Smaller Wheel Range Impact

[JD797]

I currently own a standard GT model and am wondering what sort of range increase I would see if I swapped out the 20” all seasons for 18-19” all seasons/winters. Has anyone done this yet with any significant range increase?

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[Toesin]

Bumping because I am also curious about this. I’ve seen some notional data that each inch of wheel creates 3-5% of range loss although a lot of variables will be at play. Given the difference in brake size between the GT and GTPE, an 18” wheel may not fit on GTPE either

 

[JamieGeek]

Note that the CA Rt1 trim has smaller wheels for just such a reason.

My guess (which is just that: A guess) would be 1-3% or so.

 

[JD797]

Bumping because I am also curious about this. I’ve seen some notional data that each inch of wheel creates 3-5% of range loss although a lot of variables will be at play. Given the difference in brake size between the GT and GTPE, an 18” wheel may not fit on GTPE either

My understanding is that both the GT and GTPE can fit the 19” Premium wheels, but only the regular GT can fit 18” wheels (not sure if this has been confirmed, but I do know 18s won’t fit on the GTPE).

 

[Nemy]

It won't be a significant difference. I didn't notice much change in mi/kWh going from my 18" select to 19" premium. Hard to compare directly, though, since I have an ER now. Aero wheels will probably have a bigger impact, though 20" to 18" + aero will be your best bet if range is the only thing you're after.

That said, I always downsize for winter and that also helps offset some of the loss from the increased rolling resistance.

 

[Mrn]

How is the mi/kWh data calculated? Old school is dividing the odometer ∆ by the energy used and that is based on an assumed tire diameter built into the system. It gives skewed results when changing the tire diameter. Does the Mach-e use GPS data to get actual distance traveled?

 

[Auto Motive]

Weight is a big factor. Choose 26lb wheels vs the heavier types, take excess weight in the frunk and trunk out. We had 5 fold up chairs in frunk and cruise tent in trunk that actually made a difference on a long trip. Preconditioning the battery with it plugged in for 30 minutes also added range. We hit 298 miles on our gtpe and avg 285. We are running 3.5 kWh locally at 45 mpg and at 65 mpg highway at 3.0 kWh.

 

[RickMachE]

How is the mi/kWh data calculated? Old school is dividing the odometer ∆ by the energy used and that is based on an assumed tire diameter built into the system. It gives skewed results when changing the tire diameter. Does the Mach-e use GPS data to get actual distance traveled?

No, it uses wheel revolutions. If the mounted tire diameter changes, it will be inaccurate.

 

[Mach1E]

I currently own a standard GT model and am wondering what sort of range increase I would see if I swapped out the 20” all seasons for 18-19” all seasons/winters. Has anyone done this yet with any significant range increase?

From what I’ve read, you may gain 10 miles.

What’s your goal though? Drive farther or save $$.

The drive farther thing only matters if you plan on running it down to 5% charge or less.

If not, does it matter if you finish a trip at 27% or 30% battery because of your wheels swap?

 

[JD797]

If it’s only a few miles then maybe not worth it. Mostly concerned about ski trips in the winter where it might be 150+ miles round trip.

 

[Fordmaybe]

Put smaller overall size tires on will add more miles than you actually traveled as it will make more revolutions per actual mile. It will also show you speed to be faster. it will make range look better possibly in the calculation but you will still use the same amount to go actual distance not the higher distance because the wheel rotated more time per mile.

 

[daemonic3]

No, it uses wheel revolutions. If the mounted tire diameter changes, it will be inaccurate.

Yeah, and since diameter is *almost* the same even though rim is changing, it is hard to know true impact. For OP you can check the potential inaccuracy with this calculator. I populated Premium wheels vs Route1 wheels and got 702 revolutions vs 704, which equates to 15ft of odometer/speedometer drift per mile.

https://www.wheel-size.com/calc/?wh...60-18X7ET47&fcl=2in&wcl=1.25in&scl=2in&sr=0in

For the GT wheels I think they are 245/45R20 with 8" rim width. Offset seems to be 47.5 for all trims from what I looked up. Looks like going from GT 20" to Route1 18" yields 703 revolutions to 704 for a smaller impact to the ODO/Speedo.

 

[Pushrods&Capacitors]

Another factor to consider is why the Ford ride/drive engineers specified the 20”s for the GTs. A near 5000lb EV with the GT’s HP/TQ numbers has had it’s wheel/tire combo selected carefully.

Sure, you can get some 18s or 19s with a similar or exact overall tire circumference, however, to do so requires the sidewall to get taller. All things being equal, this has the potential to dull steering responses and soften the GTs lateral response. Those are two of the GTs best handling traits.

Personally, I wouldn’t make that trade off for perhaps 10-15 extra miles of range.

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