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.
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.
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.
> Which is good, because it turns out that lower pressure, when coupled with flexible tires, is actually lower resistance than high pressure.
Yes, on rough (real world) road surfaces, rolling resistance is lower. (Ignoring aerodynamic drag of a larger tire profile.) On smooth surfaces like velodromes, skinny tires at stupid high pressures are faster. (I only bring this up because I race at a velodrome.)
For bicycle tires (at least), this is true I guess, but the sealant is going to degrade to the point where one may not be able to ride that bike that's been set up tubeless for a few years, without changing out the sealant.
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.
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.
You are right 28mm is currently a common road tire width, but that's the total external tire width. What I mentioned rising from about 17 to (not yet common, but getting there) 25mm is the inner rim with - the narrowest measure between opposing rim flanges.
As a recovering bike mechanic of 20 years (my retirement goal is to be able to afford doing that job again, it’s joyful but hard to make a living) the writing has been on the wall for several years about the many benefits of wider tires (and rims too I suppose). From fewer puncture flats, to greater comfort and traction, to actually lower rolling resistance, I dknt see a move back to narrower tires being something that ever happens and I couldn’t be happier about that fact! I’m too slow and old to reap any performance benefits, but my comfort and enjoyment of wider tires makes me ride my bike more. https://www.renehersecycles.com/bq-tire-test-results/
Completely argee - I use 35mm tires on my 'road' (repurposed gravel) bike since ages because I just like it that way and never felt the need to go narrower.
C17 rims are considered very narrow in road cycling these days. It's been a few years since 17mm were new and upcoming. Campagnolo widened their Zonda wheelset to C17 in, easy to remember, 2017 and they were late.
The goal of performance oriented riders (for many, fixated might be the more accurate description) these days is to run the widest possible rim that will still hold their tire width of choice reasonably well. This has several reasons. One is that wind tunnel treats have repeatedly shown that there's an aerodynamic sweet spot where the rim is slightly wider than the tire, despite the increase in total frontal area for a given tire width (google "105 rule"), another is that riders want the suspension benefits of lower pressure but as little as possible of the downsides of the extra drag of wider tires, the extra mass of wider tires, increased danger of pinch flats and decreased lateral stability. Wider rims help with all those compromises.
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.
One of the more evil variations I've heard of involves pinning a bb or pebble between the cap and valve pin, creating a slow leak that's invisible until you think to take off the cap.
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.
this is why people shouldn't pipe compressed air in PVC. PVC is rated for 300psi (iirc). However, it derates pretty quickly in cold temperature. If 150psi of air is pressurizing PVC pipe and it ruptures, its going to be a terrible day. Where if water pressurizes PVC pipe and it ruptures, its just a little messy.
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.
> 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.
That was the case on some nicer cars when automakers stopped providing spares. But many cars today come with neither a spare nor run-flats. Many now are shipping with a normal tires, an inflator, sealant, and a roadside assistance telephone number.
> 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.
Spare tires under normal operation are dead weight which is the costliest possible engineering compromise to make on a vehicle, as it decreases every performance characteristic: acceleration, deceleration, cornering, fuel economy, etc.
Their only reason for existing is to compensate for the historically poor observed reliability of tires. This has recently improved with TPMS mandates and better engineered tires.
AAA estimates 220 million flat tires annually in the US.[0]
The existence of spare tires has nothing to do with poor observed reliability. It is because of lack of 100% reliability. It's because when people get a flat, they don't want to be stuck and have to be towed. They want to be able to do something about it and get back on the road. All my flats have happened not because I lacked TPMS sensors but because something poked right through. Low tire pressure only accounts for 15% of flats. [1]
If you work for AAA, then sure, trying to convince people to get rid of their spares makes sense. But waiting around for AAA doesn't sound like a fun plan for me, especially when they won't be able to put a spare on for me, but will have to tow me somewhere.
Not having a spare is definitely a problem when you need it. But a spare is needed so rarely today. And that is a major, major advance.
One hundred years ago, a car with two spare tires were not that unusual--tires were sufficiently unreliable that you might not manage a trip without _two_ flats, but tires improved, and now the only long-overland back-country adventurers carry two.
A hundred years ago, spare tires were also carried in a somewhat more visible and easy to access location. I'm sure "symmetry" was a consideration in having two as well.
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.
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."
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!).
> 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.
>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.
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.
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).
Even then it is more about showing off your wealth than comfort. You can afford several slaves just to carry you around. Probably more comfortable than walking (unlike a wagon), but not by much.
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.
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.
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.
> 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.
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.
> 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.
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?
Do you have evidence of this? While the US does use diesel electric locomotives. If you take a look at UNP for example, the majority of their locomotives were all built since the 90s and up. While I agree that emissions historically have not been at the forefront of business decisions, fuel usage certainly is and these companies have made improvements in fuel efficiency where it makes sense. Calling them 1950s locomotives is flat out wrong.
While I believe electricity is indeed the future for much of the world. I am not sure if its a slam dunk case with US rail lines today. Thinking at a high level for freight. Its possible that freight lines will go over leased tracks or tracks not otherwise not owned by the locomotive operator. So maybe it makes sense to only electrify specific lines, you not only introduce the upfront cost of electrifying which IIRC is a 2-3x (someone correct me if I am wrong) cost of just the existing tracks, you will also require different rail maintenance yards, require crews that know how to both operate and fix electric locomotives. Electricity is awesome but it won't be an easy sell to implement.
Locomotives will not be able to replace semi's. I am ignoring the fact they are run on diesel because I think this can and will change. The last mile will always be an issue. Additionally I believe most rail networks already run near capacity. Building more rail is a difficult task.
Electric does have done advantages it also has a fairly massive ongoing reoccurring cost, the electric transmission and delivery systems are expensive and requires expensive skilled labor to maintain.
Gasoline and Diesel are miracles, they carry vast sums of energy for little very weight.
Rail moves vast sums of cargo on trips over 600 miles, if the cargo is going less than 600 miles, odds are it's on a truck, but for expedited delivery operations, long haul single driver freight loads have mostly vanished, that business goes by train then truck for the last mile.
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
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.
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.
I would definitely count pipelines as vehicles, for a few reasons:
1. it removes some need to use other vehicles, the same as any of the other transportation modes, and at quite high volume
2. it may be stationary, but still has “engines” in the form of pumping stations
3. it actually requires auxiliary vehicles for continued operation, in the form of employees traveling up and down the pipeline access roads in trucks or even with helicopters; this would be an interesting part of the calculation
4. there actually are movable parts of pipelines, called “pigs” in the transalaska pipeline: scrubbers that move up and down inside the pipeline, removing the solid material that accumulates on the interior walls
They aren’t just a long piece of cylindrical metal sitting there passively.
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.