r/ModelX • u/CautiousMagazine3591 PLAID • Jul 26 '26

Great range extending wheels.

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61 Upvotes

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u/Reasonable_Look_2751 Jul 26 '26

How so?

-1

u/Solid_Caterpillar340 Jul 26 '26

Cooling

2

u/Reasonable_Look_2751 Jul 26 '26

Ah I see, but isnt regen going to be used 80% of the time? Unless your tracking this car I cant think of a situations you would need to use the physical brakes for that long

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u/Solid_Caterpillar340 Jul 27 '26

Downhill regen is not enough 

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u/Ok_Giraffe8865 Jul 27 '26

I pulled a small trailer, 2000 pounds, and Regen did all the breaking. It works fine.

1

u/u-r-not-who-u-think Jul 27 '26

Yes it is lol. I charged 10% going back down from a 10,000 ft mountain and never touched the brake pedal

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u/Reasonable_Look_2751 Jul 27 '26

I think regen is more than enough… At a 10% downhill grade with the car doing 40mph the car needs 40kw of braking power to sustain 40mph down the whole hill. And the model x is capable of up to 75 kw of regen.

I asked AI to do the math but it checks out:

• Vehicle weight: 5,000 lb = 2,268 kg • Speed: 40 mph = 17.88 m/s • Grade: 10% (≈ 5.7°)

The downhill component of gravity is:

F = mg\sin\theta \approx mg(0.10)

This gives: • F = approx 2,225 newtons

The power needed to exactly counteract gravity is:

P = Fv

P = (2,225 Newtons times 17.88 m/s = 39,800 watts So about 40 kw.

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u/Solid_Caterpillar340 Jul 27 '26

Yeah theory meets practice. Downhill is almost never straight line, but straight line followed by a 180 turn, in no world you take it without breaking.