Range Estimates Menu

[SeaGeo]

Does anyone have thoughts on the difference in efficiency between the tires for use around town? I'm thinking low speeds in the city with frequent traffic lights or stop signs. Probably 1/3 of my use is this way on very short trips in urban conditions.

The loss in range from 21s to 20s or 22s seems to be 5-10%, and this is largely aerodynamics driven. But I would guess in the city, it's more rolling resistance? Is the difference going to be comparable for this use case? Or perhaps it's negligible at low speeds?

I *suspect* you'll see a bigger delta between the three tires in town as the rolling resistance and the weight of the wheels plays a bigger roll than at speed. I also suspect that the range values that Rivian quotes are based on a typical highway speed (or similar) to start. I would guess that even at speed most of the difference between the 3 wheels is rolling resistance, but that's just a hunch.

Sponsored

 

[SANZC02]

Typically city driving does better than highway driving for an EV.

The speeds tend to be lower and you utilize regen a lot more. From my perspective the if you looked at the lower numbers in the range on the estimates for the tire differences you should be close. The upper number in those ranges probably for highway.

That is just my guess though, I am still waiting for my R1S and live in Southern California where city driving means something different than Midwest and East Coast.

 

[SANZC02]

I *suspect* you'll see a bigger delta between the three tires in town as the rolling resistance and the weight of the wheels plays a bigger roll than at speed. I also suspect that the range values that Rivian quotes are based on a typical highway speed (or similar) to start. I would guess that even at speed most of the difference between the 3 wheels is rolling resistance, but that's just a hunch.

Interesting, I’m guessing different because of increased regen in the city.

 

[SeaGeo]

Here's for the 21s. Thanks to reddit user alexmaknet.

@OutofSpecKyle think you could pull 325 miles out of the aero tires? I wonder if the max pack will be the second EV to pass the 400 mile mark in the InsideEVS 70mph range test if done on 21s...

 

[SeaGeo]

Interesting, I’m guessing different because of increased regen in the city.

I think we may be saying slightly different things.

I was saying that the difference between tires may be more (ie 290 vs 325 highway 20-->21s, and making numbers up 300 vs 350 miles city). Regen is generally something like 70% efficient typically, so the more inertial energy you have to deal with, the more energy you lose. Basically this is part of the reasoning in my mind that the R1T is more efficient at speed on the highway than the Lightning, but less efficient in town (per EPA numbers). The Rivian weighs more, so it takes more energy to overcome the inertia of sitting still. When you're cruising at 70 mph, that's mostly just aero and rolling resistance.

 

[SANZC02]

I think we may be saying slightly different things.

I was saying that the difference between tires may be more (ie 290 vs 325 highway 20-->21s, and making numbers up 300 vs 350 miles city). Regen is generally something like 70% efficient typically, so the more inertial energy you have to deal with, the more energy you lose. Basically this is part of the reasoning in my mind that the R1T is more efficient at speed on the highway than the Lightning, but less efficient in town (per EPA numbers). The Rivian weighs more, so it takes more energy to overcome the inertia of sitting still. When you're cruising at 70 mph, that's mostly just aero and rolling resistance.

I agree we are saying opposite things.

Around my house in SoCal I agree with your assessment, we do not have typical city driving as the speeds are to high and it is constant hard accelerations. This causes my miles per kw to drop but when I am in a place that is more “city” driving with moderate speeds traffic lights and stop signs I can get more miles per kw than I usually get on the highway with my Model S.

 

[SeaGeo]

I agree we are saying opposite things.

Around my house in SoCal I agree with your assessment, we do not have typical city driving as the speeds are to high and it is constant hard accelerations. This causes my miles per kw to drop but when I am in a place that is more “city” driving with moderate speeds traffic lights and stop signs I can get more miles per kw than I usually get on the highway with my Model S.

I think we're still misunderstanding each other a bit here. I agree that city driving will generally result in more range than highway driving. No disagreement there.

I was just saying I think the 20s benefit from city driving less than the 21s.

 

[SANZC02]

I think we're still misunderstanding each other a bit here. I agree that city driving will generally result in more range than highway driving. No disagreement there.

I was just saying I think the 20s benefit from city driving less than the 21s.

Ok, I see what you are saying.

If I ever get mine I will have to drive around and compare.

 

[whyasky]

I think we're still misunderstanding each other a bit here. I agree that city driving will generally result in more range than highway driving. No disagreement there.

I was just saying I think the 20s benefit from city driving less than the 21s.

Seems plausible. Until someone puts all seasons on those 20s. Then we're back to the drawing board.

 

[zefram47]

I wonder if the max pack will be the second EV to pass the 400 mile mark in the InsideEVS 70mph range test if done on 21s...

It's plausible. Using the 125 kWh Kyle saw you get 92.5% of the claimed gross pack size as usable, so the 180 kWh pack should be around 166.5 kWh usable. 325 miles on the 21s in Conserve as an estimate, where it was pretty damn close for the 20s, would get you 2.6 mi/kWh vs the 2.3 mi/kWh and change with the 20s. Apply that to the max pack and you get in the vicinity of 433 miles...but I'd also assume a little less efficiency with the larger pack on weight, but at highway speeds that should be minimal. Should also put the 20s on the max pack close to 380 miles.

Sponsored