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Old 11-07-2023, 02:56 PM   #101 (permalink)
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Originally Posted by freebeard View Post
This is mostly about trains, but it draws comparisons with cars:

At 10:14 there is a very interesting clip of a thin-fender era car in a wind tunnel.

Trains have drag that cars don't, like flanges squealing on the sides of the rail on corners. But car tire's tread blocks deform on corners and lift one edge. So tires performance should be different on a [industry standard 100ft] circle versus a straight track.

Oh, and he could not pull a flat car by hand. I've done so a few times, but I used a car bar.


i.ebayimg.com/images/g/B34AAOSwaB5Xqfn4/s-l500.jpg
Yes, it's a great example of why trains can't stop fast with the tiny contact patch between wheel and rail, but rolling resistance with the polished interface surfaces is minimal, and seldom hydroplane.

And how are we ceratin the person is pulling the rail car vs slowing it down?


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Old 11-07-2023, 04:48 PM   #102 (permalink)
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7000Bar means no hydroplaning,

Grease OTOH works, at least according to the movie Emperor of the North Pole.
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Old 11-07-2023, 11:32 PM   #103 (permalink)
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So why omit the area that pressure actually applies to?
I included "seldom" above btw because with 6'+? of water, hydroplaning might start to become an issue.
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Old 11-08-2023, 12:36 AM   #104 (permalink)
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One of my cars is 3 1/2" to the tow bar. 6+" of water would go over the headlights. Ask me how I know.

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Old 12-06-2023, 05:42 AM   #105 (permalink)
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Narrow tires has also other positive impact to ride quality.
https://youtu.be/akL9gE7zNVQ

What does narrower tires do to your ride quality?

I made a short video on the matter to show what can you do with your ride just by changing the wheel and tire size. There are many good options other than seen in the video if you like bigger size wheels look wise. The key here is the width of the tire if you want softer ride.

If your tire flexes more you can make your car ride softer with narrower tire. Like most people think suspension is too hard with the stock Model Y 255/45R19 tires.
Or if your ride quality is good to your liking if you bumb more pressure to your narrow tire and it will still have similar ride harshness but less rolling resistance.

Here remember that tire will have less grip if you bumb pressures up. So do your own testing what is the limit of grip you need. Its not a easy puzzle and everything impacts everything. even the smallest changes can have big impacts to your cars behaviour. Do remember that in evs the tires are not wise place to save money. buy good brand tires or ones that have got good reviews in tire tests.

Many people complain tire prices and specially with winter tires. If you put smaller size wheels and tires you can even halve your tire costs when purchasing them.
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Old 12-06-2023, 08:00 AM   #106 (permalink)
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Sorry, seems like this is just becoming an exercise in tire propaganda.
My defintion of propaganda btw:

"The intentional selective use and/or distortion of facts with the primary purpose to sway. alter, or change another's opinion or position on a subject at hand and not to widen, inform or move a discussion at hand along."

A narrower tires smaller contact patch for the same carried load usually requires higher air pressure than a tire with larger contact patch tire with less pressure. Other than sidewall/carcass construction, what is the non propaganda point here related to "50% tire energy consumption"? Ride quality is subjective, effects safety and accident avoidance little, and another topic.
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Old 12-21-2023, 01:20 AM   #107 (permalink)
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In the end from 12.40 some data on tires impact to evs aerodynamics. Rounded corners on winter tires impact whole cars drag coefficient 0.02.
http://youtu.be/1KGiVzNNW8Y?si=abV0x4A0ryLRNMaj
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Old 02-14-2024, 08:30 AM   #108 (permalink)
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More tire propaganda for me or anyone else interested:

https://www.tiretechnologyinternatio...fmc_id=8442037

"Approximately 20% to 25% of air resistance energy loss in a passenger car is related to the tires and for EVs; if air resistance and resistance are combined, about 34% to 37% of a vehicle’s energy loss is related to the tires."
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Old 02-14-2024, 08:39 AM   #109 (permalink)
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Quote:
Originally Posted by Vekke View Post
More tire propaganda for me or anyone else interested:

https://www.tiretechnologyinternatio...fmc_id=8442037

"Approximately 20% to 25% of air resistance energy loss in a passenger car is related to the tires and for EVs; if air resistance and resistance are combined, about 34% to 37% of a vehicle’s energy loss is related to the tires."
That seems a little high for my taste. I wonder if they are including the effects wheel openings have.
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Old 02-14-2024, 12:57 PM   #110 (permalink)
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That seems a little high for my taste.
But still, 2/3rds of the claim in the thread title.

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aerodynamics, drag, electric car, tires, wheels

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