cooler weather, as the humidity can get trapped inside the cabin. This can cause the windows to fog up.
Most of my driving in my Model Y is local, at speeds under 45 MPH. I have my tire pressure set to 43 PSI (cold) I do not have any aftermarket tint installed in my Model Y. I do have a sun shade with the mesh installed. My typical Wh/mi is 244 Wh/mi (in the AM) and a bit higher in the PM during the warmest part of the day. My lifetime Wh/mi stands at 268 Wh/mi. Maryland is not Las Vegas or even Los Angeles as far as high temperatures, sun but July is typically the warmest month here. High temperatures typically are above 90F, up to 98F. In warm weather I always precondition my Model Y for at least 5 minutes. I have the Climate Control set to Auto, 70F. I will turn Recirculate Cabin Air on and off depending on the outside air temperature. When the outside temperature 88F or higher I turn on Recirculate Cabin Air if I remember.
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mackgriggs
Member
I can't believe I just saw the recirculate button on the A/C menu...I've been driving with it off for a year!
If you override, it will change the A/C setting to 'manual' though, not that much of a problem I think as it will still maintain temperature. Note that in 'auto' mode it will switch it on and off automatically when needed.
I think there's a flaw in the way the 'auto' settings controls the recirculation in very high ambient temperatures - it does switch it on initially when the interior is hot (makes perfect sense as it's the quickest way to cool down). However, even when it's 115F outside, and the interior temperature has stabilised, it will switch it off, to the point where it's unable to maintain the set temperature. Also agreed with jcanoe on the fact that switching it on does reduce energy use.
In my 2020 Model Y when I set Recirculate Cabin Air to ON the Climate Control system remains in Auto mode.
Will give that another try, I'm almost certain on my 2020 Y it doesn't (but it would not make sense if one vehicle behaved differently than the other).
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