Should we all bother with Titanium ?



larryb's accident - CF bike, impact at approx 50mph with Honda GoldWing, a motorcycle

Other person - Ti bike, impact at approx 50mph with a CAR.

Sorry mate, these are not similar accidents. Had man on Ti bike hit a Honda GoldWing at the same speed you did and suffered worse injuries, then you would have a very very tiny basis for possibly claiming the CF bike might have contributed to your lesser injuries. As it is, there is no comparison.
 
alienator said:
Gee, funny you should mention that. I think I kinda do understand that whole physics thing. Do you? Do you understand how complicated the equation of motion for a body coming off a bicycle is? Do you have a grasp of the constitutive equations? Do you even have a clue as to the kinematics and injury processes involved in different accidents?

Until you do, you'll continue to apply physics badly. F=ma what a laugh! You will specifically need to know the mass moment of inertia for each long portion of each limb, for the torso, and for the head. Then you'll need to know the effective moment of inertia for the whole body, but be careful: that effective moment will be time and position dependent, so you'll need to buff up on your partial differential equations.

On your way to your incorrect conclusions, you made the typical doofus mistake. When your bike was hit by the Gold Wing, you were not restrained on your bike. Your body and limp brain continued moving until it hit said Gold Wing. Therefore, any "crumple zone" had zero effect. It's the same in cars: crush zone doesn't do squat for an unrestrained passenger since there is nothing to reduce that passengers energy until said passenger strikes the steering wheel, dash, windshield, and etc., incurring gruesome injuries.

It's apparent that you need to return to high school so you can review basic physics. I am willing to tutor you, however I charge extra for "slow" students.
Wow dude in AZ graduate school.
Maybe you have learned something from the US education system.
Glad you are here. stick with the books and someday you might get your degree, if you can pass the examines and do *original* research.

Why buy TI rather than CF?
That question has many components.

I have raised the safety aspect.
To spur on discussion, i have compared 2 similar accidents...
identical accidents, no. similar.
to draw any inferences, assumptions have to be made.
if you are uncomfortable making assumptions and qualifying your response, then you have no clue what is happening.

Some folks have brought information to the table,
others bs.

I expect advanced degree holders to bring wisdon and insight.

Can you even answer this question correctly?
Why are man hole covers round?
If not, perhaps you should go back and read study your undergraduate books.
go for a ride on a TI bike and enjoy it.

study long and hard during your stay in the US, we enjoy having you here, even if you think we are a bunch of dead heads. Gee, why go to grad school in the US? if not to learn, must be something else that brought you.
 
alienator said:
Gee, funny you should mention that. I think I kinda do understand that whole physics thing. Do you? Do you understand how complicated the equation of motion for a body coming off a bicycle is? Do you have a grasp of the constitutive equations? Do you even have a clue as to the kinematics and injury processes involved in different accidents?

Until you do, you'll continue to apply physics badly. F=ma what a laugh! You will specifically need to know the mass moment of inertia for each long portion of each limb, for the torso, and for the head. Then you'll need to know the effective moment of inertia for the whole body, but be careful: that effective moment will be time and position dependent, so you'll need to buff up on your partial differential equations.

On your way to your incorrect conclusions, you made the typical doofus mistake. When your bike was hit by the Gold Wing, you were not restrained on your bike. Your body and limp brain continued moving until it hit said Gold Wing. Therefore, any "crumple zone" had zero effect. It's the same in cars: crush zone doesn't do squat for an unrestrained passenger since there is nothing to reduce that passengers energy until said passenger strikes the steering wheel, dash, windshield, and etc., incurring gruesome injuries.

It's apparent that you need to return to high school so you can review basic physics. I am willing to tutor you, however I charge extra for "slow" students.
oops, i forgot your statement about no restraint on a bike.

The experienced bikers are wearing clipless peddles. The feet are restrained and they have both hands on the steering wheel.

The clipples peddles are engineered properl.y and neither rider has ankle injuries. the hand injuries are due to the handlebar being ripped from their grip. The bent position their arms and posture help to constrain them on the bike.

No restraints for bikers? come on you can do better than that.
grade: D minus.
 
Why do people need to get so personal on these subjects? Just because I don't agree with somebody else's logic doesn't mean I should **** them off!

It is highly likely that in the incident Larryb had, the fact the bike shattered meant THE BIKE transferred less energy into his leg and as a result he didn't break anything.

Any idea of a bike absorbing any energy like a car does in a crash to absorb energy and save the rider isn't likely to happen. A car has restraints and can decelerate the occupant slowly over a short but signifacant length of time.

When a cyclist hits something hard the bike stops quickly, and the rider goes flying past the bike until the they hit something hard. The bike does little to decelerate the rider and decrease the rate at which they hit the hard object.

But yes if the bike were to hit the rider then a breakaway design would reduce the impact. I had a friend who crashed badly on a MTB, he broke the seat post with his stomach (down hill position) and his cycling computer with his nose. I'm sure hes happy the seat post broke rather than impale his intestines, but he still hit the handle bars pretty hard with his face and also broke his arm in the tumble.

When thinking about buying a material that is designed for crashing I'd rather have a material that can take the more common small impacts like hitting another cyclist and tumbling, or a car pulling out in front of me and the bike and I slamming into the side of the car (not as big as a head on). I've hit the side of a car, as I'm sure many out there have. I don't know many people who have head on crashes and are still riding (including a dead college), so picking a bike designed to help in this case isn't a big factor for me, because in the end the car will win, bike or otherwise.

I'd rather have a bike design for more common situations, and will remain safe to ride, and if it isn't safe it is easy to tell.
After hitting the side of a SUV at lowish speed, and being a big guy (98kg), I'm very concerned about the front end of my Al frame cracking. I cracked my helmet in this accident and hurt my elbow but no sign from any part of the bike that there was any damage done there. None the less I'm watching for ANY sign of cracking in the forks and head tube area.

I would prefer Ti or steel in this situation. I know a guy with an old steel frame that was backed over by a car. He had the chain stay bent back into place and still rides the bike. He's not a big guy but that bike has done plenty of kms since then. Can't do that with carbon (or even Al).

Quite frankly all materials used on bikes have thier merits when crafted well, and I can't deside which I want for my next bike. Economics is more likely to be the decider, not one particular attribute over the other.
 
Phill P said:
I would prefer Ti or steel in this situation. I know a guy with an old steel frame that was backed over by a car. He had the chain stay bent back into place and still rides the bike. He's not a big guy but that bike has done plenty of kms since then. Can't do that with carbon (or even Al).
Back to topic. Can Ti tubes be reworked?
 
larryb said:
Maybe you have learned something from the US education system.
Apparently you have not learned how to spell, punctuate, or form complete sentences beyond the 3rd grade level from that same education system. :eek: This does not bode well for your ability to determine which side of your bread you should butter, much less anything else.

I'm sure any shop you walk into would be glad to take your Disability check for a CF frame, a Ti frame, or any other pricey bike gear that you think will better save you in a crash, when really you should still be riding your Schwinn Stingray.

Thanks for playing.
 
larryb said:
oops, i forgot your statement about no restraint on a bike.

The experienced bikers are wearing clipless peddles. The feet are restrained and they have both hands on the steering wheel.

The clipples peddles are engineered properl.y and neither rider has ankle injuries. the hand injuries are due to the handlebar being ripped from their grip. The bent position their arms and posture help to constrain them on the bike.

No restraints for bikers? come on you can do better than that.
grade: D minus.

Pedals aren't restraints in the same way that seatbelts are. In fact, all the pedals end up doing is allowing a moment to develop in the rider, about the pedals. The release point for any pedal is so far below any failure limit for any material that it's not funny. As for arms being restraints, get real. The impulse imparted in a high speed accident is far beyond what anyone can support with their arms. Moreover, the impulse happens over a an interval that is so short that a human is unlikely to be able to respond in time. Even if the hands were able to maintain grip on the handlebars, given the location of a body's center of mass, its' likely that all the hands and their grip would do would be to impart another moment on the body, a moment located at the handlebars. There is no energy dissipation in generating a moment. In fact, said moments actually increase the likelihood of injury.

You have yet to construct a model or to apply physical laws in any logical, step-wise fashion. However, you've made quite the point of bringing up physics. Perhaps it's time that you show us what you can do with said physics.

Hey, since my ancestors were here before you white folks got here, is it alright if I stay a bit longer, what with me bein' a natural born citizen and all?
 
larryb said:
Wow dude in AZ graduate school.
Maybe you have learned something from the US education system.
Glad you are here. stick with the books and someday you might get your degree, if you can pass the examines and do *original* research.

Borrrrringgggggg.....zzzzzzzzzzzz........

larryb said:
I have raised the safety aspect.
To spur on discussion, i have compared 2 similar accidents...
identical accidents, no. similar.
to draw any inferences, assumptions have to be made.
if you are uncomfortable making assumptions and qualifying your response, then you have no clue what is happening.

You have "compared" two accidents which are entirely dissimilar. If you want to make comparisons for injury analysis, then you have better compare accidents with similar energy profiles. An average car is going to weigh on the order of 4-5 times what the Gold Wing will weigh, so travelling at the same speed, the car will have 4-5 times the energy that the Wing will have. That's a huge difference in an accident. The dynamics of the two are also completely different. The car is unlikely to have it's path changed by the bicycle, whereas the motorcycle is likely to be forced to change its position in space and thus change it's path.

larryb said:
Some folks have brought information to the table,
others bs.

And you've brought bad reasoning, inept skills at modeling accidents...

larryb said:
I expect advanced degree holders to bring wisdon and insight.

Given your skills, I think it's unlikely that you would recognize "wisdon" and insight.

larryb said:
Can you even answer this question correctly?
Why are man hole covers round?
If not, perhaps you should go back and read study your undergraduate books.
go for a ride on a TI bike and enjoy it.

Why? Did a manhole cover contribute to your accident? Do you find that asking irrelevant questions strengthens your position? Perhaps you're one who when confronted with his own mistakes, opts to change the topic so as to keep his mistakes from being fleshed out.

Hey, maybe we should all ask pointless questions. Uhmmmm....do you know how to set up a test to measure the corner frequency of an object in an optical trap so as to derive the the quality of the trap?

Wait..no.....I'm sure I can come up with something even more irrelevant......

larryb said:
study long and hard during your stay in the US, we enjoy having you here, even if you think we are a bunch of dead heads. Gee, why go to grad school in the US? if not to learn, must be something else that brought you.

Here LarryBoob is displaying examples of the stupid, ill-founded assumptions that he's prone to make. Too bad. Hopefully no one else's safety is dependent on LarryBoob's limp analytical skills......
 
Man hole covers are round because it is the only shape that illiminates the possiblity of the man hole cover falling into the hole and possibly injurying someone.

You just failed an undergraduate engr examine because you could\did not think about saftey. oh well many people muddle thru life.

I hope you have a safe ride on what ever bike material makes you happy.
that maybe the only significant difference between TI and CF.
but then, maybe there are other factors that should be considered.

so back to the discussion of why ride TI?

cu

=========================
Originally Posted by larryb
Can you even answer this question correctly?
Why are man hole covers round?
If not, perhaps you should go back and read study your undergraduate books.
go for a ride on a TI bike and enjoy it.



Why? Did a manhole cover contribute to your accident? Do you find that asking irrelevant questions strengthens your position? Perhaps you're one who when confronted with his own mistakes, opts to change the topic so as to keep his mistakes from being fleshed out.
 
larryb said:
Man hole covers are round because it is the only shape that illiminates the possiblity of the man hole cover falling into the hole and possibly injurying someone.

You just failed an undergraduate engr examine because you could\did not think about saftey. oh well many people muddle thru life.
He never answered the question. Maybe he didn't take that all important engineering class Manhole Covers 301. This sounds more like the ******** questions Microsoft asks during job interviews. Lot of good it does them since they still staff the company with developers who cannot code their way out of a paper bag.
 
larryb said:
Man hole covers are round because it is the only shape that illiminates the possiblity of the man hole cover falling into the hole and possibly injurying someone.

You just failed an undergraduate engr examine because you could\did not think about saftey. oh well many people muddle thru life.

I hope you have a safe ride on what ever bike material makes you happy.
that maybe the only significant difference between TI and CF.
but then, maybe there are other factors that should be considered.

so back to the discussion of why ride TI?

cu

What do manhole covers have to do with your accident? Oh that's right: nothing.

The manhole cover question is a way for you to distract people from the fact that your "CF saved my life" supposition is ridiculous at best and that you have yet to provide any scientifically sound reasoning as to how a CF bike would be safer in your accident.

Have fun with your manhole covers, though.
 
Russ Reynolds said:
Is it best to manufacture manhole covers from Ti or Carbon ?
I strongly vote for CF as there's no re-sale value in CF. Whereas Ti manhole covers would disappear in a flash, stolen by part-time metal merchants and create danger spots for the cycling community.
 
Russ Reynolds said:
Is it best to manufacture manhole covers from Ti or Carbon ?
Definitely carbon fibre. It's really not much use for anything else after all ...
 
KellyT said:
Definitely carbon fibre. It's really not much use for anything else after all ...
Nah, too light. It might tend to get knocked up out of the hole when hit suddenly by tires. Plus the clear coat will wear through and expose the fibers to abrasion. I am going to have to go with titanium. It's sexier and the maintainance people won't strain their backs like they do with the current covers.
 
Bro Deal said:
Nah, too light. It might tend to get knocked up out of the hole when hit suddenly by tires. Plus the clear coat will wear through and expose the fibers to abrasion. I am going to have to go with titanium. It's sexier and the maintainance people won't strain their backs like they do with the current covers.

Yeah but steel manhole covers are real.
 
So I think this all answers 1 of my original questions,

Nobody is root'n for Aluminium manholecovers hey.

Aluminium is dead in the water !!
 
Russ Reynolds said:
So I think this all answers 1 of my original questions,

Nobody is root'n for Aluminium manholecovers hey.

Aluminium is dead in the water !!
Loaded question, eh? ;)

Alu is dead unless it's scandium! :p
 
Carbon man hole covers would have great vibration absorbsion, but the worn fibres might cause punctures.
Ti covers would get stollen, but if you make any man hole cover too light they may get bounced or blown off the hole.
Why don't cast iron man hole covers rust? They are also more prone to fatigue.

I might vote for Al man hole covers. Could make them out of recycled coke cans, and anodise them cool colours. Not rust, and if you make them thick enough won't fail by fatigue, but still be light enough to pick up.

By the way man hole covers are rectangular in Australia and NZ. Our road workers are smart enough not to drop them down the man holes.
 

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