Model 3 external dimensions and comparison data...

[X-Auto]

So I got these numbers from Model 3's Wikipedia page and drew these measurements for the Model 3, also I created a table where we can compare the external dimensions of several Sedans both mid-size and big ones to Model 3 including the wheelbase, if interested you can view the table here: Tesla Model 3 Exterior Dimensions Comparison - Data & Analysis

Model 3's long wheelbase and more width will actually enable it for a battery bigger than 75 kWh?

Please Let me know your thoughts !

 

[garsh]

Very nice.

Model 3's long wheelbase and more width will actually enable it for a battery bigger than 75 kWh?

Elon has already stated that it won't fit more than a 75.
Elon Musk on Twitter

 

[X-Auto]

Very nice.

Elon has already stated that it won't fit more than a 75.
Elon Musk on Twitter

Right, but it has a longer wheelbase compared to similar ICE vehicles, however 75 kWh is going to give good range for a smaller vehicle than the S !

 

[wdolson]

I suspect they orient the cells horizontally in the Model 3 instead of vertically to get a little more headroom inside (poor headroom for longer torso people has been a complaint with the Model S). The Model 3 pack might be close in size to the smaller Model S/X pack (the 14 module pack) in width and length, but it will be thinner in height. That may be why the Model 3 can't have more than a 75 KWh pack.

 

[R.S]

View attachment 226053

Model 3's long wheelbase and more width will actually enable it for a battery bigger than 75 kWh?

Please Let me know your thoughts !

There has already been some speculation, as to why the Model 3 can only hold 75kWh, even though it's wheelbase is so long.

The most probable answer is that in a Model 3, both motors are within the wheelbase:

While in the Model S, the bigger rear motor is behind the rear axel:

That way, the Model 3 might have less space for batteries. But I think it was intentional. They didn't find out they couldn't fit more than 75kWh, but rather engineered it in a way, that 75kWh would fit.

Because 75 kWh seems to be enough for the Model 3, at least for now.

 

[03DSG]

There has already been some speculation, as to why the Model 3 can only hold 75kWh, even though it's wheelbase is so long.

The most probable answer is that in a Model 3, both motors are within the wheelbase:

While in the Model S, the bigger rear motor is behind the rear axel:

That way, the Model 3 might have less space for batteries. But I think it was intentional. They didn't find out they couldn't fit more than 75kWh, but rather engineered it in a way, that 75kWh would fit.

Because 75 kWh seems to be enough for the Model 3, at least for now.

Great thread and great observations. The completely different placement of the rear motor on the 3 achieves some interesting effects:
- Allows for the longer wheelbase vs. the overall length.
- Allows for a shorter rear overhang.
- Increases available inner trunk space with the shorter overhang.
- Improves handling by keeping the motor in front of the axle.
= less oversteer tendancy especially on the RWD versions.

Well done Tesla

 

[Big-T]

Great thread and great observations. The completely different placement of the rear motor on the 3 achieves some interesting effects:
- Allows for the longer wheelbase vs. the overall length.
- Allows for a shorter rear overhang.
- Increases available inner trunk space with the shorter overhang.
- Improves handling by keeping the motor in front of the axle.
= less oversteer tendancy especially on the RWD versions.

Well done Tesla

I"m curious about the affects of less oversteer on RWD versions you mentioned, can you elaborate on that?

 

[azred]

View attachment 226053

So I got these numbers from Model 3's Wikipedia page and drew these measurements for the Model 3, also I created a table where we can compare the external dimensions of several Sedans both mid-size and big ones to Model 3 including the wheelbase, if interested you can view the table here: Tesla Model 3 Exterior Dimensions Comparison - Data & Analysis

Model 3's long wheelbase and more width will actually enable it for a battery bigger than 75 kWh?

Please Let me know your thoughts !

Nice chart, but Wikipedia as the data source? I only wish the chart was based on fact rather than speculation as the estimated length will barely work in my garage space currently allocated to my Model 3. I recall Motor Trend estimated the dimensions based on their photo shoot last year but obviously that photo shoot estimate wasn't anything to count on. They weren't able to measure the prototype and the dimensions of the prototype may differ from the actual car.

 

[R.S]

I"m curious about the affects of less oversteer on RWD versions you mentioned, can you elaborate on that?

To put it very simple: if you corner too quickly, the more weight behind the rear axel, the more force on the rear tires, the more likely the car will oversteer. In this case it doesn't even matter where the drive goes, but only the lateral forces on each wheel.

If the tires are the same back and front, a car with more weight in front will understeer, while a car with more weight in back will oversteer.

If the center of gravity is in the middle of both axels, you will end up with the most grip possible, with given tires. That's why supercars are usually mid engined.

Suspension, uneven tire width and so on, also has a part to play in it, but if we see those as given, the location of the center of gravity has an influence over how the car responds to cornering.

 

[JeffK]

There has already been some speculation, as to why the Model 3 can only hold 75kWh, even though it's wheelbase is so long.

The most probable answer is that in a Model 3, both motors are within the wheelbase:

View attachment 226070
View attachment 226071

While in the Model S, the bigger rear motor is behind the rear axel:
View attachment 226072
View attachment 226073
That way, the Model 3 might have less space for batteries. But I think it was intentional. They didn't find out they couldn't fit more than 75kWh, but rather engineered it in a way, that 75kWh would fit.

Because 75 kWh seems to be enough for the Model 3, at least for now.

I wonder what this means for the frunk...

 

[T34ME]

I wonder what this means for the frunk...

Good things!

 

[BluestarE3]

I wonder what this means for the frunk...

A!though it may change on the production car, this is what it looks like in the original prototype:

 

[Big-T]

To put it very simple: if you corner too quickly, the more weight behind the rear axel, the more force on the rear tires, the more likely the car will oversteer. In this case it doesn't even matter where the drive goes, but only the lateral forces on each wheel.

If the tires are the same back and front, a car with more weight in front will understeer, while a car with more weight in back will oversteer.

If the center of gravity is in the middle of both axels, you will end up with the most grip possible, with given tires. That's why supercars are usually mid engined.

Suspension, uneven tire width and so on, also has a part to play in it, but if we see those as given, the location of the center of gravity has an influence over how the car responds to cornering.

I get all that, but the OD3SG said that the different placement of the motor in the model 3 (I assume he means compared to the model S) is going to result in less over steer tendency of the Model 3 RWD compared to the model S RWD.

The thing is, most of the weight of a Tesla is already centered around the battery pack, according to Quora the electric motor on a Tesla S weighs about 70lbs. The battery however weighs in at over 1,300lbs. I was curious on how a relatively small change in placement of a 70lb motor would help out oversteer when the battery pack which is almost 20x heavier than the motor already centered in the car.

 

[R.S]

I get all that, but the OD3SG said that the different placement of the motor in the model 3 (I assume he means compared to the model S) is going to result in less over steer tendency of the Model 3 RWD compared to the model S RWD.

The thing is, most of the weight of a Tesla is already centered around the battery pack, according to Quora the electric motor on a Tesla S weighs about 70lbs. The battery however weighs in at over 1,300lbs. I was curious on how a relatively small change in placement of a 70lb motor would help out oversteer when the battery pack which is almost 20x heavier than the motor already centered in the car.

In that specific case, there is no real difference. Sure, 70 lbs is still something and the reduction gear and inverter might add up the whole weight count to well over 100lbs, but because of the big battery placed in the middle of the car, the effect on where a 70lbs motor in a Model S sits, would be irrelevant.

For the Model 3 it might be different, since the batteries should weigh less than 700lbs, even the biggest ones, but still, the Model 3 should in either case behave more like a mid engined car, than a rear engined car. The main reasons for putting the motor in front of the rear axel probably don't include handling benefits, but rather packaging and crash structure.

Side note: While it isn't really relevant to the discussion, I'd really be interested in knowing how much a motor in the Model S really weights. I know where the 70lbs number came from, but I somewhat still doubt it. Strangely no one ever put that thing on a scale, at least no one I know off.

 

[garsh]

I suspect they orient the cells horizontally in the Model 3 instead of vertically to get a little more headroom inside

The pictures of the battery pack at the reveal imply that the cells will still be vertical.

Before Elon tweeted that the max size would be 75kWh, I tried calculating what the max could be. I came up with 85kWh for vertical cells, and much less when assuming horizontal cells.

 

[McHoffa]

I get all that, but the OD3SG said that the different placement of the motor in the model 3 (I assume he means compared to the model S) is going to result in less over steer tendency of the Model 3 RWD compared to the model S RWD.

The thing is, most of the weight of a Tesla is already centered around the battery pack, according to Quora the electric motor on a Tesla S weighs about 70lbs. The battery however weighs in at over 1,300lbs. I was curious on how a relatively small change in placement of a 70lb motor would help out oversteer when the battery pack which is almost 20x heavier than the motor already centered in the car.

Have you ever carried an 80 lb bag of concrete in your trunk? It definitely affects steering to add weight back there, even in a fwd car.

 

[ecarfan]

@R.S Very perceptive! I have watched the Model 3 reveal video multiple times and never noticed that. Now that you point it out, it is clear that both motors are within the wheelbase. My guess as to why Tesla designed the car that way is so they could minimize the front and rear overhangs and maximize the internal volume, reducing the overall size of the 3 compared to the S but still ensuring that 5 adults would fit "comfortably", as Elon emphasized during his presentation. This design still provided space for a 75kWh battery pack which will likely provide a range of close to 300 miles, enough for most (not all!) people and fits nicely with the "premium" Model S which with the 100kWh pack offers significantly more range.

There has already been some speculation, as to why the Model 3 can only hold 75kWh, even though it's wheelbase is so long.

The most probable answer is that in a Model 3, both motors are within the wheelbase:

View attachment 226070

That way, the Model 3 might have less space for batteries. But I think it was intentional. They didn't find out they couldn't fit more than 75kWh, but rather engineered it in a way, that 75kWh would fit.

Because 75 kWh seems to be enough for the Model 3, at least for now.

 

[SoCalGuy]

If the cells are vertical that would imply a higher floor and less headroom, all else being equal since according to this picture from Tesla, the new cells are taller than the old ones.

 

[Big-T]

Have you ever carried an 80 lb bag of concrete in your trunk? It definitely affects steering to add weight back there, even in a fwd car.

Sorry if I'm wrong, just trying to understand the statement not to be argumentative here. - but on the RWD versions of the S and 3 will both have their motor in the back, just with the S it's a little behind the wheel base, and with the 3 it's going to be forward a bit. So we're not adding an 80lb bag of concrete we're just moving it from one edge of the trunk to the other - in something that weighs close to a base model Ford F150. Will this placement change really cause understeer to be better on the 3 vs the S?

 

[R.S]

@R.S Very perceptive! I have watched the Model 3 reveal video multiple times and never noticed that. Now that you point it out, it is clear that both motors are within the wheelbase. My guess as to why Tesla designed the car that way is so they could minimize the front and rear overhangs and maximize the internal volume, reducing the overall size of the 3 compared to the S but still ensuring that 5 adults would fit "comfortably", as Elon emphasized during his presentation. This design still provided space for a 75kWh battery pack which will likely provide a range of close to 300 miles, enough for most (not all!) people and fits nicely with the "premium" Model S which with the 100kWh pack offers significantly more range.

As to why Tesla chose 75kWh, I have multiple theories.

1) it clearly puts the Model 3 below the Model S. When we look at BMW, or Mercedes, they attach, now very made up, displacement numbers to their vehicles, to differentiate them. The same goes for kWh in a Tesla. So even the most basic Model S has at least as much kWh as any Model 3, even if it's range might be lower.

2) 75kWh should give the Model 3 more than 300 miles of range. 118MPGe combined should be enough to achieve that, which seems doable, even for a RWD Model 3 75. If there is an additional improvement in charging speed, 0-80% in 15 minutes for example, 300 miles would be very practical and additional range wouldn't really add much value, but additional costs and packaging problems.

3) If there is a higher range option, it devalues the base model's range. To give an example (and I mean example, the following numbers are totally made up and aren't up for discussion): If the base Model 3 had 230 miles of range for 35k, it seems like a nice deal to us, even if there is a 300 mile Model 3. But if there is a 400 mile Model 3, 230 doesn't really sound so nice in comparison. Some would feel they need more, just because there is the option of having more. And if the 400 mile Model 3 is too expensive, they might go for a petrol car instead.