re: "Google Wallet may be making a return" (and "Why is it so complex

Of course they do.

Arlen is (as usual) utterly ignorant of reality.

Sure...

...but if you want to go down that road, so is using or even listening to the radio...

...to say nothing of talking to a passenger.

Sorry, but there are such things in this world as "reasonable limits"

So is talking to the pax and listening to the radio.

Andy Burnelli/Arlen Holder/Dean Hoffman/Nil/Robin Goodfellow/more is wrong of course™.

According to the the NHTSA, for 2019 in the U.S.:

Total fatal crashes: 33,244 Total fatalities in fatal crashes: 36,096 Fatal crashes caused by distracted driving: 2,895 (9%) Total fatalities in fatal crashes caused by distracted driving: 3,142 (9%) Number of cellphone distraction-affected fatal crashes: 387 (13%) Number of cellphone distraction-affected fatalities: 422 (13%)

So about 87% of distracted driving crashed and fatalities were caused by factors other than cell phones.

So about 1.2% of fatal crashes (9% x 13%) were caused by drivers distracted by cell phones.

The NHTSA mentions other distractions that make up the 87%, "eating and drinking, talking to people in your vehicle, fiddling with the stereo, entertainment or navigation system."

Using a phone while driving is a distraction even when it's being used hands-free.

Not sure how to address the other 87% of distracted driving fatalities, or even the portion of the 13% caused by cell phone use since even hands-free doesn't solve the distracted driving problem. Texting while driving could be addressed via technology but it would have to distinguish between drivers and passengers. In the two vehicles we have owned with built in navigation systems, you can't enter addresses when the vehicle is moving, which is a real pain when a passenger could be the one using the system. There were workarounds but they were beyond the capability of most owners.

Hi Xeno,

The problem here is that intuition is a terrible thing when it's wrong.

I don't discuss anything with Rod Speed or Alan Baker (or Jock, who is just Rod Speed by another nym, et. al), but you can comprehend basic logic.

First off, _everyone_ (including me!) would "think" that cellphones are a _sufficient_ distraction to cause accidents, and, in fact, they do.

Except....

There is zero evidence of that happening, en masse, in the "good" data, which is the US Census Bureau data from the 1920's to current on traffic accidents in each state (individually & combined) over the years.

None. zip. nada.

The _only_ place you see this supposed increase in accidents is in the bullshit data {e.g., news anecdotes, lawyer web pages, insurance company web pages and police/politician web pages}.

Now maybe lawyers and especially insurance companies know more than does the US Census Bureau of traffic accidents, but that's not likely. It's far more likely their data is skewed. So let's ignore their skewed crap at first (we can always come back to their crap when/if we need to if we want to).

If we look at the best data there is for US traffic accidents, you find zero effect from the very clear ownership information of cellphones in the US which sky rocketed in a decade and yet accident rates didn't change a blip from their general downward trend that they always had (last I checked was pre-covid days but _rates_ don't depend on miles driven so I'd expect no change from covid given cellphone ownership didn't change either).

No adult discussion is possible until you agree on that fact (which I don't expect anyone to agree with until they check for themselves). Once they do agree on that fact, then (and only then) we can progress to why.

I think I know _why_ cellphones have zero effect on the overall accident rate and the reason why I think is that people who will have accidents will _always_ have accidents (essentially because they're stupid people when it comes to driving - but let's not go there yet). (There's a reason insurance companies give discounts to intelligent people.)

The fact is that cellphones _are_ a distraction, and the fact is there are plenty of bigger and smaller distractions when driving.

I don't expect anyone to understand a word I'm saying above, mainly because people are stuck on the idea that cellphones _do_ cause accidents enough to change the rate, but the facts show that just isn't true.

Intuition is a terrible thing when it's wrong.

Anyway, I think the reason the fact is that cellphones didn't change the accident rate had nothing to do with laws (as people don't follow the law and even if they did, laws were enacted at different times in different states and the rates didn't show any change anyway)...

Nope.

The reason, I think cellphones didn't change the rates is that, instead of, oh, say, the top ten, twenty, or fifty or even a hundred distractions that "can" happen while driving, cellphones phones simply took the place of one of them, oh, say, just making this up, say it's number eight.

So what happened is the previous number 8 distraction (say that was crying babies) just moved to number 9, and the total number of distractions (say it was 100 before, changed to 101), and that's why there's no change in accident rates.

In summary, three points I make for intelligent people to discuss.

1. Intuition says they are a distraction and intuition then tells us that this added distraction should increase accident rates...
2. But fact tells us this isn't happening (and never did).
3. Therefore, if we agree with point 1 and point 2, then it behooves us to _understand_ why.

BTW, it's the _same_ wrong intuition on the warped rotors, or the intuition that if you pay more for an iPhone it _must_ be more powerful, etc.

Intuition is a terrible thing.

In the case of cellphone accidents, intuition is a terrible thing, since the good data on accident rates shows _zero_ effect of cellphone ownership.

Be careful when comprehending what I said, and not what you _think_ I said.

Rain causes accidents. A good economy causes accidents. Construction causes accidents. Hot coffee causes accidents. Crying babies cause accidents. Driving while upset causes accidents. Scratching your ass while driving causes accidents. ... (list goes on forever)...

The question to ask is where in that list of infinite things that cause accidents, is where you'd put cellphones, and, then... why didn't doing that have _any_ effect whatsoever on the accident rate?

What you want if you are a politician or a lawyer or an insurance company is to talk "accidents" (the more sensational the better).

But what you do if you are a scientist is talk accident rates.

If you want to talk accidents, then I can prove anything you want me to prove simply because I can find a bacon cheeseburger which caused an accident.

What you have to show is the _accident rate_ did "something" before, during, and after the meteoric rise in cellphone ownership percentages.

And you can't. Not without picking _only_ lawyer web sites, or insurance web sites, or political bullshit web sites (particularly from police agencies wanting more money), etc.

But try to find a _single_ USA accident rate set of reliable data that covers the time period from _before_, during, and _after_ cellphone ownership has skyrocketed that shows _any_ effect whatsoever of cellphone ownership on accident rates.

Without that data, you're just guessing. I don't know if I mentioned it yet but intuition is a terrible thing.

Bear in mind I made a mistake in what I said since it was off the cuff...

I looked back and I said "accidents" so please accept my apologies in that I meant the accident rate, as _anything_ causes accidents (even a duck waddling across the road or fiddling with the radio tuner, etc.).

I type Usenet messages off the cuff, so what I'm saying is nobody has ever found in the _reliable_ data (not cherry picked lawyer web sites!) any effect whatsoever on the accident rate before, during, and after cell phone ownership percentages skyrocketed.

Nobody can discuss why until they agree with that fact. If you disagree with that fact, all you have to do is provide the data.

But the only data you can find that meets your intuition is that from insurance companies, legal companies, and government agencies that make money of ticketing.

Surely if the accident rates did have an effect from cellphone ownership going from zero to nearly 100% in the USA, then you should see something in the accident rates, Right?

Notice may argument is very clear. The accident rate in all the reliable data shows no effect whatsoever.

The question is why.

Steve is a politician, so I simply call him out on his cherry picked bullshit above where I doubt Steve is smart enough to realize he used every bullshitter's trick in the book to make his bullshit argument above.

Remember my main point which is intuition is a terrible thing indeed. What matters are only the facts.

1. Nobody knows what distraction caused most accidents, as all those "distracted driving" statistics are bullshit (ask Steve _how_ they gather that data). HINT: I know how. Does Steve?
2. Almost _all_ accidents are caused by distracted driving, so 9% is _clearly_ cherry-picked bullshit. It's likely almost 100% (barring mechanical failures, for example or trees falling off of overpasses or someone shooting someone etc.).
3. What matters is the accident rate in the USA before, during & after the meteoric rise of cellphone ownership. HINT: I know that too. Does Steve?
4. Injuries are a second order effect so far removed from accidents that _anyone_ how resorts to 'fatalities' is _always_ a bullshitter for a huge number of reasons, not the least of which is that you can't have any injuries if the accidents don't happen and more to the point that fatalities are related to a huge number of factors, some of which cellphones actually reduce (since they speed up ambulance service, for example - as does traffic routing).

Be careful about anyone bringing fatalities into the discussion since that's a clear mark of a bullshitter if we're talking about accident rates given you can't have fatalities if you don't have the accident first.

Remember, warp (as in potato chip) is _different_ from runout. Warp will cause runout but so will a lot of other things cause runout.

Let's take those items one by one: a. wear b. distortion c. runout d. And the like

Which one of those are you considering "warp" because if you say "all of them" then you're saying everything _is_ warp, and I'm not saying that.

I'm saying warp is something very specific, and it's _not_ runout (which is something else altogether), and neither is it wear.

I don't know what you mean by "distortion" but that's the closest term you used to what is warp (as in potato chip).

Warp is checked against known a flat surface, as you're well aware, where warp, the way I'm using it, means one side (at least) of the rotor is not laying flat on the test bench (the other side may or may not be parallel as that's even worse if it's not equivalent).

We should assume solid rotors for simplicity, but I understand that common vehicular rotors often have two discs separated by fins so there are a few measurements we can make against a flat bench surface to measure warp.

Warp (as in potato chip) will certainly cause runout but runout itself isn't warp.

Runout isn't warp.

I only bring that up because morons always try to find holes in my scientifically based arguments and that's one of the holes they are desperate to find.

Runout isn't warp.

And besides, the simplest cure for what people "call" warp often is a rebedding procedure which has _zero_ effect on the bolt torque and zero effect on runout.

Warp almost never happens and anyone who says it did never mesaured it. Not even you Xeno. Nobody does (except people who _understand_ what warp is, as in potato chip).

You can't test warp on the vehicle (not reliably anyway). It has to be tested on a known flat bench (or using known flat tools).

Holy S*it. Of course. A truly warped rotor (as in potato chip) is f***ed up beyond belief. No amount of pad rebedding will solve a warped rotor (as in potato chip).

Almost nobody could machine a warped rotor (as in potato chip) back to perfection simply because the amount of metal needed isn't going to be there if the warp (as in potato chip) is appreciable.

I'm going to have to call bullshit on the warp (as in potato chip) since there is zero chance that you measured it (using the proper tools for warp, which, as you well know, requires a known straight tool).

I doubt it. Rotors are made of a variety of steels (e.g., motorcycle rotors are often stainless steel) but even for the worst quality cast iron rotors, look up the temperature it takes to melt them.

I'm not saying it's impossible. But I doubt it happens for normal passenger vehicles (I'm not talking space shuttle stuff or fighter plane stuff).

Look it up.

Yes. I know. But did you measure warp (as in potato chip)?

You can't measure warp without a known straight surface to compare against. A mic won't measure warp. A dial gauge won't measure warp (unless it's a special setup).

HINT: I've never seen anyone who did who said their rotors warped when what really happened was something else (e.g., runout or pad deposition).

I seriously doubt an actual warp (as in potato chip) could be machined, but if it's only slight, then maybe, but what fool would want rotors that were actually warped (as in potato chip) even after they were machined?

If the rotor was truly warped (as in potato chip), I would think the only feasible solution is to junk it. I'm sure some 'can' be machined to spec, but I, for one, wouldn't want that rotor on my passenger vehicle.

Did you machine stainless steel rotors?

Or mounted on a brake lathe

I wasn't saying anything about rebedding at all.

Depends on the amount of warp and whether the rotor still meets minimum specs afterwards. It only takes a very small amount of warp for the driver to be able to sense it.

The car showed *symptoms* of warp, the rotors, when measured showed

I don't, I saw the evidence.

Automotive rotors were pretty much all cast iron back in the era concerned. And the rotor did *melt* at the periphery, as I stated. It had been damn hot all over but the periphery was clearly melted.

Nor am I. I wasn't and never have been an aviation mechanic.

No need, I saw the evidence directly.

Yes, I did, with a dial indicator. Definitely warp.

It was a special setup - a brake lathe. Runout and warp shows up very clearly when the hub and rotor assembly is correctly mounted.

Depending on the site, runout can be a symptom of warp. You verify it as warp by checking both sides.

Well, these days the rule is discard and renew, don't machine. Procedures have changed.

Nope. never saw a stainless steel rotor when I was involved in brakes. All seemed to have been cast iron of varying grades. That said, I didn't work on exotic cars nor did I work on motorcycles or aircraft. YMMV.

Agreed. All you need is a long flat edge and feeler gauges as a minimum.

I'm all about facts. I'll change my mind in a split second if that's where the facts lead.

Let's look at the facts in this discussion between two adults on Usenet.

My point is that nobody who says warp (as in potato chip) measures that warp (as in potato chip), where I already know that warp (as in potato chip) isn't what happens when a brake rotor is subject to intense heating & cooling cycles. "High quality brake rotors that pass SAE J2928 Brake Rotor Thermal Cracking Procedure for Vehicles below 4,540 kg GVWR proves they don't warp"

As I said, intuition is a terrible thing indeed. "Calling it brake rotor warp demonstrates a complete misunderstanding of the metallurgy and the braking process"

OK. But the fact that rebedding works sometimes means that what it fixed wasn't warp (as in potato chip). What it fixed wasn't runout either.

What it fixed is the only thing it _could_ fix, which is deposit buildup.

Intuition is a terrible thing indeed. "The brake pads and rotors in a street vehicle can't possibly generate enough heat to warp a brake rotor."

Agreed.

However, any rotor that was subject to enough heat to truly warp it (as in potato chip) was subject to _tremendous_ heat - almost impossible to attain in a passenger vehicle (again, I'm not talking about the space shuttle here). "The heating and cooling that people refer to when discussing 'warped brake rotors' would cause cracking, not warping."

There are half a dozen materials rotors are made of though, so we'd have to look up the melting point of each of them to be more precise about melting.

1. cast iron
2. steel
3. stainless steel
4. laminated steel
5. high carbon iron (e.g., Sparta CX3.5)
6. ceramic

I'll leave it at that since I respect your experience.

Read this please, though (it's just one random hit of many of course):

All the quotes in this one post are from that reference, but I can easily find more because I know what I know and most people are intuitive.

Did I mention yet that intuition is a terrible thing?

Again, I respect your experience.

However, you have to respect my knowledge that _reliable_ sources say otherwise and that runout isn't warp (as in potato chip) and that if rebedding worked, it wasn't warp (as in potato chip) after all. "Even if you're traveling straight down the side of a mountain with your brakes applied the entire way. Your brake pads will fade and start to disintegrate long before you come close to heating your rotors enough to soften them to the point where they could possibly warp"

I even doubt machining could fix any appreciable warp (as in potato chip), and even if it did, I wouldn't want any rotors from _that_ shop. :) "In addition, if your brake system is working properly, it's applying equal pressure to both sides of the rotor which means BOTH SIDES are heating at the same rate. To warp a brake rotor, you must have more heat on one side of the rotor than the other."

I'm not going to argue with you on that as cast iron has a relatively low melting point where our question is can a rotor typically get to that point on a passenger vehicle whose owner suspects his rotor warped (as in potato chip).

"To get cast iron hot enough to soften the metal you'd need to generate almost 2,300°F range. There isn't a factory stock automotive brake system in the world that's capable of generating that kind of heat. In fact, you would experience brake pad fade, pad disintegration, brake fluid boiling and rotor discoloration long before you reached 1,000°F."

The only thing I harp on is I've never met a person who claimed it was "warp" (as in potato chip) who actually measured it, and, worse, the remedy often is something (like rebedding) which couldn't possibly have fixed warp (as in potato chip).

Worse than even that, is all the reliable sources say passenger vehicle rotors can't warp (as in potato chip) simply because brakes can't generate enough heat.

I knew what I'd find in brake warp when I just looked it up as I did my research long ago (just as I did with cellphone caused accident rates).

Most people work solely on intuition. Humans have the intuition of evolved monkeys.

Intuition serves humans well... sometimes. But not always.

Read this _one_ reference for a starting point on fixing that intuition.

If you don't like it, find another (there are plenty).

"To pass the J2928 rotor test, rotors must withstand at least

Note that the link I am giving you has information from the brake rotor manufacturers who themselves claim that their rotors can't warp (as in potato chip) in passenger vehicles under _any_ circumstances.

Raybestos video titled "Rotors Can't Warp":

I'm not going to harp on the issue other than to repeat my salient points. a. Rotors don't warp (as in potato chip) in passenger vehicles. Period. b. People who _say_ they did, didn't measure warp (as in potato chip). c. The temperatures needed are unattainable in passenger vehicles.

OK. But I can _easily_ find industry references that say rotors can't warp (as in potato chip) simply because they are designed _not_ to warp (as in potato chip), and, because the temperatures to cause warp (as in potato chip) are unattainable.

What does that tell us about the intuition of human beings?

Xeno, I respect you. If you can find a _single_ reference on this planet that is reliable that can show brake rotors in passenger vehicles truly warping (as in potato chip), I promise you I will _read_ that reference you find.

In summary, most people work 100% off of intuition, in my humblest of experiences, where human intuition is that of an evolved monkey.

Just as cellphones don't change the accident rate is a completely unintuitive fact, brake rotors don't warp (as in potato chip) in passenger vehicles.

Please at least read the reference provided (which is just random as I can find _plenty_ of references saying the same thing from brake manufacturers like Centric - whom I've spoken to personally about this topic).

Dial indicator with the disc mounted on a brake lathe is my choice. Much more accurate and allows you to ascertain exactly where the runout is and enables the mechanic to differentiate between such things at thickness variation, taper, hard spots and warp. A long flat edge and feeler gauges isn't going to get you there. What you also need, in particular for assessing thickness variation and taper, is a disc micrometer;

Well, as I said, I have seen it, felt the symptoms and measured the warp.

Deposition creates a *different* symptom to that caused by warp when driving. Any good mechanic should be able to differentiate.

Of all those materials, the only one in *common use* is cast iron. The downside in cars is the increase in unsprung weight. Steel is for racing cars and they are very prone to warping. Laminated steel is less prone to warping but this material/type isn't common in production passenger vehicles. More an aftermarket thing for the racing fraternity. Yje high carbon iron and ceramics are only to be found on the upper end cars.

What is *normal driving*? I used to hammer the brakes on my cars but I no longer do that - I'm aging gracefully. There is no longer an imperative to save 5 or 10 seconds on a short journey - I've all the time in the world these days and I no longer live in a capital city. I've done the tree/sea change and now live in a small rural/seaside city of 75,000 people. Drive 1 kilometre from my home and I'm out in the boonies.

When assessing serviceability of brake components I *never* rely on or use intuition. I always measure.

Warp will *create* runout. It has to.

The manufacturers specify a *minimum thickness* for rotors. It's but a simple calculation from *measurements* to work out whether a rotor will clean up and still be within spec. The is no need to measure, machine,

With sliding/floating calipers, it is quite common for rotors to get hotter on one side. It's the nature of the beast. That is why, particularly on sliders, that one pad wears out before the other.

Not everyone drives their daily driver like a grandpa. I certainly didn't back in the day.

It depends......

Well now you can say you've met one - *me*. What's more, I taught brake assessment at an automotive technical college for some 20 years and there the focus was on measure, measure, measure.

They aren't trying.

In the early days of disc brakes, the rotors were heavy and thick and could be resurfaced multiple times. Brake jobs were pretty inexpensive since rotors didn't need to be replaced, they were dropped onto a lathe. Back when I did my own brake jobs I would take the rotors to my brother-in-law's shop and he would resurface them for me, but you could also get a machine shop to resurface them for $10 each.

But the mass of thick rotors negatively affected fuel economy so much thinner rotors began to be used, and they usually can't be resurfaced even once, they have to be replaced at the same time the brake pads are replaced. They also warp much easier. It also actually became not that uncommon to replace warped rotors, but not the pads, since the pads were fine.

Bullshit.

The time to replace rotors is when they no longer meet the specs, and there are a few specs that they need to meet (cracks, thickness, gouges, etc.), but the main spec is the thickness.

I've seen many people say the bullshit you say but the fact is you measure them, like Xeno and I do, and if they're within specs, you keep them.

It doesn't matter how many brake pads you replaced.

More bullshit.

Read this before you bullshit us please.

It's impossible for rotors to warp (as in potato chip), and everyone who says they do, has _never_ measured it, least of all you, Steve.

Hi Xeno, I respect your knowledge and experience so I won't harp on it with you. I deal all the time with iKooks who can't handle the facts.

Respect me that I'm highly educated, intelligent, and I speak the facts. Hence, I simply point to cold hard non-intuitive facts & leave it at that.

I agree that rotors don't warp "as in a potato chip." Rotors do warp "as in a warped rotor."

Yeah, "as in a potato chip" would be a bit too extreme. OTOH, I have

Again, I'm going to repeat I'm highly educated, intelligent, and I've researched this subject for years, so just saying "I measured it" is like saying "I measured the earth and it's still flat, dammit".

Having taken on the iKooks with facts, rest assured I believe a lot of people strongly believe a lot of things that just aren't the case.

If a vehicle shudders while braking, people intuit that their rotors warped, and, I don't blame them for thinking that any more than I blame people for thinking the earth is flat, since it makes sense in terms of the intuition of a smart monkey - which is the intuition we _all_ have.

Including me.

The only difference with me is I don't trust my intuition. Most people trust their intuition well neigh more than they do the facts.

Whenever that happens, I simply ask those people to provide facts backing up their claims, and, rest assured, they never do (because they can't).

Rest assured in most of those cases I _do_ supply the facts, as I did here. Almost all the time they don't even read the cited references. Worse, they deny every fact in them _without_ even reading them.

There's no way to carry on an adult conversation with people like that. As I said from the start, intuition is a terrible thing indeed.

You learn that when you learn quantum physics, for example. There, intuition is _always_ wrong.

The reason is that we own the intuition of monkeys... all of us. Including me.

That's why I don't trust my intuition. I trust in facts.

My intuition says that rotors should get hot and start "warping"; but the facts say otherwise, just as my intuition says that cellphones must be causing increased accident rates; but the facts say otherwise.

What I find most interesting is people blame me for their intuition being wrong, where they should blame evolution for giving humans the intuition of a monkey.

BTW, with respect to the iKooks, what MARKETING does is play on intuition. Same with automotive fluids, brake pads, tires, and, yes, rotors.

Intuition is a terrible thing for a whole bunch of reasons, the most important of which it is almost always wrong - but the next most important reason is that marketing preys on people's intuition.

If marketing gold plates the letters on the marquee, people "think" it's better, or, more to the point, if a car simply has DTV caused by pad deposition, the shop tells them they need new rotors and pads (and maybe even new calipers and a few other things too).

On the pads, if MARKETING throws in a spec of dust and calls it "ceramic" people think it too is better (they don't even know what the cold/hot friction ratings are as that is an unimportant detail to them - all that matters is that MARKETING called it "ceramic"), and if they put the word "performance" on a tire, people think it's better too.

The list of false beliefs people own based on a hijack of their intuition by MARKETING probably will never end, at least until humans evolve further away from having the intuition necessary to grab a branch that is far away and intuit that it will hold up their bodies under the force of gravity.

BTW, gravity is _another_ thing people intuit, where it doesn't even exist. But that's a topic for folks who have a background in space & time were we're moving in an orthogonal dimension to space at nearly the speed of light (which is felt by we monkeys as what we call the "force" of gravity).

Anyway, I provided my references, and folks are welcome to read them.

If someone has a reliable reference that speaks of "warp" as if it really can happen, I'll read it, but rest assured, no reliable references will be found because it's impossible for rotors to do what people intuit they do.

Doesn't matter if the rotor is solid or not, if they're sold in the USA, they meet a spec that makes it impossible - as the fluid would boil well before the rotor could get hot enough, and the rest of the brake system components would disintegrate well before the rotor ever got hot enough.

In summary, on the topic of rotor "warp", I'll read any reliable reference that people bring up to back up their intuition, but otherwise, there's no sense in this as it's like trying to explain to people that the earth isn't in the center of the solar system if they intuit otherwise and if they believe their own intuition far more than they believe in actual facts.

Intuition is a terrible thing indeed.