[Wimberley51]

As a newcomer to the EV world, there are so many things I am looking forward to discovering. During my 50+ year experience with ICE's, I have always been interested in the relationship between highway cruising speed, gearing, and fuel consumption. I am now starting to focus on the availability and location of charging stations, and am wondering if, in the absence of a transmission and differential, there is an optimal cruising speed in an EV. Or, is there simply a straight line ratio of speed to energy consumption. Any thoughts?

 

[timesinks]

The force of drag from wind resistance increases with the square of your velocity -- it is not linear, ICE or EV. Even the 10mph going from 55mph to 65mph can have an astonishing effect on your range in either vehicle type. And that ding in your range will pale in comparison to the ding from 65mph to 75mph. Below 45mph, the other sources of drag and inefficiencies tend to outweigh the effect of wind resistance, so it's less of a consideration.

 

[Wimberley51]

Great response and info, thank you. My F-150 gives me real time feedback regarding energy consumption (mpg), allowing me to optimize my range / economy. Do we know if there is equivalent Rivian feedback regarding consumption / range? m/KwH?

 

[EyeOnRivian]

Do we know if there is equivalent Rivian feedback regarding consumption / range? m/KwH?

If by "we" you mean members of this forum, the simple answer is no. Rivian has not released that level of information yet assuming they even will prior to production launch. So unless a member here works for Rivian (they are basically in read-only mode) any other response here would be pure conjecture at this point. Hopefully we will find out more, as customer service has promised, over the next few months and certainly before any orders need to be finalized and committed (e.g. additional and nonrefundable deposits).

Even though I wouldn't expect Rivian to provide this info if asked, I would still encourage you to ask them directly. Two reasons. First, you never know what they might say. They may surprise you/us will some info. And second, by asking it tells them as a (potential) customer this is important information and/or feature to you.

 

[Wimberley51]

By "we" you mean members of this forum, the simple answer is no. Rivian has not released that level of information yet assuming they even will prior to production launch. So unless a member here works for Rivian (they are basically in read-only mode) any other response here would be pure conjecture at this point. Hopefully we will find out more, as customer service has promised, over the next few months and certainly before any orders need to be finalized and committed (e.g. additional and nonrefundable deposits).

Even though I wouldn't expect Rivian to provide this info asked, I would still encourage you to ask them directly. Two reasons. First, you never what they may say. They may surprise you/us will some info. And second, by asking it tells them as a (potential) customer this is important information and/or feature to you.

Good idea. I will email customer service in the morning; they have provided reasonable responses to my previous inquiries. Thanks...

 

[azbill]

EVs are not geared, exception the Taycan, so the faster you go the less range you will have. That is just the simple facts, rolling friction is constant, but as @timesinks stated, drag is proportional to the square of speed. ICE vehicles have overdrive and most of those get best MPG around 45-50mph, because drag remains low and they are already in overdrive gear.

 

[eHauler]

Can't wait for when real world range numbers pour in. Anyone know what we can expect?

 

[Wimberley51]

UPDATE:

CUSTOMER SERVICE TELLS ME:

"Thanks for reaching out to Rivian and for being a preorder holder! We are excited to share all the different capabilities of the in-dash touch-screen in the coming months—stay tuned! Feel free to reach out if you have any additional questions."

GUESS WE WILL HAVE TO WAIT A LITTLE LONGER...

 

[DSK_SOBU]

I have had a Tesla S since 2013, so I can share a little bit about the range perspective and cruising speeds from that perspective. Firstly, I will note that I never cared about rolling resistance of tires before have an EV and it does make a huge impact on watts/mile at all speeds, but particularly as you go over >65mph. On relatively level ground at 70mph, my Tesla S draws about 330 watts / mile (so each KhW delivers approx 3 miles of range). That efficiency goes down significantly >75 and at >80mph, I would be drawing at 450 watts / mile, drastically reducing range. You should have very good efficiency at 65 to 70 mph. I think they are proving the KhW necessary to have 300 miles range at 65mph on the standard battery pack. I think the standard battery back is going to be 130KhW, which means that if you maintain approx 425 watts/mile (their on board computer will show you efficiency), you would have that 300 miles of range. We can assume the R1T and R1S will have more drag than the Tesla Model S, but I would be surprised if either consumed close to 425watts/mile on general highway driving compared to the Tesla S, so I think Rivian might be hedging more battery pack great load capacity, light towing, increased drag, terrain (including more climb). Hope this helps.

 

[jmbach]

My BMW i3 gets better mileage around town than on the highway, which is the opposite of what I see with my diesel Grand Cherokee (or any other ICE cars I've had). No reason to believe it'll be any different with the RIvian. Going along with what others said, the faster you go (on the highway) the more aerodynamic drag impacts range.

 

[Cactus]

I've had a Model S since 2014. R1S on pre-order. I've always wondered: What if EVs did have a second gear? Would the electric motors not need to use as much power? How would that affect range? I know Rivian has one motor per wheel, but could they gear the front motors higher for highway and the back motors lower for torque? I'm not an engineer. Hope the question is not stupid.

 

[StillCrazy]

I have had reservations on both the R1S and R1T since they were announced, however never owned an EV before last month. Since the Rivian's were delayed I purchased a Tesla Model 3 Long Range in the meantime. The Model 3 LR shows a 344 mile range when fully charged. This "range" is all smoke and mirrors for a couple reasons:
1. Most people concerned with Range are looking at how far the vehicle can travel for road trips...ie on the highway. In FL where the speed limit is 70mph, my brand new Tesla Model 3 LR will only get about 180 miles of highway driving on a full charge. This is a far cry from 344 miles of range and not something I ever see advertised anywhere.
2. If the EV's can get this "range" driving stop and go in town at 45mph...who cares??? In town driving means you can charge at home each night if needed and most people aren't driving 300+ miles around town in a day.

In my opinion, EV's should be required to post expected Range in City and Highway, just like the gasoline vehicles. I am completely rethinking my strategy of getting two Rivian's based on my experience with the garbage highway range of the Tesla and am absolutely not buying one with less than the advertised 400+ mile range. I would love to know the expected range of the "300+" mile range of the launch editions on the Highway at 65-70mph. I would be shocked if it is more than 200 miles. Hard to swallow that for trips when new SUV's like the Expedition can go 500+ miles on a tank...on the highway where it matters.