Does the type of carbon really make a difference?
08-05-08 | 01:11 PM
#26
Has coddling tendencies.
Joined: Jul 2005
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From: Topanga Canyon
Bikes: 2008 Blue RC8 w/ '09 Rival
Quite the science, this carbon fiber as a building material. The resin creates the stiffness, and the weight, while the cloth creates the linear strength and flexibility. The specific mix of resin and cloth, the number of layers, as well as the fiber direction, is the ongoing experiment to create the ideal frame. The latest development has been the addition of tiny carbon tubules into the resin, which serves to displace more resin during the manufacturing process, thus reducing weight without sacrificing strength and flexibility.
For those who might not know, whenever you see a layer of carbon fiber cloth on a frame, fork or component, you're looking at the cosmetic layer. The functional layering beneath that visible layer has a much different, less aesthetically pleasing look.
For those who might not know, whenever you see a layer of carbon fiber cloth on a frame, fork or component, you're looking at the cosmetic layer. The functional layering beneath that visible layer has a much different, less aesthetically pleasing look.
08-05-08 | 01:19 PM
#29
SD
Joined: Jun 2007
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From: San Diego
Last edited by paul_858; 08-05-08 at 01:34 PM.
08-05-08 | 01:28 PM
#30
Has coddling tendencies.
Joined: Jul 2005
Posts: 8,360
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From: Topanga Canyon
Bikes: 2008 Blue RC8 w/ '09 Rival
yep. The functional cloth has a much smaller, tighter weave. It wouldn't look like much to the eye. For dramatic, eye catching effect, the "fat" cross weave pattern is layered over top. Performance CF frames that are painted do not have that cosmetic layer.
08-05-08 | 03:11 PM
#32
Has coddling tendencies.
Joined: Jul 2005
Posts: 8,360
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From: Topanga Canyon
Bikes: 2008 Blue RC8 w/ '09 Rival
Can't quite tell from the picture, but what kind of finish is that on the tubes? Unfinished? That's the design? Chances are they've mixed a fine charcoal colored powder into the resin to give it that dull matte look. Possible they created a CF tubing slightly oversized during manufacture, then sanded down to the final diameter.
08-05-08 | 03:42 PM
#33
location:northern Ohio
Joined: Jul 2006
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Sounds to me like the quality of CF frames has too many variables, much like a cell phone contract,to really follow what your buying.Who honestly does a physical study on the fiber +resin content on there new weenie machine?I assume the quality changes with each frame made in a line of similar models.
You can bet your sweet chamois cover the manufactures like it this way,the "ole mushroom treatment".
You can bet your sweet chamois cover the manufactures like it this way,the "ole mushroom treatment".
08-05-08 | 04:15 PM
#34
ugg
Joined: Dec 2005
Posts: 601
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From: CA- bayarea
Bikes: Steelman road & a plastic Deda
Custom builders bikes are also tuneable for different ride feel to user requests. I had very specific requests in my build and Brent selected the material best for the application. His tubes are unidirectional and come from Edge composites in Utah then hand wrapped instead of mono or lugged
08-05-08 | 05:19 PM
#35
Race to train
Joined: May 2005
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From: suffering on the back
sorry, Brent Ruegamer. www.ruesports.com
08-24-09 | 04:24 AM
#36
Newbie
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M30S, T-700 and T-800 are simply manufacturer designations for that particular weight and modulus of carbon fibre.
What is more important to the use of carbon fiber in bicycles are the exact values of its weight, strength and modulus.
The Modulus of Elasticity (I'll just call it modulus), is how much the material stretches when stressed. This value is directly related to how stiff the material is. A high modulus material like Toray's M40 carbon fiber is very elastic and resilient compared to Toray's M30S carbon fiber, which is much stiffer and stronger in tension and torsion. Because the M30S fibers are stiffer, they are more likely to break when they are stressed to much. The M40 fibers will continue to stretch while not breaking when they reach their threshold. It is possible to deform high modulus fibres however.
Modulus is measured in GPa (Gigapascals). High Modulus materials are in the 250-350 GPa range, while low modulus/high strength materials are in the 100-250 GPa range.
Using a high modulus material reinforced by a low modulus/high strength material in certain areas is how most frames are constructed.
Using high modulus fibres for the seatstays will allow them to bend and give a little when they are compressed. Conversely, using low modulus/high strength fibers in an area that sees a lot of torsion and tension, like the bottom bracket or headtube, will make that area of the frame stiffer than the high modulus material would.
What is more important to the use of carbon fiber in bicycles are the exact values of its weight, strength and modulus.
The Modulus of Elasticity (I'll just call it modulus), is how much the material stretches when stressed. This value is directly related to how stiff the material is. A high modulus material like Toray's M40 carbon fiber is very elastic and resilient compared to Toray's M30S carbon fiber, which is much stiffer and stronger in tension and torsion. Because the M30S fibers are stiffer, they are more likely to break when they are stressed to much. The M40 fibers will continue to stretch while not breaking when they reach their threshold. It is possible to deform high modulus fibres however.
Modulus is measured in GPa (Gigapascals). High Modulus materials are in the 250-350 GPa range, while low modulus/high strength materials are in the 100-250 GPa range.
Using a high modulus material reinforced by a low modulus/high strength material in certain areas is how most frames are constructed.
Using high modulus fibres for the seatstays will allow them to bend and give a little when they are compressed. Conversely, using low modulus/high strength fibers in an area that sees a lot of torsion and tension, like the bottom bracket or headtube, will make that area of the frame stiffer than the high modulus material would.
I've found that on a Taiwan bike manufacturer website. Even if there isnt all different type of carbon, it give's us an idea how it works
https://www.dynamic-bicycles.com/fron...ategory=300429
Here's also a link with good pics showing & explaining the difference between 1k 2k 3k 12k and UD (uni-directional)
https://www.storckbicycle.com/usa/ind...&s=carbonfiber
Last edited by Totenkopf; 08-24-09 at 05:43 AM.
08-24-09 | 04:48 AM
#37
Still can't climb
Joined: Sep 2006
Posts: 23,024
Likes: 6
From: Limey in Taiwan
M30S, T-700 and T-800 are simply manufacturer designations for that particular weight and modulus of carbon fibre.
What is more important to the use of carbon fiber in bicycles are the exact values of its weight, strength and modulus.
The Modulus of Elasticity (I'll just call it modulus), is how much the material stretches when stressed. This value is directly related to how stiff the material is. A high modulus material like Toray's M40 carbon fiber is very elastic and resilient compared to Toray's M30S carbon fiber, which is much stiffer and stronger in tension and torsion. Because the M30S fibers are stiffer, they are more likely to break when they are stressed to much. The M40 fibers will continue to stretch while not breaking when they reach their threshold. It is possible to deform high modulus fibres however.
Modulus is measured in GPa (Gigapascals). High Modulus materials are in the 250-350 GPa range, while low modulus/high strength materials are in the 100-250 GPa range.
Using a high modulus material reinforced by a low modulus/high strength material in certain areas is how most frames are constructed.
Using high modulus fibres for the seatstays will allow them to bend and give a little when they are compressed. Conversely, using low modulus/high strength fibers in an area that sees a lot of torsion and tension, like the bottom bracket or headtube, will make that area of the frame stiffer than the high modulus material would.
What is more important to the use of carbon fiber in bicycles are the exact values of its weight, strength and modulus.
The Modulus of Elasticity (I'll just call it modulus), is how much the material stretches when stressed. This value is directly related to how stiff the material is. A high modulus material like Toray's M40 carbon fiber is very elastic and resilient compared to Toray's M30S carbon fiber, which is much stiffer and stronger in tension and torsion. Because the M30S fibers are stiffer, they are more likely to break when they are stressed to much. The M40 fibers will continue to stretch while not breaking when they reach their threshold. It is possible to deform high modulus fibres however.
Modulus is measured in GPa (Gigapascals). High Modulus materials are in the 250-350 GPa range, while low modulus/high strength materials are in the 100-250 GPa range.
Using a high modulus material reinforced by a low modulus/high strength material in certain areas is how most frames are constructed.
Using high modulus fibres for the seatstays will allow them to bend and give a little when they are compressed. Conversely, using low modulus/high strength fibers in an area that sees a lot of torsion and tension, like the bottom bracket or headtube, will make that area of the frame stiffer than the high modulus material would.
i've seen descriptions of low density and high density. which one is better and used in the more expensive bikes?
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08-24-09 | 09:32 AM
#40
Certifiable Bike "Expert"
Joined: May 2005
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The Modulus of Elasticity (I'll just call it modulus), is how much the material stretches when stressed. This value is directly related to how stiff the material is. A high modulus material like Toray's M40 carbon fiber is very elastic and resilient compared to Toray's M30S carbon fiber, which is much stiffer and stronger in tension and torsion. Because the M30S fibers are stiffer, they are more likely to break when they are stressed to much. The M40 fibers will continue to stretch while not breaking when they reach their threshold. It is possible to deform high modulus fibres however.
2) You say that M30S is "much stiffer and stronger in tension and torsion". Incorrect. M30S is less stiff, but stronger (see above). It is meaningless to say that it is stronger in torsion; the individual fibers are not stressed in torsion.
3) "Because the M30S fibers are stiffer, they are more likely to break when they are stressed to much." This is incorrect. All carbon fibers are brittle. They do not have any meaningful plastic deformation.
4) "The M40 fibers will continue to stretch while not breaking when they reach their threshold. It is possible to deform high modulus fibres however." I am not sure what you mean by "their threshold"; it seems you are getting confused with the behavior of metallic structures (yield and plasticity). Carbon fibers do not plastically deform; they break when their threshold (ultimate strength) is exceeded.
Last edited by Phantoj; 08-24-09 at 12:48 PM. Reason: fixed url
08-24-09 | 12:02 PM
#41
Senior Member
Joined: Jul 2007
Posts: 106
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From: Los Angeles, Ca
Bikes: Litespeed Archon, Ultimate, Palmares, Blade. BMC Pro Machine. Trek 7.3 FX Commuter
If a builder were to make a one-off, market practicality-be-damned frame of supreme lightweight and stiffness, they would use very expensive pan based T-800 unidirectional carbon fibre manufactured by Toray.
This stuff will run for about $2500 for 10 ounces or so.
A few manufacturers, or more precisely, frame builders, use this material in their frames, such as Spin, Crumpton and Storck.
Giant also purchases raw T-800 fibres from Toray and weaves them into a 1K pattern for their TCR Advanced frames and forks.
The unidirectional fibres would be layed into the mold with the fibres running along the length of the frame tubes.
This would make for a very stiff, and depending on the method of molding and construction, very light frame.
This stuff will run for about $2500 for 10 ounces or so.
A few manufacturers, or more precisely, frame builders, use this material in their frames, such as Spin, Crumpton and Storck.
Giant also purchases raw T-800 fibres from Toray and weaves them into a 1K pattern for their TCR Advanced frames and forks.
The unidirectional fibres would be layed into the mold with the fibres running along the length of the frame tubes.
This would make for a very stiff, and depending on the method of molding and construction, very light frame.
