The “R” pictured stands for “Radial.” Most tires used on production passenger vehicles today are radial tires as opposed to “bias ply” or other construction techniques. That is just referring to how the tire is made. A steel belted radial has metal “cords” inside the tire under the rubber, they impart multiple beneficial properties on the way the tires function and on their overall safety.

Most people just drive. They know little to nothing about cars and don’t generally want to. They often know little to nothing about physics or engineering- and even those who know these things often don’t think of cars in terms of how their behaviors are influenced or examples of certain principals. It’s good to know some things about... well... anything really. But especially with machines you operate. But... most people don’t have the interest or ability to absorb all the information they need to operate and maintain a vehicle with a functional understanding. That’s why for most people, it’s best to go with a competent mechanic and just stick to whatever the engineers who made the car say you should.

Tires are very complex. There is ALOT I’m leaving out. The engineering of tires and the physics involved are complex. It is often difficult to give a primer on tires that is both in depth and brief enough to serve as a tutorial people can remember.

This allows the tire to also contort and conform to shapes as it is smashed into every rock and road dimple by your 4,000lb car. Every pot hole is like dropping thousands of lbs on your tire. If tires couldn’t contort like this- not only would your ride be pretty tough for you- it would be rough on your car. Bolts and such being shaken and battered, metal being fatigued- and your poor wheels- usually steel, aluminum, or other alloys- you’d be quickly and easily bent or cracked (easier than they are with air.) not safe and not cheap replacing those regularly. But your side walls- not only can wrong pressure cause the tire bead (where the tire is held to the wheel) to come off- too low and your side walls can flex enough that the tire can rub on itself and effectively destroy itself, or the heat can cause the materials to lose their ability to do their job. Etc etc. too much and your side walls may not be able to flex enough and the tire, wheels, and your cat can be damaged.

More over- the reason we use air in tires- one of the main reasons- is pneumatic cushion. Not only does a tire with air in it generally have a higher load capability than a solid tire- it will almost always offer a better ride quality. The air can move and compress and expand far easier than most solid compounds which are suitable for making a traditional airless tire.

Tire sidewalls. You can find neat videos of high speed camera footage of tire sidewalls at work. The side wall of a tire is a complex piece of engineering and you rarely if ever notice- but it is constantly flexing in all manner of ways and directions. I won’t get into skip angles and the math of how it is possible for a car with 4 wheels to turn. But the sidewalls are a large part of why that is possible. Your vehicles handling and basic function depend on the sidewalls and their ability to flex to some degree.

Now- contact patch is effected by tire pressure. More pressure usually means a smaller contact patch and less means a larger patch. Counter intuitively- sometimes a smaller contact patch is better for traction such as in some cases with mud or snow etc. smaller contact patch means less rolling resistance and generally less friction- often less heat to the tire, better fuel mileage or EV range (to a point) but it can also decrease the vehicles ability to response to inputs including braking on dry relatively smooth pavement. Lower pressures can often offer more grip in most common situations, most rain conditions, dry pavement. But it isn’t exactly the contact patch that is to worry about here- even though it is very important. It’s the only part of your car that touches the road after all.

So usually you will want to have a pretty good reserve of load limit- more for vehicles like trucks and such- to deal with both passengers and cargo as well as forces of physics. Usually, at the extremes of physics is where you need your tires to be operating at their best or most reliable- and that is where a tire is most likely to fail if it any matched to the vehicle and conditions, and set up and cared for properly.

Because of this- a perfectly balanced 2000lb car at rest- where the rear weights 1,000lbs and the front weighs 1,000lbs- under extreme braking the front might weigh 1200lbs or more and the rear suddenly weighs 800lbs or less. 1200 divided by two overwhelms what our 500lb limit tires are rated for no?

Ok. Ok. So we have a car, that magically- all 4 tires at rest will always carry equal weight AND the car is balanced for all possible people and cargo you’d place in it and magically will never weigh more than 2000lbs total. So now it is ok to use the 500lb limit tires? No. Physics. When you turn, brake, speed up quickly- the cars weight is transferred. You ever felt yourself be pulled forward when a car stops quickly, or seen the front of a car “dip” when it brakes hard? Ever seen a dragster or a high powered remote control vehicle do a wheelie when the driver slams the gas? That’s the weight transfer. Same when you are pulled to the “outside” of the car or you see a car leaning in a corner. Centrifugal force and other factors are at play- but the effect is that parts of the car get lighter, and parts of the car get heavier. In hard braking, the rear gets lighter and the front gets heavier for example- hence the front of the car dips down.

Now- if you have a 2,000lb car- you may think that tires rated for 500lbs load are perfect- 2000lbs divided by 4 tires right? Wrong. Even amongst factory performance models that have not been corner weighted it is VERY uncommon a car will have perfect weight distribution front to back and side to side where each corner carries exactly 1/4 the weight. More over- a tank of gas can easily weigh over 100lbs- and just a driver is usually at least 100lbs- a 4 seat car with groceries can weigh easily 600lbs or more than the car alone weighs. And guess what? Say you have. perfectly Balanced car when full of gas etc and aren’t going to drive anyone else- that weighs 1900lbs and you weigh 100... those 500lb tires should work now right? No. Because you’re probably sitting towards the front of the car and to one side. That 100lbs won’t be divided evenly on all 4 tires.

But tires themselves are rated for a maximum load- how much weight each tire can support and function. Generally a manufacturer specified tire matches load ratings to the vehicle load and weight distribution, and manufacturer pressures are specified off of that. When you go to non OEM tires- you might have new load and speed ratings. A tire rated for 150mph will not be able to do that if it is over or under inflated because the tire pressure changes the behavior of a tire- notably, the heat the tire will see under any conditions. The same is true of load ratings.

My one nitpick would be with the contact patch comment. Tire pressure DOES have a tremendous amount to do with contact patch- one of the most important factors next to tire design- but there are numerous reasons why tire pressure is critical beyond that. For starters- air and most any gas will heat up and expand in a tire. Too high pressure or too low can cause a tire to slip off the bead- effectively dismount itself. But load and speed rating are actually the more critical factors in most people’s lives which tire pressure effects. A vehicle is rated for a certain load- including cargo, fuel and fluids, and passengers. This can usually be found on most passenger vehicles where you find the tire pressure.

Not to nitpick- captbojangles says some size words. Tire PSI should generally be set to whatever the manufacturer recommends for the specific tires the manufacturer specified for the vehicle. Since a good deal of people tend to buy tires other than original- in general a comparable tire will take the same pressure- but it’s best to check and if you don’t know.... your best bet would be to go with a trusted technicians recommendations. That said:

Now this isn’t some sort of revelation- it is well known. But yet... we continue to support these systems because of what we get out of them. YouTube abuses creators and yet... creators still fill YouTube with new ones all the time. People still watch YouTube even if they moan about all the terrible and greedy things they do. YouTube competitors come up, and perhaps someone will come along and take their place as the “household name” of online video sharing. But undoubtedly, anyone able to compete with YouTube would be terrible too. Perhaps terrible in other ways- but still terrible. Because we make our own monsters.

The truth is probably that a good number- the majority of individuals in fact, really might just put morality and codes of ethics in front of tens of thousands, hundreds of thousands, millions of dollars in personal revenue- if in a position where they had to choose between being “decent” or “fair” or letting money slip through their hands. But the fact is that not so coincidentally... a good number, the majority of individuals aren’t rich and making these sorts of high level decisions. Why, one might even say that an inherent underpinning of most dominant systems of social and economic conduct in history tend to reward the people willing to compromise ethics for power and wealth, while keeping those with these strong morals generally at the lower rungs of the ladder.

Now, one other thing that could use a mention- YouTube doesn’t have the “cost of entry” that most other avenues to fame do. Unlike Hollywood or music etc- you don’t have to make it past a “gate keeper” like agents or producers or scouts to show the world your stuff. YouTube provides creators access to a distribution network that few could dream of otherwise. So I’m not saying it is ok for YouTube or any other media company to abuse talent or take ridiculous profits from the work of others; the opportunities and such presented by the platform do have a value to them.

Thank you for a balanced and eloquent post carbontech. Personally I think YouTube is greedy and hinky- but anyone or thing as prolific and wealthy as YouTube would be- so I don’t know why people seem surprised; especially when we create our own monsters. If YouTube tries to launch a paid membership program to generate revenue- they are the devil. They put ads, the devil. People block ads and YouTube takes measures to secure income... devil. Basically every time YouTube tries a model to make money the internet is ablaze with anger to YouTube.

So on the low end it is maybe 100 hours of training total. That said- I’m going to agree that most security guards should get more training, and guards in critical positions and functions often will receive much longer training. I worked for a civilian organization with a bit of government overlap which trained its security force extensively and had very high standards for who was allowed to take that job. It would be about 6-12 months before a new security person was able to work solo unsupervised for most posts, and then they would be out at a post where they still worked as part of a team of more experienced security personnel who had more specialized tasks, and set to do their own generalized tasks independently but in coordination with the team.

And even then one is balancing the risk of an actual problem occurring and the chances that problem would be detected. So there are many (again, MANY, not most of all) security job posts where one can sleep or play video games or even perhaps “cut out” with the only dangers they’d ever be discovered being a chance visit by a supervisor or an actual incident happening which they would be expected to have not been able to miss if they had been performing their job to the letter or in any basically functional capacity.

It somewhat depends. But in many states, before you can become a guard you need a guard card, this varies but is often 40-60 hours of training to be certified. Many security guard positions are... well.... at most they might involve chucking doors and windows to ensure they were locked and there are no signs of tampering. Perhaps to stand or sit in place and watch a designated area, or to perform a walking patrol or some combination. There are of course more involved security guard jobs where you monitor and ensure compliance with rules etc. but it is common that the position might not require more than a short training period to do the job to the standard the company wants- which often amounts to pretty much nothing. Like being a human sensor for an alarm system or just being there to deter the lowest level of mischief makers who might do things if a place was perceived as completely vacant.

.. of reference. There are of course certain social gathers where weightier issues are discussed, and sometimes deeper conversations do come up at parties, but generally myself and most people I know follow the classic etiquette that a party is not the place to flaunt things that have controversies attached and deep feelings that can cause trouble and frustration. It’s usually better to keep things in a place where you aren’t going to offend people or alienate those party guests who may not share your views. Liquor also tends to be served at parties, which makes any serious discussion of hot issues often ill advised. That’s my experience anyway, but to each their own.

Lol. You’re actually perhaps the 5th person on this site in memory to have made this comment over the years. And generally- I am. Or at least people seem to think I am, as I am told such and get invited to a large number of events. It is easier for me to say things in person verbally as text based communication leaves lots of room for misunderstanding and less room to correct these things in real time. You’re also missing body language and tone that can allow you to convey things verbally that require more information in writing. Parties also generally have the benefit of you knowing the crowd or at least being able to read a room. The internet, you and everyone else could be anyone and I don’t know you or anything about you, so I cannot make assumptions about your culture or what you know or anything like that. Also- I don’t know about your parties, but parties I attend rarely involve in depth discussions of complex social issues amongst strangers who don’t share certain points...

Label to apply. Call someone an “Antifa” or a communist or something and the whole thing can get derailed as they explain that their views incorporate anarcho-capitalist post Marxist secular humanist theories based on a vandergraft-Hughes proto fascist economic technocracy with corpocratic egalitarianism, or some crap. So often times all that gets shortened down and people just say: “Freaking liberal nonsense...” and personally, as you all likely know, I favor lengthier and more precise labels to try and remove confusion from the world- but as long as there are people who do not, or who can’t understand nuance or muster the attention to keep up, that itself can and often is a cause of confusion because people want all that precision but in 100 characters or less, and without having to learn or adhere to newer more precise words that allow concise but detailed communications.