On Pneumatic Tires

https://www.scopeofwork.net/on-pneumatic-tires/

by surprisetalk • 3 years ago

110 83 3 years ago

lqet• 3 years ago

Pneumatic tires are one of these things for which "reality has a surprising amount of detail" holds. Anyone who ever changed a standard tire on a bike can attest to that. There is so much going on: wires inside the tire for stability, cloth to withstand the air pressure (which the tube cannot), beads to interlock with the rim flanges to keep the tire in place (but only when pressurized), etc.

I have witnessed bike tires where the bead/flange interlock wasn't perfect, and the inner tube was quickly swelling out between a small gap between rim and and bead until it burst with a bang that was louder than a gunshot. I once had a tire where the inner cloth was slightly damaged, and the tube was slowly creating a bulge in the tire over several days until it also burst. I found it amazing that all these counteracting forces still create something you can safely drive on, often for years, without problems.

repelsteeltje• 3 years ago

The movie clip of the Taiwan tire fabrication facility is very nice! We take so much of technology for granted.

tyingq2• 3 years ago

The amount of energy in an inflated tire is surprising...

https://www.youtube.com/watch?v=1VLhLcJJefo

gosub100• 3 years ago

there's a whole subreddit for that (and other misadventures): /r/tiresaretheenemy

andrewflnr3• 3 years ago

To be fair, truck tires are an entirely different level than most car tires. More air at much higher pressure. I did some research on what actually happens if you try to slash a tire. A car tire is only slightly risky, but a truck tire can flay your hand.

bumby• 3 years ago

This is true for any compressible fluid. Work = -pressure * delta_volume. That amount of energy is why there are different standards for stress-testing something like a pipe, depending on the medium it's carrying. Occasionally you'll see an engineer or technician stress test a pipe carrying a compressible gas similar to one carrying a liquid. I can't remember the exact ASTM standards, but I think a compressed fluid should be tested to around 110% rated pressure and an incompressible fluid at 150%. If they use the wrong one on a compressible fluid, it's putting a lot more energy in the system. If it fails, it can be a bad day.

bradley132• 3 years ago

Yup, pretty amazing. I had a bike that I rode a fair bit - same tires for 20 years. Back in the day, cars used to have flat tires pretty regularly - no longer - now some cars don't even come with the little donut wheels.

It is genuinely amazing how reliable tires have become.

jtbayly2• 3 years ago

Removing the spare tire is not an advance.

brnt• 3 years ago

I had a bike that I rode a fair bit - same tires for 20 years.

Impossible. A fair bit is 20km+ a day which is ~4000km/yr. That's in the order what an average tire is rated for (5-10Mm). Let's say you had tires 4 times as good, you still needed to change 5 times.

No1• 3 years ago

now some cars don't even come with the little donut wheels

Those cars come with “run flat” tires, which supposedly allow you to drive a few miles without damaging the wheel when the tire is flat. After which, instead of patching the tire, it must be discarded. Quite the advancement.

tpm3• 3 years ago

Modern bike wheels and tires are also moving in an interesting direction: carbon rims are increasingly made 'hookless' (straight flange without the 'hook' which locks the tire bead) because it's easier to manufacture, lighter and more aerodynamic, while tires are tubeless, which is also lighter and less prone to punctures, but then the tires are harder to manufacture and more expensive. And lower pressures must be used so the tire does not pop off the hookless rim, so the rims and tires are also getting wider to hold more air, where once 17mm inner rim width was common for road bikes, we are now getting up to 25mm.

ubermonkey• 3 years ago

28mm is actually common. That's what I have on my brand-new Giant TCR (which is to say: an aggressive, go-fast road bike).

wiredfool• 3 years ago

Lower pressure is required with wider tires (stress in the tire casing is proportional to P*r). Which is good, because it turns out that lower pressure, when coupled with flexible tires, is actually lower resistance than high pressure.

Tubeless "just" allows for lower pressures without pinch flatting. The lower limit on pressure is to have enough to keep the bead seated, and not burping air. If you run lower than that, you've got to go tublar.

mauvehaus2• 3 years ago

Hookless rims are actually a pretty old technology. I had a beater 10-speed from the '70s with hookless ISO 630 aluminum rims. Then as now, they tend to run a lot tighter tires than hooked rims, and that bike, as are many newer ones with TLR rims, was kind of a bastard to change a tire on.

Source: Among other things, I work at a bike shop part-time and have volunteered as a bike mechanic in the past.

loeg3• 3 years ago

Hookless for road bikes is a dead end manufacturing fad that only exists to increase manufacturers' margins. It does not provide any aerodynamic benefit. The weights are not substantially different. The low tire pressure maximums are not suited for road tires. The manufacturing cost savings are not passed on to consumers. Hookless might improve strength in a way that matters when tires are flat or otherwise bottom out (i.e., maybe useful for MTB, where the pressure maximums are not a concern). Hooked wheels are moving wider, too, of course. 21mm internal is now relatively common and you also see 22-24mm internal road wheels.

slingnow• 3 years ago

If you found a bike tire this amazing, I can't wait for you to discover _anything even slightly more complicated than an inflated tube inside a rubber/cloth shell_.

This reads like someone just came back from outer space and was stunned by the complexity of all of the systems that got them there. I'm all for appreciating the little things, but we have to draw the line with overdramatization somewhere.

chrismorgan• 3 years ago

[Dunlop] promptly filed a patent (it was later invalidated)

I was curious and investigated: it was invalidated because of Thomson’s patent as prior art 42 years earlier.

markx2• 3 years ago

The scale of the time and money put into Formula 1 tyre development is amazing:

"The design process took in more than 10,000 hours of indoor testing, more than 5,000 hours of simulation, and more than 70 prototypes developed virtually, to eventually create 30 different specifications that were tested by nearly all the teams over more than 20,000 kilometres."

https://www.pirelli.com/tyres/en-ww/motorsport/f1/tyres

https://www.formula1.com/en/latest/article.the-beginners-gui...

xattt• 3 years ago

10,000 hours is 416 days. They may be fudging the numbers by including simultaneous tire testing as sequential (look, we tested 4 tires for 2,500 hours = 10,000 hours!).

benj111• 3 years ago

that as late as 1570, the number of four-wheeled carriages in Britain “could be counted on one hand,”

This sounds at best misleading. 2 wheeled carts must have been more common, they're still transport, supplying the same need as a 4 wheeled cart. It isn't as if there were a hand full of wheeled vehicles total.

bradley132• 3 years ago

You're absolutely right. I think they are restricting their definition to the closest thing to today's cars: 4-wheeled, enclosed passenger carriages. Not quite fair, as two-wheeled carts, while less luxurious, certainly existed.

bluGill2• 3 years ago

In the 1500s wagon suspension technology wasn't very good. Humans would much prefer to walk if they could since riding would be very rough on the body. There wasn't really any disadvantage - humans can walk at least as far in a day as a horse (or more likely ox in 1500). Even rich people would walk, the horse would be for heavy things that you carry with you (ie a knight armor - a knight would then put the armor and and ride into battle).

There are exceptions to the above where people did ride in wagons. However they were rare as for most people walking was good. Many of the exceptions where to show off: I'm rich enough to have a wagon so I'm going to ride in it when you are looking (and if I think nobody is I'm getting out to walk).

Animats2• 3 years ago

A 4-wheeled horse-drawn fully enclosed carriage with a suspension is either a limo or a bus. You need four horses to get above walking speed. It's either an expensive luxury or mass transportation.

btbuildem• 3 years ago

In the United States, vehicles with tires carry twice as much freight as vehicles without them. Tires have an outsized role in individual transportation: The vast majority of Americans commute on tires, outweighing all other modes by about fourteen to one.

Another way to look at this is to see the pitiful state of the rail network on the continent: the most efficient way to move goods and people over land, severely underused.

The article's author is very excited about tires, but it would be good to balance the stoke with the health and environmental impacts such mass usage of tires has. Rubber dust and microplastics polution in urban centers and along transport corridors contribute to a range of negative health impacts.

Not to mention, where do discarded tires end up: https://www.amusingplanet.com/2015/01/worlds-biggest-tire-gr...

paddy_m2• 3 years ago

By Ton-Miles the US leads the world in freight hauled. But for a variety of reasons, railroads are more interested in extracting profits from existing large customers than they are in increasing mode share. A couple of reasons for this, railroads are natural monopolies with industrial facilities needing to be connected to a single rail line. The railroad companies are much more interested in hauling large bulk from single sources that are time insensitive than a heterogeneous mix of freight that needs to be switched and is competitive on timing with trucks.

This results in RR policies like precision scheduled rail (PSR), that tries to precisely utilize rail and crews to shuttle long trains across territory. PSR is only oriented to reduce RR costs. If a PSR train is late, every other train is delayed. PSR has also come alongside regularly running trains that are much longer than sidings, which makes it impossible for other trains to pass.

Everyone responds to incentives, and there are a couple of regulatory changes that could fix this.

1. Some level of regulation that penalizes RRs for delayed trains. PSR results in lower operating costs but the externality of delays isn't properly paid for by the RRs.

2. Increased technology investment like signalling improvements, positive train control and automatic couplers.

3. Some level of regulation of freight interchange along with timing and price regulations. You can send freight from an RR in Kansas to Louisianna, but you would have to go through two or more controlling RRs that would rather go point to point on their own network. I don't know what this regulation would look like.

4. Land value tax for tracks. Railroads are disincentivized from improving tracks, particularly with electrification. LVT would be hard to pass generally, but it makes a lot of sense to tax railroads less for electric tracks. Electrified tracks allow faster acceleration and electric locomotives are much more reliable than diesel locomotives.

The railroads in the US make immense profits (BNSF makes $6B in profits a year). There are severe regulatory capture problems that prevent these advancements.

I have read the Switzerland in particular has excellent freight rail that is speedy and used for smaller loads. I don't know their operating techniques that allow this.

chrisco255• 3 years ago

I bet they're leaving out freight shipped on water.

tzs3• 3 years ago

They are not. The modes the bts.gov page they cite breaks it down by are: Truck, Rail, Water, Air (including truck-air), Multiple modes and mail, Pipeline, Others and unknown, and no domestic mode.

Tossing the data in a spreadsheet and figuring percentages, the percentages of the total for those modes are: 64.6, 9.8, 4.3, 0.0, 2.8. 17.1, 0.2, and 1.2.

So 1.8 ratio of truck to non-truck, which is close enough to their claim that "In the United States, vehicles with tires carry twice as much freight as vehicles without them".

Personally, I'd exclude "Pipeline" since I wouldn't count that as a "vehicle". With that excluded the ratio of truck freight to other freight is 3.5 to 1.

ponector3• 3 years ago

Btw, sea freight between US ports is not a thing due to legacy laws.

Thousands ships you can see in the US ports are all for import/export of goods.

tzs3• 3 years ago

Another way to look at this is to see the pitiful state of the rail network on the continent: the most efficient way to move goods and people over land, severely underused.

The US has an inferior passenger rail network. It's freight rail network is fine.

In the US, freight within the country is 82% road, 12% rail, 5% water. In the EU it is 77% road, 17% rail, 6% water.

I wonder how these are actually counted? Suppose a manufacturer ships a ton of goods from their warehouse in Fresno to a retail chain in New York. Let's say that shipment goes by truck from Fresno to Los Angeles, where it then goes by train to Chicago, and there by water to Albany in New York, and finally from there to a New York warehouse owned the retail chain.

Does that count as 1 ton by road, rail, and water? Or is it going to have some kind of weighting by mileage?

If it is not weighted than road is going to be several times rail nearly everywhere, because there are a lot of things shipped locally which is almost always going to be cheaper and faster by truck than rail. On top of that most things that go by rail are also going to go part of the way by truck, since most things aren't both produced and consumed close to railroad stations and so it is mostly likely a truck that gets them to and/or from the train.

hypercube33• 3 years ago

Our freight network is running on 1950s diesel electric locomotives so I wouldn't call it fine. Electric has shown it's better just had a huge upfront cost (even though regeneration can probably pay for cost long term even in some setups).

Also if it's fine why is most of the cargo moved by diesel semi?

NegativeLatency• 3 years ago

Found that stat kinda confusing because some trains do have tires: https://en.wikipedia.org/wiki/Railway_tire and most if not all cargo planes land on runways with tires

Johnny555• 3 years ago

It's a lot less confusing when you realize (based on your own link) that freight trains do not typically (if ever) have rubber tires, they are general used for passenger rail systems.

And while airplanes do have rubber tires, few people would say that the freight is carried on tires when the tires are only used for a tiny percentage of the trip. If pneumatic tires were never invented, airplanes could still exist, they'd land on non-pneumatic tires, skids, or some other method.

I think only someone looking for confusion would be confused by someone saying that rail freight and aircraft do not travel on rubber tires.

sudobash1• 3 years ago

The tire’s meteoric rise might have surprised nineteenth-century observers of the wheel.

To be somewhat pedantic, tires were in use for the nineteenth century and earlier. Tire generally refers to anything wrapped around a wheel making contact with the ground. Before pneumatic tires, there were iron tires. These were wrought iron rings placed around wooden wagon wheels.

Obviously the article is talking about pneumatic tires here, but I thought that I'd note that there are other, prior types.

jasonjmcghee• 3 years ago

I read “On Pneumatic Tries” and was trying to imagine what “Pneumatic” could possibly mean in the context of a trie. Like dynamic node expansion?

But then it was about tires.

hoyd• 3 years ago

I lived a couple of years in Stonehaven, a lovely small town south of Aberdeen, Scotland. This town was the birthing place of Robert Thomson, the inventor of the pneumatic tyre.

danans• 3 years ago

It’s difficult for me to conceive of a world without pneumatic tires.

It may not be difficult to conceive for much longer:

https://michelinmedia.com/michelin-uptis/

Granted, they are still tires, but just not pneumatic.

WheatMillington• 3 years ago

I've seen pictures of similar designs and captions about how the tire is about to be obsolete since I started using the internet 30 years ago.

AlbertCory• 3 years ago

I don't see anything about SALB (South American leaf blight) which has still kept South America from large scale rubber production.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2759241/

Kal Penn has an 8-part series on the world economy, one episode of which highlights what a disaster if would be if this disease ever spread to Southeast Asia.

Alarmist? Maybe, I don't know. I know that there don't appear to be any direct flights from Rio to Bangkok, although I didn't look all that hard.

MichaelRo• 3 years ago

As a kid in vacation at my grandparents, I'd ride in one of these, a wagon pulled by cattle, with no rubber tires but same technology used 4000 years ago: https://cdn.adh.reperio.news/image-1/1a50f3f9-77af-4588-ae4c...

Well... sometimes, other times I'd just prefer a good ol' walk to the bone shaking.

thimkerbell4• 3 years ago

How do I bookmark a site so HN will preferentially show me posts that link to it? Scope of Work is a find.

Cockbrand• 3 years ago

Are you looking for this? https://news.ycombinator.com/from?site=scopeofwork.net

thimkerbell4• 3 years ago

Yes, that gives me the site's past articles, but I want the future ones to come to me.

On Pneumatic Tires

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