Page 3 of Bicycles 2006 by Litespeed

cruising tensile strength measures the force required to pull a material apart in frame design more tensile strength means that less material is needed thereby saving weight fatigue strength measures how far and how many times a material can be flexed before it breaks certain materials such as steel and titanium can be tooled to withstand an infinite number of flexes without failure yield strength measures how much force it takes to permanently bend a material as with tensile and fatigue strength more is better the very high strength levels of titanium again allow less material to be used which saves weight elongation refers to the percentage a material will stretch before tearing or cracking ideally you want a material that will give slightly before failure thus providing a safety factor corrosion resistance titanium is virtually impervious to heat cold fresh water salt water sweat ultraviolet light infrared light and petroleum based chemicals this means low low low maintenance for the bicycle frame density the most important analysis of density for cycling applications is the material s density relative to its strength and durability simply stated density is the weight of a material for a given volume such as pounds per cubic inch or grams per cubic centimeter titanium actually weighs the most of the 3 primary frame materials in this evaluation at .160 lb sq.in with aluminum at .098 lb/sq.in and carbon-fiber at .065 lb/sq.in toughness refers to how much a material can deform or be damaged before failure the near mythical toughness-to-weight of titanium is why it is so often used in military armor on the other hand aluminum is an extremely tough raw material but manufacturing lowers the fatigue strength dramatically carbon fiber has virtually no resiliency once it is dented or over-flexed so catastrophic failure can result from what might seem to be minor damage careful consideration of each of these factors is critical when designing a highperformance bike frame because the true performance is the result of how all these factors work together top tube 35 seat tube 24 down tube 16 chainstays 7 seatstays 6 other 12 sprinting/climbing down tube 55 seat tube 16 top tube 10 chainstays 7 seatstays 3 other 9 hard braking down tube 58 top tube 26 seat tube 5 chainstays 4 seatstays 1 other 6 vertical impact seatstays 32 top tube 29 down tube 18 seat tube 9 chainstays 7 other 5 .034 6|4 cold-worked ti 3|2.5 cold-worked ti 6|4 cold-worked ti 175,000 psi 87,500 psi the minute you clip in and start off you subject your bike frame to remarkable stresses even cruising creates strong flexion torsion compression and tension forces on your frame the type and intensity of force is different at every point on the frame our research into frame stress analysis see fig 1 has given us tremendous insight into where these forces are concentrated and how they are applied this data is an aphrodisiac to our engineers who dream of new ways to counter these stresses using the data we compile throughout the critical testing process they are continually exploring the ways that different tubing cross sections can counter the individual forces involved in riding see fig 2 the more effectively they do their magic the higher performance they can squeeze out of the tubing thus increasing the strengthto-weight ratio thus reducing the amount of material needed to maintain the existing standards recently we have developed innovative proprietary forming technology p.f.t that has allowed our geeks to really get out there and achieve performance results that were never before possible on a production frame the introduction of geometrically enhanced tubing or g.e.t a few years ago greatly improved our ability to do more with less now we have taken that technology and pushed it way out of the existing envelope we d love to tell you how we do it but we d have to kill you .044 .040 .048 .046 .042 fig 1 frame stress analysis of different riding applications ultimate tensile strength in pounds/sq in 150,000 psi 3|2.5 cold-worked ti yield tensile strength in pounds/sq in carbon composite 115,000 psi carbon composite fatigue strength in pounds/sq in 115,000 psi 57,500 psi 160,000 140,000 120,000 100,000 80,000 60,000 40,000 20,000 80,000 70,000 60,000 50,000 160,000 140,000 120,000 100,000 80,000 60,000 40,000 20,000 3|2.5 cold-worked ti 11 3|2.5 cold-worked ti 180,000 90,000 180,000 66,000 psi 6|4 cold-worked ti 155,000 psi elongation in percentage of stretch in 9 varies based on direction of fiber and resin carbon composite 100,000 psi 6|4 cold-worked ti 6061-t6 aluminum 8 9 carbon composite 6061-t6 aluminum 30,000 20,000 10,000 6061-t6 aluminum 14,00 psi 40,000 psi 40,000 7 5 6061-t6 aluminum 45,000 psi 5 .070 .064 .060 .068 .054 .050 .058 .066 .038 .056 .036 .062 .072 .052 fig 2 vectors of force application during pedal cycle material 4 litespeed.com you might be surprised just how much stress a frame is subjected to under normal riding conditions let alone the extremes of sprinting and climbing just be content to marvel at the results of our development we proudly present the p.f.t super tubesets in select models of the 2006 litespeed lineup performance comparison .074 5 litespeed.com

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