New rims/tires and how Tesla estimate range

[Oyinko]

Hi!

I drive a Model 3 performance and recently swapped my 20'' wheels for a set of 18" TST Flow Forged Tesla Wheel mounted with Goodyear Assurance WeatherReady tires.

When I did swap the wheels, the computer detected new tires and I selected 18'' as the new tire size.

Since then, I find the range prediction a bit off compared to when I was running my 20" whees. I guess it makes sense because Tesla doesn't have any data on rolling resistance of the 18" TST Flow Forged Tesla Wheel mounted with Goodyear Assurance WeatherReady tires.

However, I'm wondering what kind of data they are currently using to estimate the real range of my car?

With the 18" TST Flow Forged Tesla Wheel mounted with Goodyear Assurance WeatherReady tires, I average 275 wh/mile at 65mph.

 

[animorph]

What are you looking at to get the range estimate? The battery display is just EPA "rated miles", an estimate of the available kWh's in the battery times a conversion constant to get miles of "range". Which has close to nothing to do with your range unless you drive the EPA cycle. And of course the car doesn't know if you'll be traveling 25 MPH for three hours or 100 MPH for however long that lasts. So in the absence of some sort of plan, rated miles is it and just indicates the battery level.

With a destination entered into the nav the car can estimate the number of rated miles/battery percentage required to reach your destination. Not exactly a range estimate, but maybe the trip meter has something like that. I don't use it. The nav uses the last 30 miles or so of actual driving as one input to its estimate. So that should pick up all the tire inefficiencies and other non-ideal conditions. That's been pretty close for us. Where it falls flat is if it starts to rain or something and the next 30 miles look nothing like the last 30 miles. Presumably the nav would use your stated wheel size to get a better travel estimate before adding the adjustment from the last 30 miles. But it might also just be to calibrate the traction control a little better.

 

[Oyinko]

I'm talking about the estimate shared by the Nav system. I find it usefully because when charging at a supercharger, I usually input my next destination and leave when I feel comfortable with the estimated SOC when reaching my destination. Last weekend, I was at Rocklin Supercharged and left with an estimated SOC of 20% to reach Truckee. However, within the first 15 minutes of normal driving, the estimation dropped to 15% which was a bit curious since I did not even started to climb up.

The same thing happened when I left Truckee and inputed Sacramento as my next destination. Estimation was 63% SOC at destination and within 15 minutes the estimation dropped to 53% even though I was driving normally.

In your message, you mention that the nav uses the last 30 miles or so of actual driving as one input to its estimate. Do you have the source for this?

It also makes sense that it uses the wheel size but there will be a lot of variance between a 18'' summer tires eco friendly and a winter tire. Hence my question about what kind of data they are using regarding tire.

 

[lbowroom]

I believe the car merely senses new TPMS sensors. It asked you which wheel package it is so it can assign a drag coefficient. Since you’re using an aftermarket tire it doesn’t match any of the OEM configurations. If your new tire is sticky it would’ve been a closer match to select the 20 inch wheels. Remember all of the rolling diameters are the same.

 

[animorph]

I've had the charge at destination jump +5% too, so it's not always bad news at least. I don't have a good explanation for that (+ or -), but it has been infrequent for me. I assume it's some algorithm reconciling current consumption and past consumption. My X, which is where most of my experience is from, is dead stock. Generally we arrive with pretty close to the expected charge level.

Sorry, no link on energy estimation. That's one of those oft repeated things and the source is lost to me. The in-car trip energy graph shows various averaged consumptions, including 30 miles, so it is something the car monitors. And when hitting rain the charge remaining slowly declines over many miles rather than suddenly stepping down. That argues for an average rather than instantaneous consumption input.

 

[Oyinko]

Understood. I did drive 45 miles on the freeway today in ideal conditions, no ac, no wind and temperatures around 66°F. I averaged 220Wh/mile with the tires... So I guess the estimation was off during my drive to Tahoe because of cold temperature and/or fully loaded car.

 

[Superspectral]

Hi!

I drive a Model 3 performance and recently swapped my 20'' wheels for a set of 18" TST Flow Forged Tesla Wheel mounted with Goodyear Assurance WeatherReady tires.

When I did swap the wheels, the computer detected new tires and I selected 18'' as the new tire size.

Since then, I find the range prediction a bit off compared to when I was running my 20" whees. I guess it makes sense because Tesla doesn't have any data on rolling resistance of the 18" TST Flow Forged Tesla Wheel mounted with Goodyear Assurance WeatherReady tires.

However, I'm wondering what kind of data they are currently using to estimate the real range of my car?

With the 18" TST Flow Forged Tesla Wheel mounted with Goodyear Assurance WeatherReady tires, I average 275 wh/mile at 65mph.

Are you getting an improvement in range with the 18 inch wheels?

Is the ride quality better than the 20 inch wheels?

Is the road noise better than the 20 inch wheels?

 

[DDotJ]

Are you getting an improvement in range with the 18 inch wheels?

Is the ride quality better than the 20 inch wheels?

Is the road noise better than the 20 inch wheels?

I'm thinking about doing the same thing. I bent two of my rims on a pothole, and they're about $700 each. Figured I could get 4 18 inch rims for basically the same price. Debating between the TSportline 18 or 19 inch rims.

I have another Model 3 w/ 18" and Aeros and it gets about 240 wh/mi vs 300 wh/mi on my Performance Model 3.

Does the vehicle handle any differently with 18" tires? Also was there a specific reason you didn't go with the OEM Michelin Primacy MXM4 tires for the 18 inch wheels?

 

[coleAK]

Understood. I did drive 45 miles on the freeway today in ideal conditions, no ac, no wind and temperatures around 66°F. I averaged 220Wh/mile with the tires... So I guess the estimation was off during my drive to Tahoe because of cold temperature and/or fully loaded car.

If you went to Tahoe from the CA side going up hill adds a lot of increased consumption that isn’t all gained on the way back down. I’m seeing 20-25% more Wh/mi when driving in the mountains vs flat.

 

[Oyinko]

I'm thinking about doing the same thing. I bent two of my rims on a pothole, and they're about $700 each. Figured I could get 4 18 inch rims for basically the same price. Debating between the TSportline 18 or 19 inch rims.

I have another Model 3 w/ 18" and Aeros and it gets about 240 wh/mi vs 300 wh/mi on my Performance Model 3.

Does the vehicle handle any differently with 18" tires? Also was there a specific reason you didn't go with the OEM Michelin Primacy MXM4 tires for the 18 inch wheels?

I did buy another set of tires and rims for the winter. While I live in San Francisco, I usually drive to Lake Tahoe a couple of times during the winter season and I wanted to be able to go there with my Model 3 instead of renting a AWD.

I bought a set of 18'' TST wheels mounted with the Goodyear Weather Ready. I choose these tires because they have much better performance on snow than the Michelin Primacy MXM4. The Goodyear have a "winter" thread at the center of the tire and are rated with the 3-peak snowflake.

I don't know about the Michelin Primacy MXM4 but I've been on the snow with AWD with M+S tires and they were pretty much useless. I did not want to take the risk to be stuck on the road or even worst.

In term of efficiency, they are much better than the 20'' as I managed to reach 220Wh/mile over 45 miles on the freeway. The tires are also much more comfortable than the 20'' and seem to be similar in term of road noise.

However, they are not good enough to handle the power of the Performance. When I floor the throttle, I feel that the wheels are spinning a bit. Having said that, since I will drive them only a couple of months per year, I don't really mind.

 

[edittman1]

How are you guys fitting 18" wheels on the Performance model? I thought the calipers were too big and prevented 18" wheels from fitting?

 

[StealthP3D]

How are you guys fitting 18" wheels on the Performance model? I thought the calipers were too big and prevented 18" wheels from fitting?

It depends upon the 18" wheel. Aftermarket 18" wheels are available to fit the Performance caliper. If I was going this route I would try to find a wheel that was a bolt-on fit without needing spacers or adapters. Going to a 19" wheel will widen the available choices.

 

[Oyinko]

How are you guys fitting 18" wheels on the Performance model? I thought the calipers were too big and prevented 18" wheels from fitting?

The TST 18'' are designed to fit the performance model. There is 3mm clearance at the lowest spot though.

 

[Kenz]

I'm thinking about doing the same thing. I bent two of my rims on a pothole, and they're about $700 each. Figured I could get 4 18 inch rims for basically the same price. Debating between the TSportline 18 or 19 inch rims.

Seems like the low profile 20" tires offer little protection for the rims against pot holes and rim / curb rash incidents.
Another issue is that the 20" "summer performance" tires are not to be driven in temperatures under 20 F. It voids the tire warranty.
I wish Tesla had an option for "all weather" bigger profile tires for the 20" rims when ordering.
Sure seems like the service center is doing a lot of 20' rim repairs and swaps that could be avoided with a wider bigger profile tire.