Comments by "Mikko Rantalainen" (@MikkoRantalainen) on "Donut" channel.

Hi, LPL sent us here.
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I think any "land speed record" doing with other propulsion methods but rotating the wheels is cheating. When you put a turbojet or scramjet engine (or both!) into the thing, it turns to very low altitude aircraft and we have to start discussing when it's considered a car or airplane.
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TL;DR: Unless you're doing drag racing only, more power is not the only thing that matters.
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When are you guys going to publish the research paper? And where?
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If I remember correctly, rubber also has shear strength which means that for a given sideways force there's optimal weight per cm² where the rubber can handle the sideways load without tearing. Cases where using wider tires improves performance are usually the cases where the surface of narrower tire is sheared away due exceeding structural integrity of the rubber.
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Hydraulic brakes are only safe because they're redundant in all cars. If a car had fully redundant electronic brakes, I'd trust that, too. However, that would require dual power source, dual pedal sensors, dual wiring and dual actuators. For backup power source, having power source at the wheel hub generator and brakes applied automatically if connection to the controller in car is lost. That would be practically electronic alternative to air brakes used in trucks. I'd guess we have something like that around 2030. The technology could be ready faster but cars are so heavily regulated around the world that no manufacturer is going sell a car that is not legal everywhere.
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TL;DR: FIA politics. Year 2005 rules prevented tyre changing during the race and cars were fast and tyres lasted full race just fine. It's not that "we cannot create better tyres" but "FIA wants artificially bad tyres because they think it makes the racing more interesting". I hope that someday FIA gets a grip (pun intended) and requires e.g. minimum 1 complete tire set change during the race but allow tire manufacturers to create the best tires possible. If you want to add tricks to make things more interesting, disallow tyre preheating so that cars have cold tyres after every tyre change. Regulate the cold temperature if needed.
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Nowadays Kalle Rovanperä is the youngest World Rally Championship Drivers title winner ever. Colin McRae hold the record for 27 years.
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8:46 Who would have have guessed that bolt extractor is good for extracting bolts?
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It would have been interesting to know much much load cell + GPS tracking measured. I would assume that's the more accurate method for pulling.
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I wish some manufacturer included maintenance in their design. Pretty much all new cars have really hard time to replace alternator, clutch, suspension arms or some other wear items that's not replaced as often as brake pads. I'm fine with non-wear items being hard to replace but all wear parts should be easily replaceable. That would help both DIY people and reduce fees for paid maintance jobs.
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Sorry, I have to press the dislike button on this one due the lack facts even though your video production is otherwise nice. You are missing three huge elephants in the room for Hydrogen cars: (1) The efficiency for electricity -> hydrogen -> fuel cell -> electricity is much worse than electricity -> li-ion battery -> electricity which is used in pure electrical vehicles. When you have reneweable electricity source, it makes much more sense to load li-ion batteries than waste lots of energy on electricity -> hydrogen conversion because that produces lots of heat as waste. (2) The fuel tanks for hydrogen are both prohibitively expensive and weight way too much. Hydrogen also cannot be compressed very much. One liter of gasoline contains more hydrogen than 1L of pure hydrogen as a liquid in the hydrogen tank. And the gasoline also has lots of carbon in addition on that same volume. (3) Hydrogen economy would require A LOT more hydrogen stations to make any sense. However, there's no sense to invest to build any new hydrogen stations because issues 1 and 2 on this list. The only exception is local politics which may dump enough money to build the stations even though there will not be any customers in the long run. Elon Musk is right on this one even though he fails to clearly explain why. TL;DR: Hydrogen cars would be slightly better than gasoline or diesel cars. However, hydrogen cars are MUCH worse than pure electronic cars which is why there's no sense to build any hydrogen cars.
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Honestly, Ford wouldn't need to buy Aston Martin to copy the looks. Design patents and design rights are short lived enough that you can just copy the looks as long as you don't copy the trademarks (logos and names). If your car sales depends on the looks and the car is otherwise too crappy or too expensive, you've big problems with your business plan.
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Make sure to check the head for internal cracks. Older VAG TDI engines are well known for cracking the internals of the aluminium head when you overheat the engine even a little bit. The engine block is heavy duty cast iron and never breaks. Typically the coolant water starts to leak to intake or exhaust side of the valves.
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I have heard the explanation that 1 hp is the power that a horse can do for full day long. Big D was good for 5 pulls only and could do 5.7 hp.
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@PhaunDubstep Weight on tire is not constant. When you take a sharp corner with a car the outside tires handle way more weight hand the inside tires. If the car is decelerated or accelerated at the same time (common in racing) there will be weight difference between front and rear, too. Then there're dynamic forces, too. When the weight distribution between the forces transferred via springs, suspension dampers and anti-rollbars all have some force transfer delays which separate the weight of the vehicle from the weight applied on tires for short periods of time. For optimal performance you would want enough weight to press the thread compound into the surface roughness but small enough weight to not exceed the shear strength. And keeping the weight on that (often pretty narrow) range is very hard with the dynamic weight distribution going all around during racing. Good computer simulations such as BeamNG, iRacing and rFactor all consider these dynamic forces and I think all of those also include tire deformation, too.
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@jonathangaray7794 In my experience "wheel" in context of cars can mean just the rim, the combination of tire + rim or the steering wheel. You just have to guess from the context which interpretation should be used for each content.
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@Michael Peck Are you sure about that? I would expect car to be both suspended from the top of the tire and supported from the bottom, too. The exact ratio changes according to air pressure and rotational speed of the tire. For example, see how top fuel dragster tires deform during the acceleration.
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@Michael Peck I agree that the wheel is partially suspended from the top of the wheel. However, imagine following though experiement: take a normal car tire with a rim. Cut the top half of the tire totally away. Does the rim drop down to ground? Absolutely not, the tire has mechanical structure, too. Is the suspension power reduced? Absolutely yes. Of course, the tire design makes a huge difference on the mechanical structure. WRC rally cars use tires with so strong sidewalls that they can keep driving even with deflated tires. In tat case, the traction is heavily reduced but not zero.
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@Michael Peck Umm... what? If you cut the tire half (removing everything above the axle) the air pressure difference between the "inside" of the wheel and above the wheel is literally zero (or technically about 1 Pa if you measure about 30 cm above the cut because that's the pressure difference in atmosphere per height). I agree that different tires have very different sidewall strength. If you include bicycle tires, the lightweight tires are really really thin and flexible.
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The people that know that Toyota owns Lexus is not the market segment Lexus is going after. If you do research before committing into a purchase of an expensive item (e.g. a car), you are not going to get Lexus.
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