Welcome Guest ( Log In | Register )

Bump Topic Topic Closed RSS Feed
126 Pages « < 37 38 39 40 41 > » Bottom

Outline · [ Standard ] · Linear+

 Mountain Biking Heaven V12, Live to Ride, Ride to Live

views
     
Lord_darkslide
post Nov 5 2009, 12:28 PM

On my way
****
Senior Member
537 posts

Joined: Jan 2003
From: kuala kangsar/UPM
there's nothing wrong with carbo or alu... its just the worry issue is there...

In terms of crash worthiness.....Assume same thickness:
- Aluminum is easier to dent... if it loses shape.. it snaps (not bend like steel)
- Carbon fibre is harder to dent but if does crack the weave... it will also snap.

sorry in advance...but i wanna quote this...

same thickness and form... in a compression test....

alu let say at 50N (thats means 50 newtons of force)... it will deform...then we know the alu is not safe to use anymore....
but carbon fibre... at the same stress level... it still can resist the force..... so carbon good....no doubt about it... but...
the main worry/dilemma is...carbon will fail with out notice...it just snaps.... when it reach the ma stress level...

let say...
1 alu bar than can withstand 50N pressure...
compare with
1 carbon bar that can withstand 50N pressure also.....

of course the carbon bar is lighter/smaller... but NOT stronger since is it design to fail at the same level of stres...
but we came to the main issue... how carbon react to stress and how it fail... carbon shatters/snap when reach the max level pressure.. but alu will crumble... (again in compression test)... at the 1st point of crumble... we can already tell the alu bar is not safe edi... but the carbon bar only can be seen by naked eye when it snaps...


oh... again.. mtb and airplane and f1... dont compare... even alu used in airplane is different grade than mtb...
same as carbon... space grade, military garde... and so on is different....

i have to check the design of the wings of plane using carbon... because what we learn at uni last time.. aircraft designer prefer alu because of the flex characteristic and great cold/thaw characteristic....

Added on November 5, 2009, 12:38 pmadd:

i have no grudge agains alu or carbon... nor i have preference on both...
is just that even alu break...and carbon break... shit happens... we all sakit 1....hehehehe

just my 2 cent worth of exp and 1 time lab exp... didnt show which 1 is superior than which... every compound have it strength and weakness.... just ask the $$$ and how u r using the material.... then u'll find the best material for you... be it scandium, tataniam, carbon, alu or wood... etc


than... it all back to...... how the material is manufacture... and how confident r u to use it... thats all....

This post has been edited by Lord_darkslide: Nov 5 2009, 12:38 PM
dickybird
post Nov 5 2009, 01:00 PM

Look at all my stars!!
*******
Senior Member
2,093 posts

Joined: Apr 2005
wow! for that to happen you need to be using to the extreme everytime, like in space flight.
you ride around kiara will reach that level of usage meh? also, kif you ride cheaply, sure you ride softer right? if break then no more ride right?
like a famous mtb designer said, cheap, light and strong, PICK 2.
of course i woud like to ride a Ti bike, then no need worry about fatigue life (its infinite!) but v mahal! so for now, alu can la!
timothyy
post Nov 5 2009, 01:03 PM

Do Not Underestimate the "Pawa" of the Dark Side
*******
Senior Member
4,504 posts

Joined: Jul 2005
From: Planet Naboo
Kekeke... a simple search brought me to some previous forums in elsewhere... if got time read la...

» Click to show Spoiler - click again to hide... «



And this is for unker boner and unker syphon....

» Click to show Spoiler - click again to hide... «
bonesboy
post Nov 5 2009, 01:45 PM

New Member
*
Junior Member
34 posts

Joined: Jul 2007
From: Bonerland
QUOTE(timothyy @ Nov 5 2009, 02:03 PM)
Kekeke... a simple search brought me to some previous forums in elsewhere... if got time read la...

» Click to show Spoiler - click again to hide... «

And this is for unker boner and unker syphon....

» Click to show Spoiler - click again to hide... «
tq unker tim. but will be using my old 1 back for our ride. pls bring it along wit u this sunday. thx
TechnoDude94
post Nov 5 2009, 02:04 PM

Happiness Advocate
*******
Senior Member
6,738 posts

Joined: Dec 2006
From: Kuala Lumpur, Malaysia | Eau Claire, Wisconsin
QUOTE(dickybird @ Nov 5 2009, 01:00 PM)
wow! for that to happen you need to be using to the extreme everytime, like in space flight.
you ride around kiara will reach that level of usage meh? also, kif you ride cheaply, sure you ride softer right? if break then no more ride right?
like a famous mtb designer said, cheap, light and strong, PICK 2.
of course i woud like to ride a Ti bike, then no need worry about fatigue life (its infinite!) but v mahal! so for now, alu can la!
*
But there's no bicycle frame that's made of pure Ti.
To build that would cost a bomb. If not mistaken, Ti bicycle frame are mixed with certain alloys. hmm.gif
radmaszeal
post Nov 5 2009, 02:16 PM

boredom is caused by lack of ignorance
******
Senior Member
1,546 posts

Joined: Aug 2005
From: botfly heaven
just to clarify things, the standard for strength calculation is in N/m^2, which is force/over area. but when designing a bike frame, other considerations have to be taken, which is density of the material, cost, ease of manufacturing/production, etc etc.

the reason alu is widely used is that it is easily malleable, so many shapes can be formed (hydroformed), and stiffness can be obtained by making the effective diameter big and reducing wall thickness. so it may be stiff and can resist bending forces from head tube and BB, but any direct impact to the wall of the tube (like hitting a tree sideways, or bike falling on rock) would cause alot of damage, like cracks.

steel cant be as easily manipulated, so they cant exactly make oversized and hydroformed tubings out of it. in terms of Young's Modulus, steel is very high. higher than titanium. only problem is the density, so the stiffness to weight ratio isnt the best.

carbon can be easily manipulated according to the particular purpose and loads, with uni directional CF strands made to withstand a force from a particular direction, which is good for chainstay construction, making power transfer better. there are too many variables with carbon fibre construction, so you cant exactly generalize.

in terms of stiffness, the value most important is Young's Modulus. but tensile strength and yield strength is also important to avoid failure of the material.

in engineering usually performance index calculations are done to choose the best material for a particular purpose.

I'm actually studying materials selection this semester laugh.gif
dickybird
post Nov 5 2009, 02:17 PM

Look at all my stars!!
*******
Senior Member
2,093 posts

Joined: Apr 2005
all metals used in bikes are alloys. ti is expensive period.
radmaszeal
post Nov 5 2009, 02:21 PM

boredom is caused by lack of ignorance
******
Senior Member
1,546 posts

Joined: Aug 2005
From: botfly heaven
QUOTE(TechnoDude94 @ Nov 5 2009, 02:04 PM)
But there's no bicycle frame that's made of pure Ti.
To build that would cost a bomb. If not mistaken, Ti bicycle frame are mixed with certain alloys. hmm.gif
*
nothing is pure. except maybe distilled water laugh.gif

but in terms of metals, it would cost a lot to purify something. even gold is 99.99% purity, no 100%. and weapons grade purifying uranium/plutonium is much purer than the ones used in nuclear reactors, and the nukes dropped during WW2 were said to use up 50% of the whole US electric power generated for a few years just to purify.


but in terms of engineering metals, adding other metals would increase the strength of the alloy compared to a pure metal.
study materials science and you'll know laugh.gif

Added on November 5, 2009, 2:22 pm
QUOTE(dickybird @ Nov 5 2009, 02:17 PM)
all metals used in bikes are alloys. ti is expensive period.
*
all metals everywhere are either alloys or in oxide form. period laugh.gif

This post has been edited by radmaszeal: Nov 5 2009, 02:22 PM
TechnoDude94
post Nov 5 2009, 02:23 PM

Happiness Advocate
*******
Senior Member
6,738 posts

Joined: Dec 2006
From: Kuala Lumpur, Malaysia | Eau Claire, Wisconsin
QUOTE(radmaszeal @ Nov 5 2009, 02:21 PM)
nothing is pure. except maybe distilled water
but in terms of metals, it would cost a lot to purify something. even gold is 99.99% purity, no 100%. and weapons grade purifying uranium/plutonium is much purer than the ones used in nuclear reactors, and the nukes dropped during WW2 were said to use up 50% of the whole US electric power generated for a few years just to purify.
but in terms of engineering metals, adding other metals would increase the strength of the alloy compared to a pure metal.
study materials science and you'll know
Added on November 5, 2009, 2:22 pm
all metals everywhere are either alloys or in oxide form. period laugh.gif
*
I see, thanks for clarifying. notworthy.gif
Seems like there's a lot of chemist/engineers in this thread.
Lord_darkslide
post Nov 5 2009, 02:38 PM

On my way
****
Senior Member
537 posts

Joined: Jan 2003
From: kuala kangsar/UPM
rad...
hell yeah.... +1.....dun sleep in class like me.. later cant explain to ppl properly... heheheh...

yeah... used to study that subject... but now after working... the only important knowledge to have is...... how to "fan" the boss.... wahahahaha......j/k

back to mtb...
what do you guys think of mud guard/crud catcher? any 1 use them..? any good?
TechnoDude94
post Nov 5 2009, 02:54 PM

Happiness Advocate
*******
Senior Member
6,738 posts

Joined: Dec 2006
From: Kuala Lumpur, Malaysia | Eau Claire, Wisconsin
QUOTE(Lord_darkslide @ Nov 5 2009, 02:38 PM)
rad...
hell yeah.... +1.....dun sleep in class like me.. later cant explain to ppl properly... heheheh...
yeah... used to study that subject... but now after working... the only important knowledge to have is...... how to "fan" the boss.... wahahahaha......j/k
back to mtb...
what do you guys think of mud guard/crud catcher? any 1 use them..? any good?
*
I used to have a mud guard (on the rear) to prevent the mud from my rear tire to dirty my shirt/jersey.
End up it got broken when my friend hit into my rear after I slammed my brakes while he couldn't do it in time. tongue.gif
sendoh_7
post Nov 5 2009, 03:26 PM

On my way
****
Senior Member
520 posts

Joined: Apr 2006
the point is..to design a bicycle frame is not easy tongue.gif
chamelion
post Nov 5 2009, 03:33 PM

Back to Bricking
*******
Senior Member
2,755 posts

Joined: Dec 2004
i almost get the rear fender yesterday. but after install at bike in shop for visual, the idea was drop. uncool factor is 120%..

Trail..

» Click to show Spoiler - click again to hide... «
leinnz
post Nov 5 2009, 04:15 PM

oldfags
*****
Senior Member
755 posts

Joined: May 2005
From: Back to the Historic
hei what about scandium frame?
it is lighter than carbon. is it durable.
I saw a GHOST frame which is made of scandium. dam light. reaching 9kg
TechnoDude94
post Nov 5 2009, 04:21 PM

Happiness Advocate
*******
Senior Member
6,738 posts

Joined: Dec 2006
From: Kuala Lumpur, Malaysia | Eau Claire, Wisconsin
Uncle Sniper, is it worth it to get a brand new, full carbon road bike + full Shimano Tiagra groupset for RM7k (nett)? The handlebars/stem/seatpost/saddle are also carbon and the complete bike weighs only 5.2 kilos!
radmaszeal
post Nov 5 2009, 04:26 PM

boredom is caused by lack of ignorance
******
Senior Member
1,546 posts

Joined: Aug 2005
From: botfly heaven
QUOTE(leinnz @ Nov 5 2009, 04:15 PM)
hei what about scandium frame?
it is lighter than carbon. is it durable.
I saw a GHOST frame which is made of scandium. dam light. reaching 9kg
*
its actually aluminium scandium. an aluminium alloy. scandium in itself is expensive and rare.

some literature on scandium

http://www.eastonbike.com/downloadable_fil...%20Scandium.pdf

http://en.wikipedia.org/wiki/Scandium

too busy to read, just google only laugh.gif
mousepad87
post Nov 5 2009, 04:30 PM

***
******
Senior Member
1,008 posts

Joined: Nov 2007
From: Gombak,serdang
lol. pure engineering stuff!

dont forgot shape is also important. bow shape frame strong in compression compare to diamond shape. but the question is ? will it fail in compression or bcoz of car crash haha just kidding.

btw if the frame distribute pressure equally then it is ok. to know exactly what frame distribute stress equally we can do finite element. but I prefer to leave to pro to do that. Pro = branded name = higher R&D = safer

This post has been edited by mousepad87: Nov 5 2009, 04:32 PM
radmaszeal
post Nov 5 2009, 04:34 PM

boredom is caused by lack of ignorance
******
Senior Member
1,546 posts

Joined: Aug 2005
From: botfly heaven
some extra reading regarding scandium aluminium alloy. lol

http://www.home.no/al-sc/

btw

best tube shape to resist torsion AND bending? assuming the same effective diameter. not counting the tubing profile.

user posted image

Added on November 5, 2009, 4:38 pmand yet more literature regarding scandium alloy.


WARNING: SCIENCE CONTENT

http://www.home.no/al-sc/papers/Scandium%2...s%20Reviews.pdf

just flipped through, too lazy to read.

This post has been edited by radmaszeal: Nov 5 2009, 04:38 PM
mousepad87
post Nov 5 2009, 04:45 PM

***
******
Senior Member
1,008 posts

Joined: Nov 2007
From: Gombak,serdang
i dont think the frame u post a great frame to resist torsion n bending. the frame it self convert force to torsion (angular frame member).

my personal point of view is bow shape frame is gud for XC. and bigger tube between wheel and frame join should be bigger. one of highest stress point.

I prefer frame made by corratec
TechnoDude94
post Nov 5 2009, 04:50 PM

Happiness Advocate
*******
Senior Member
6,738 posts

Joined: Dec 2006
From: Kuala Lumpur, Malaysia | Eau Claire, Wisconsin
Woa, this thread seems to be about bicycle material/construction already...
« Next Oldest · The Sports Channel · Next Newest »
 

126 Pages « < 37 38 39 40 41 > » Top
Topic ClosedOptions
 

Change to:
| Lo-Fi Version
 0.0183sec    0.53    6 queries    GZIP Disabled
Time is now: 20th December 2025 - 08:02 AM
All Rights Reserved © 2002- 2025 Vijandren Ramadass (~unite against racism~)
Removal Request
Powered by Invision Power Board © 2025  IPS, Inc.