Originally Posted by urbanknight

In response to your actual question, it would be fascinating to measure the decibel level of such a blowout. The closest I could find on the internet was a car tire which apparently is about 88dB from 50 feet away. Instant hearing loss occurs at about 130dB and a tire blowout is definitely not a sustained sound, so you'd need to reach that to have a true need for hearing protection.

Anybody got a decibel meter and want to purposely wreck some tubes?

Originally Posted by livedarklions

You're postulating a "safety" factor over the recommended max of some size. If you don't really know what that factor is (if indeed it does exist), any time you exceed the spec, you are testing that.

Missed the point on the metal fatigue thing, I see. You were claiming "so far, so good". My point is you really don't know that because you may be accelerating metal fatigue or creating some that wouldn't otherwise occur. Your answer to that is other things can cause metal fatigue, I guess, and that's a profoundly stupid answer.

I'm pretty sure I don't want to be near your steam engine, btw. What you write about running that over spec has the "famous last words" ring to it.
https://allthatsinteresting.com/gene...im%20instantly.

Originally Posted by smd4

My point isn't about comparing the thickness of a bicycle rim to the thickness of a boiler (you'd be surprised how thin the metal is, relatively speaking), or about the relative pressures. Although that's all you guys seem able to focus on.

Originally Posted by LarrySellerz

Metal fatigue? Which material are you referring to, and what is causing the fatigue?

Originally Posted by smd4

My point isn't about comparing the thickness of a bicycle rim to the thickness of a boiler (you'd be surprised how thin the metal is, relatively speaking), or about the relative pressures. Although that's all you guys seem able to focus on.

As I said, it's about the safety factors the manufactures build into their products. In the case of locomotive boilers, they were routinely proof-tested to four times their MAWP. So in the case of our steam locomotive, the calculated bursting pressure would be about 760 PSI. We never even get CLOSE to that pressure.

Do you really think a rim manufacturer is going to actually put the fail pressure on its rim? Would the lawyers allow that? Or do you think it's more likely that a company like Mavic (whose rims I use, and which did not have a "max" pressure sticker on them when manufactured), would maybe make their rim's failure pressure a little higher than the max? Maybe even 2 times, if not more?

Originally Posted by genejockey

And in Larry's case, he's talking about exceeding the recommended max pressure for both the tire and the rim, when the tire is unloaded, and then putting another 300lbs on it. I sincerely doubt he's checking the tire pressure after he puts the 300lbs on it.

Originally Posted by genejockey

Most or all of use other riders for motivation - that guy 100 yards ahead, you speed up to try and catch him. But that's not racing, that's just motivating yourself. If you catch him and pass him, it proves nothing about the two of you. You can feel good about the extra effort you put in, but you didn't 'beat' him, you didn't 'win', anymore than an e-bike 'wins' when it passes you on a hill.

It's only a race if everyone agrees it's a race. I mean, for decades here we've made fun of riders who think they 'beat' some pro or other because they passed them one time when the pro might have been on a recovery ride.

Originally Posted by livedarklions

I think you're, at best, taking what you know about boilers and extrapolating to bicycle wheels when the two have virtually nothing to do with each other.

Originally Posted by livedarklions

The reason the margin for boilers is so high is because historically there were multiple instances of large numbers of people being killed or maimed by exploding boilers.

Originally Posted by livedarklions

You're postulating a "safety" factor over the recommended max of some size. If you don't really know what that factor is (if indeed it does exist), any time you exceed the spec, you are testing that.

Missed the point on the metal fatigue thing, I see. You were claiming "so far, so good". My point is you really don't know that because you may be accelerating metal fatigue or creating some that wouldn't otherwise occur. Your answer to that is other things can cause metal fatigue, I guess, and that's a profoundly stupid answer.

I'm pretty sure I don't want to be near your steam engine, btw. What you write about running that over spec has the "famous last words" ring to it.
https://allthatsinteresting.com/gene...im%20instantly.

Originally Posted by genejockey

Different metal, different purpose. Not built for maximum lightness. The era of the steam locomotive was a time when they overbuilt things, rather than running on the hairy edge of failure.



. I sincerely doubt he's checking the tire pressure after he puts the 300lbs on it.

Originally Posted by LarrySellerz

We just have different perspectives on how we ride, which is totally fine. If I want to treat every encounter with another rider as a legitimate race, and it makes me enjoy my ride more because of it, there's nothing wrong with it.

Originally Posted by LarrySellerz

Im bad at math, but I used to be good at math and my gut tells me that its a pretty simple calculation to see how much the pressure increases due to weight. Someone has done this for sure. its an interesting question, I doubt it changes more than 5 psi but I really have no idea.

Originally Posted by genejockey

Different metal, different purpose. Not built for maximum lightness. The era of the steam locomotive was a time when they overbuilt things, rather than running on the hairy edge of failure.



No, but the point is YOU DON'T KNOW how much higher you can go. You know how high they're willing to guarantee it for, so assuming you know what the margin is, as I said, a fool's game. And in Larry's case, he's talking about exceeding the recommended max pressure for both the tire and the rim, when the tire is unloaded, and then putting another 300lbs on it. I sincerely doubt he's checking the tire pressure after he puts the 300lbs on it.

Originally Posted by genejockey

You'd need to know how much the volume changes.

Originally Posted by LarrySellerz

then what use that pvnrt math stuff we learned in 10th grade? if we gotta measure the volume change (which probably depends on the tire) it gets way more complicated damn I should really get to work, could probably ask some people there

Originally Posted by livedarklions

Apply the inverse square rule and I'm pretty sure the car tire explosion is more than deafening at 5 feet.

Originally Posted by genejockey

Oh, I don't mind. As long as he's careful with the water level and doesn't make too many assumptions.

Originally Posted by genejockey

We rode on the Gettysburg Railroad a few months before they had a minor boiler explosion (firebox roof blowout without catapulting the boiler all the way to Carlisle.) Turns out the crew assumed the water glass was accurate and didn't check using other methods. Only one of the operators for the railroad REALLY knew what he was supposed to do, and he wasn't on that trip.

Originally Posted by urbanknight

Would still be fascinating to try and test it with bicycle tires. I have blown a few improperly seated tubes in my life and don't recall any ringing in my ears afterward, but it would be fun to put actual numbers to it.

Originally Posted by smd4

I blew one tire when I worked in the shop. Can't remember if it was a road tire or a MTB tire. I suspect road. I don't recall ringing, but it was certainly one of the louder things I have ever heard.

Originally Posted by genejockey

Dude. What do you think the "V" stands for.

Originally Posted by urbanknight

It certainly startles the !@#$ out of you, am I right?

Originally Posted by smd4

Precisely.

That uncontrolled release of steam ("explosion") caused a re-write of the entire set of federal regs re boiler inspection and operation.

Originally Posted by urbanknight

This calculator (remember decibels are not linear) suggests otherwise (108dB @ 5'). At 1' it comes to 122dB.
https://www.omnicalculator.com/physi...ce-attenuation

Would still be fascinating to try and test it with bicycle tires. I have blown a few improperly seated tubes in my life and don't recall any ringing in my ears afterward, but it would be fun to put actual numbers to it.

Originally Posted by Chuck M

Larry outdid himself with this thread. I’ve lost track of all the arguments but many of them aren’t even arguing with Larry at this point.

A+