50% of your EV energy consumption comes from wheels and tires

[redpoint5]

Just imagine the fraction of energy it will represent when we're cruising around on Mars. 100% losses on the moon.

[aerohead]

Originally Posted by Vekke

I have been cracking some numbers related to my new wheels and tires and it seems that 50% of your electric cars energy consumption comes from wheels and tires. So saving potential is huge.



It is not wise to put 255/45R19 tires to your family car if your goal is to maximize the range. I have already proven that there is easily 10% savings potential in Model Y, but more accurate estimation suggest 12-15% savings when everything is done rigth.


Some manufacturers are running wiser tire sizes than others. but there is more to this than just tire size as aerodynamics are so important. I have seen good trends like in BMW IX1 205/65R17 size when taking measurements, also 205/55R19 from goodyear used in Renault looked very aerodynamic, but those I havent yet measured.

My plan is to prove you can have good driving characteristics even with tall and narrow tires.

If one does the Road Load calculations for 'ANY' car, whether Otto-cycle, Diesel-cycle, Otto-Hybrid, Diesel-hybrid, ditto Plug-in hybrids, or BEV, they'll find that, at some thermally-equilibrated, constant-speed velocity, that the aero and R-R are equal to one another ( 50% each ).
* The 1924 Rumpler Tropenwagen Limousine's wheel addition to it's basic boat-hull body is credited with an approximate 50% drag increase by Rolf Buchheim of VW, who did the wind tunnel testing.
* The 1981 VW-Flow Body long-tail, also by Buchheim, is credited with a 53.5% drag increase over it's basic body.
* The 2012 Audi A3 Hatchback demonstrated a 47.66% drag increase with the addition of wheels.
Adding full, front and rear wheel skirts reduced the wheel drag increase to only 37.38%. Adding full-swept wheel fairings, as with the VW XL1, would reduce the balance of the wheel drag by up to 70%, according to Goro Tamai of MIT.
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* The dynamic R-R fraction varies linearly with increased velocity.
* The dynamic aero fraction of wheel drag varies geometrically, at v-squared for 'force', and v-cubed for 'power.'
* The wheel's 'windage' / 'ventilation' drag portion can be 'zero-to-3% at top speed ( 141-mph [ 227-km/h ] on the TESLA Model 3, depending on wheel cover design.