A handy spreadsheet for comparing tires and range

[jackmott]

The topic of efficiency and wheels and tires come up a lot. I've put together a spreadsheet that runs the numbers on these things. With it you can compare the effect of different tires, and changes in mass for steady state driving pretty well. There are some estimates here like the frontal area of the model 3, and the drivetrain losses. If anyone has more accurate figures for those let me know. But, the numbers work out pretty well, you can reproduce the differences in range between the various wheel/tire packages Tesla offers.

A second worksheet has a setup for comparing the effect of changing wheel mass for whatever acceleration scenario you want.

You should be able to make a copy that you can then edit and play with. Open to suggestions on improving this.

Vehicle Energy Maths

Highway Range From Wheel/Tire Changes Original Car Mass (lbs),4200 Battery Capacity (kWh),82 Cruising Speed (mph),70 Cd,0.23 Frontal Area,2.22 Starting Wheel/Tire Package,Modified Wheel Tire Package Wheel/Tire Weight (lbs),100,80 Tire CRR in (kg/t),7,7 Range (miles),301.7286608,302.2162577 Vehic...

docs.google.com

 

[DayTrippin]

I think for the vast majority of users, it will be too complex. At a minimum I would color code the values that people might want to edit. For example D2 and F2. I would reduce the number of significant digits displayed unless absolutely necessary such as in CRR.

I would also think about have an option to change units from metric depending on the country people are coming from. A lot of the cells could be hidden in general. If using percent, then format the cell accordingly. Such as instead of .05, format the field to show 5.00% in cell B15.

There is a lot going on there and maybe too overwhelming for people without an engineering/physics background. Just some initial feedback.

I appreciate the effort you put in it.

 

[jackmott]

yeah maybe an easy mode front end is a good idea

 

[jackmott]

Spreadsheet has been updated with easy mode, and freedom units.

 

[3sr+buyer]

Where to find CRR of specific tire models?

 

[DayTrippin]

That is the challenge. At best from what I can see is you'd have to guess somewhat. On the Euro tire sites they do give you relative efficiency ratings but no clear metrics around them.

 

[jackmott]

Where to find CRR of specific tire models?

I put little info tips if you hover on the cell in the spreadsheet. Tyre reviews, tests and ratings - Tyre Reviews and Tests has a lot of good data. The EU ratings you can probably guesstimate something like: (just based on spot checking a few tires)

A: 7
B: 7.5
C: 8
D: 9
E: 10

 

[DayTrippin]

I have also found this site is useful for showing relative ratings IF they have the tire in the system. Here is a sample output of a tire I was considering for my Model S.

https://www.tyrelabelling.eu/EU/2020-740/en/381355_fcs_en.pdf

 

[jackmott]

I have also found this site is useful for showing relative ratings IF they have the tire in the system. Here is a sample output of a tire I was considering for my Model S.

https://www.tyrelabelling.eu/EU/2020-740/en/381355_fcs_en.pdf

When I try to go to the root url, I get an error.

 

[DayTrippin]

I don't remember how I originally found it. Here is another interesting site regarding tire efficiency.

Tyres

Product Energy Efficiency - tyres. Tyres are very sophisticated products where safety, efficiency and other environmental performance parameters have to be duly balanced. They ensure comfort, acting as shock absorbers, and safety, by providing grip for braking, accelerating, maintaining steering...

ec.europa.eu