Physics talk

[Dave-]

But this same point keeps coming up, what you find out about being textbook right, only gets you to almost being real world right. Thats when you have to listen to people with real world experience, and fit their observations into your model rather than just posting simplist equations.

Just checking here but...

when you say "textbook right" you mean scientifically proven?

and when you say "real world experience" you mean observation right?

[bogan]

Just checking here but...

when you say "textbook right" you mean scientifically proven?

and when you say "real world experience" you mean observation right?

Textbook right, is when a myriad of factors are left out so the answer is solvable using only the major factors (which is fair enough otherwise it would be overwhelming and exams would take days). Like how they ignore air drag/velocity in most ballistics problems, or ignore adhesion and mechanical interlocking in grip problems, or ignore temperature fluctuations in components and fluids...
You'll get the marks, but you also need to realise how much these ignored secondary effects change the real world result. It's why people like Drew laugh at you when you try to explain what he's observed for ages doesn't happen; don't forget that scientific theory often begins with an observation.

[Dave-]

Textbook right, is when a myriad of factors are left out so the answer is solvable using only the major factors (which is fair enough otherwise it would be overwhelming and exams would take days). Like how they ignore air drag/velocity in most ballistics problems, or ignore adhesion and mechanical interlocking in grip problems, or ignore temperature fluctuations in components and fluids...
You'll get the marks, but you also need to realise how much these ignored secondary effects change the real world result. It's why people like Drew laugh at you when you try to explain what he's observed for ages doesn't happen; don't forget that scientific theory often begins with an observation.

You didn't go to university huh?

[Drew]

You didn't go to university huh?

Bloody hell, you're a dick.

I typed out half a page trying to get you to CONSIDER our point of view. I deleted it and felt better straight away.

To have a debate, requires both parties trying to see the other side. Otherwise it's just arguing, and that is as productive as masturbating with a cheese grater. Slightly amusing, but mostly, painful.

[ducatilover]

You didn't go to university huh?

Fuck, even I did.


So, I haven't remembered everything in this, but has anybody actually given the correct anwser as to why the drag tyes grow so much? I don't recall seeing it and it's not centripetal force.
I imagine it'd be the same reason why bike tryes will grow under severe acceleration and high speed riding.

Sidewalls are stressed more than people think even in acceleration, this creates heat, tyre and air inside tyre expands. (It's easy to see the incredible stress a tyre is under when you're throwing ~8000hp at it)

Thank you.
I should have taken physics at uni though, it looks fun (more hot chicks in Psych and Sociology though)

[Drew]

Fuck, even I did.


So, I haven't remembered everything in this, but has anybody actually given the correct anwser as to why the drag tyes grow so much? I don't recall seeing it and it's not centripetal force.
I imagine it'd be the same reason why bike tryes will grow under severe acceleration and high speed riding.

Sidewalls are stressed more than people think even in acceleration, this creates heat, tyre and air inside tyre expands. (It's easy to see the incredible stress a tyre is under when you're throwing ~8000hp at it)

Thank you.
I should have taken physics at uni though, it looks fun (more hot chicks in Psych and Sociology though)

Not to my understanding.

The tyre is pretty much un supported in it's tread ceter. The momentum of any section of that tyre tries to carry on forward in a straight line from any spot in the circle. It can do this a littel bit due to flexability in the construction. Bingo, the outer diameter of the tyre increases.

You can carry on arguing it as much as you like Dave, but I have SEEN this with my own eyes. New chain and sprockets on a mates bike, and a new tyre at the same time. Went 190/55 instead of 180/55 on the rear hoop, and had the axle quite a long way further forward. Was all sweet till we got the the motorway, and his bike starts smoking like it's blown up. FUCK!!! Slow down and the smoke is coming from the tyre. Why? Can't figure it out, musta had something caught between tyre and swing arm. Take off, and repeat the process.

Tyre expansion happens! I don't give a fuck what you THINK is MEANT to happen, because I have WATCHED what does happen.

[bogan]

You didn't go to university huh?

Hahahahahaha, 8 years and counting sonny

Sidewalls are stressed more than people think even in acceleration, this creates heat, tyre and air inside tyre expands. (It's easy to see the incredible stress a tyre is under when you're throwing ~8000hp at it)

But the expansion starts and stops a bit rapidly for heat conduction through rubber I would think? Still, with that much surface area it'll definitely have made significant changes by the end of the strip.

[ducatilover]

Not to my understanding.

That's my (obviously limited, I look at tits to much) understanding in relation to drag car tyres, which are designed to grow, through expansion, from heat generated by work. Stand next to one during a burn out, the tyres grow, and stay that size, then they grow more going down the run
Get slightly too much wheel slip on one side, it'll hop around and slam you off the track, why? Heat from wheelspin. The tyre that hooks up less will expand more, you can see it

[Drew]

Hahahahahaha, 8 years and counting sonny



But the expansion starts and stops a bit rapidly for heat conduction through rubber I would think? Still, with that much surface area it'll definitely have made significant changes by the end of the strip.

Increased pressure pushes the side wall out as well. So no dice on that increasing the circumerence.

[schrodingers cat]

Pressure comes up 1psi for approx every 6 degrees of temp.

With all this high level university talk the function of tyre construction esp sidewall cord layout has been ignored

Q: What is the difference between University and Polytech

A: At University you're taught to wash your hands after you've been to the toilet

At Polytech you get taught not to piss on your hands

[Drew]

That's my (obviously limited, I look at tits to much) understanding in relation to drag car tyres, which are designed to grow, through expansion, from heat generated by work. Stand next to one during a burn out, the tyres grow, and stay that size, then they grow more going down the run
Get slightly too much wheel slip on one side, it'll hop around and slam you off the track, why? Heat from wheelspin. The tyre that hooks up less will expand more, you can see it

The circumference isn't being expanded with the heat, the tyre is being inflated by it. So the bottom bit isn't as flat (straight) after the burnout.

[ducatilover]

Hahahahahaha, 8 years and counting sonny



But the expansion starts and stops a bit rapidly for heat conduction through rubber I would think? Still, with that much surface area it'll definitely have made significant changes by the end of the strip.

During the "war, the tyres" process they rears will be doing over 120mph

[Drew]

Pressure comes up 1psi for approx every 6 degrees of temp.

With all this high level university talk the function of tyre construction esp sidewall cord layout has been ignored

Q: What is the difference between University and Polytech

A: At University you're taught to wash your hands after you've been to the toilet

At Polytech you get taught not to piss on your hands

I have mentioned tyre construction, it's not pertinant to making my point, to delve into the specifics.

[ducatilover]

The circumference isn't being expanded with the heat, the tyre is being inflated by it. So the bottom bit isn't as flat (straight) after the burnout.

So it's the hot air and inertia stuffs going round and round in circles making the drag tyre taller? (apart from distortion from the bazillion NM of torque)

WHY ARE THERE SO MANY POSTS AT ONCE!!!!!!!!

[Drew]

So it's the hot air and inertia stuffs going round and round in circles making the drag tyre taller? (apart from distortion from the bazillion NM of torque)

WHY ARE THERE SO MANY POSTS AT ONCE!!!!!!!!

My description earlier as to why the center of the tyre grows, happens as the RPM of the tyre increases. The burnout is used to make the tyre surface sticky, they just start the tyre low on pressure, because the increase is a side effect.

Yeah, posts seem to have appeared without warning.