Following, the primary methods of carbon bicycle frame production are outlined. Included are examples, benefits and drawbacks to each respective design.
| |
Pros |
Cons |
Examples |
| Carbon Tubes/Aluminum Lugs |
- Inexpensive carbon design
- Lighter than steel frames
- Traditional look
- Simple design
- Generally good impact resistance of tubes
|
- Limited by metal lug design
- Weak spot at lugs susceptible to catastrophic failure (due to galvanic corrosion, thermal expansion, or inadequate bond)
- Fail to optimize benefits of carbon
- Bonded and blind-riveted parts
- Discontinuity of materials leads to non-optimized ride quality
- High stresses at joints
- Non-repairable
|
- Look KG series
- Time Helix
- Older Trek 2000's
|
| Carbon Tubes Bonded to Aluminum Tubes |
- Least expensive way to add carbon to a welded frame
- Lighter than steel frames
- Traditional look
- Simple design
- Generally good impact resistance of tubes
- ustom geometry possible
|
- Fail to optimize benefits of carbon (particularly fatigue resistance and vibration damping)
- Carbon/aluminum interface not insulated, causing galvanic corrosion over time
- Discontinuity of materials leads to non-optimized ride quality
- Overlap of the two materials at joints create redundant structure
- Non-repairable
|
- Pinarello Prince
- Many other Taiwanese-sourced brands
|
| Carbon Tubes Bonded to Titanium Tubes |
- Inexpensive way to add carbon to a welded frame
- Lighter than steel frames
- Traditional look
- Simple design
- Generally good impact resistance of tubes
- Custom geometry possible
|
- Fails to optimize benefits of carbon (particularly vibration damping)
- Adhesive bonding to titanium can be difficult to do properly
- Discontinuity of materials leads to non-optimized ride quality
- Overlap of the two materials at joints create redundant and heavier structure
- Non-repairable
|
- Seven Odonata
- Serotta Ottrott
- Several other Taiwanese-sourced brands
|
| Carbon Tubes/Molded Carbon Lugs |
- Lightweight
- No galvanic corrosion problems at lugs
- Better approach than metal lugs
- Good cost-benefit ratio (Trek OCLV and Calfee Luna)
- Custom geometry possible (although difficult)
|
- Uneven load path at the lugged joints causes the forces to concentrate at the bonded interfaces leading to possible failure. (unless accommodated with substantial bond surface area)
- Use of blind rivets and bonding-on of fixtures (opportunity for warranty problems to surface)
- Bladder molded lugs have seams, parting lines, and discontinuous wall thickness (Trek only)
- Extensive use of aluminum for head tube sleeve, bottom bracket, and drop-outs (except for the Luna and Dragonfly which employ aluminum insulated from the carbon with fiberglass and uses Ti dropouts)
- Use of body filler and requires paint to cover the filler (Trek only)
- Uneven distribution of stresses at joints (although Luna and Dragonfly have tapered lugs)
- RTM fabricated Lugs have high resin-fiber ratio and are expensive (Colnago only)
|
- Trek OCLV
- Parlee
- Colnago C-40
- Calfee Luna and Dragonfly
|
| Foam-Core |
- Ability to form complex shapes (aerodynamic, aesthetics)
- Can create a stiff frame
- One-piece molded version can have continuous fiber flow in shell
|
- High void contents
- Irregular compression over foam core
- Expensive
- Use aluminum sleeves/dropouts
- Seams and parting lines created in molding process
- No weight savings
- Foam susceptible to water absorption
- Limited sizing due to expensive molds
|
- Softride Ironman (no longer in production)
- Zipp 2001 (no longer in production)
- Parts of Aegis and Kestrel frames
|
| Bladder-Molded |
- Ability to create complex shapes
- Continuos flow of material over molded areas
- One-piece frames won't catastrophically fail
- Easily repaired
|
- Limited sizes and geometries
- Seams and parting lines intrinsic to bladder molded frames and/or lugs
- Difficult to control wall thicknesses
- Use drill and bonding structural carbon to affix parts
- Use aluminum and cro-moly parts
- Impact resistance at "tubes" not as good as with pre-fabricated tubes
- Increased surface area of complex and aerodynamic shapes increases weight
- Necessary use of body filler and paint
- Difficult in getting consistent quality
- Bonded areas (in multi-piece structures) susceptible to failure
|
- All current Kestrels
- Aegis
- Trek OCLV lugs
- Giant
- EPX
- Other Taiwanese brands
|
| Carbon Tubes/Carbon Joints/Pressure Lamination |
- Lightweight
- Fatigue life for fiber reinforced joints is appreciably longer than that of adhesive bonds
- Carbon-to-carbon laminations create optimal joint strength and stress flows
- Lugless frame construction
- No unreinforced drilled holes in the structural carbon
- Use of structural reinforcing gussets to replace seams and for increased lateral stiffness
- All primary metal parts are made of titanium
- Highly customizable to specific rider geometry, rider weight, and riding style
- Easily repaired
|
- Limited aerodynamic frame benefits
|
- Carbonframes Sapphire and Tetra
- Calfee Tetra
- 1991-1993 LeMond Carbon
|
