Interesting. You mentioned racing too. Does this mean losing rubbing from spinning tires, or merely from acceleration, as when drivers do “jack rabbit starts”?
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There are two types of friction at work: rolling friction and kinetic friction. Kinetic friction is the more salient friction in terms of causing tire wear, and it is caused primarily when the acceleration, braking or cornering of the vehicle causes the tires to slide against the road surface while rolling (this sliding also occurs when a vehicle is moving straight at a constant speed for a reason that I will discuss below).
There is one other important factor behind tire wear: deformation. Because tires are made out of rubber, they deform as they are rolling, and the process of deforming over and over again causes breakdown of the rubber material at the molecular level while also impeding perfect rolling and causing sliding even in the absence of acceleration, braking or cornering.
The load applied to the tires from the vehicle is a critical factor behind both the force involved in kinetic friction and tire deformation, and that is why (all other things being equal) tires tend to wear out faster when mounted on heavier vehicles.
I’m really bummed out. Looking at vehicles of a comparable size to the one I have now, the EV versions are 1000-1500 lbs more.
I really have to rethink my electric options; I don’t feel like I’m contributing much by trading in for a car that’s so heavy it needs a 200+ hp engine to compensate. (and 200 is on the lower edge of most of the EVs I’ve seen).
Have you considered plug-in hybrids like the Prius Prime? They have modest-sized, reasonably light batteries that allow you to operate as an EV most of the time, but have the gasoline engine (really just used as a generator) for the longer trips. There’s been analysis showing that they’re some of the cleanest vehicles you can buy, beating out a lot of “pure” EVs:
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It just seems inelegant to tote around two fuel systems and two types of motor. And the issue I have with that article is that those aren’t apple-to-apple comparisons in terms of mass, acceleration, and size. Admittedly, that’s tough, due to the fundamental difference between ICE, hybrid, and EV vehicles.
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More inelegant than manufacturing and toting around an expensive battery that’s 4X larger than what’s needed on most days?
A Prius Prime weighs 3500 lbs, about 500 lbs more than a standard Corolla and 500 lbs less than a Tesla Model 3. But with a 0-60 time of 6.5 seconds it gets better acceleration than the Corolla and is significantly faster than an old Miata or most BMWs were 20 years ago. Performance-wise, there’s nothing to complain about, especially compared to ICE vehicles that aren’t sportscars. It’s also reasonably priced at about $33k (the median car price in the US is $48k right now) so it sure seems to me like it would meet the needs of a big chunk of potential car owners.
As an engineer I do kind of sympathize philosophically with the idea that combining gas and electric is an unnecessarily complex solution with more potential failure points than either system on its own, but at this point Toyota has a lot of experience in this area, and Prius’ are generally quite reliable. Results are results.
Edit to add: turns out that the Prius Prime 0-60 time is about a second faster that Magnum P.I.'s Ferrari 308 GTS:
Crazy times, right?
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It may seem inelegant, but it’s really practical for the average commute today. While EV availibilty and infrastructure is still building they are a good transition option.
My PHEV (Mitsubishi Oulander) is my main commuter. The battery means I get to drive to and from work primarily on electricity (I average about 2000 km per tank of gas in regular use, including shuffling the kids around on weekends. Down to about 1500km in the colder snowy winter months).
But I don’t have to rely on imperfect charging infrastructure for longer trips. And it’s not that much heavier than a gas compact AWD SUV because I only carry enough battery for my average drive. And I can use cheap and easy to install slow chargers (I use a normal 120v plug at work).
So I save a massive amount of fuel, maintain more flexibility and I didn’t have to wait 3+ years on a wait list. Next I’ll get another full EV, but I am hoping the waitlists get shorter (I dont want a tesla, or the 4 years I was just recently quoted on a new KIA)
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Which is itself a good point; we’re in the infancy of EVs and hybrids have a couple decades head start in development. EVs still essentially use laptop batteries. The next steps in their progression involve higher energy density in lighter packages. The rest of the drivetrain is already lighter, even for AWD EVs that have 2 or even 4 motors.
I feel that vehicle weight is simply the latest Fossil Fuel Trollbot attack point against EVs.
Roads that are built to carry 40 ton lorries aren’t going to worry about 1.5 to 2 ton EVs, especially when 40% of conventional ICE cars weigh more than that anyway because they’re X-Box hueg SUVs.
If you’re worried about tyre wear, think of the compensating savings on fuel costs. My Renault Zoe gets 300 mpg based on electric versus petrol prices. That’s about 6 times more than a similar sized ICE car can do.
95% of car trips in the US are up to 30 miles, so a plug-in hybrid or a light battery EV with a short range is going to be fine nearly all the time.
I find the 200 mile range of the Zoe adequate even for the one or two really long trips I do per year. Last year I drove to the Lake District, over 200 miles, and stopped twice on the way for rest breaks, during which the car got charged.
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Not just acceleration, but the incredible braking and cornering forces on the tires wear them quickly. You can see it on a racetrack if you look at the surface - in the “braking zones” where cars are usually slowing rapidly and in the corners you will see a track of rubber that’s embedded in the asphalt or concrete racing surface. And if a track has predominantly right hand turns then the left side tires will be more severely worn than the right side tires due to the increase in forces and thus wear on the outside tires. Of course, that supports the “heavier weight wears them faster” claim as that also increases the forces. It all plays together I guess!
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Plus, the new Prius is actually a nice looking car, which is… Something of a break from tradition considering its unprepossessing predecessors.
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I mean, it’s social science. As an EV user I think I have the right/expectation to a tyre made from CO2 condensation reactions via various biocompatible species so that it doesn’t choke and kill so much in breakdown. But also that I don’t have to trim its nails or put booties on it in winder so it doesn’t chafe the pads?
Only of course the faring’s plastic to make up for some of it, and OFC is not some biodegradable formulation (either.)
Huh, haven’t tried to lift the car much.
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