2002 Lemond Technical Manual
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GARY FISHER BICYCLES GREG LEMOND RACING CYCLES The First Name in Mountain Biking TECHNOLOGY STORIES TECHNOLOGY STORIES ZR9000 Aluminum . 7 Titanium . .4-6 Genesis geometry . .9-10 Reynolds 853 . 8 Women on Bikes . .12-13 LeMond Geometry . 11 Genesisters . .15-16 Women on Bikes . .12-13 Bike Fit . 14 LeMond women's bikes . .12-13 Sugar = B*Link . .15-16 Bike Fit . 14 Sugar+ = Sybil link . .15-16 Bontrager Wheelsystems . .15-16 29er . .15-16 The Greg LeMond Story . .26-27 Gary Fisher: A History . .24-25 Bontrager Wheelsystems . .15-16 BIKE TECHNICAL INFO, GEOMETRY, AND SPECIFICATIONS BIKE TECHNICAL INFO, GEOMETRY, AND SPECIFICATIONS LeMond Titanium . .77-79 LeMond Steel . .83-88 Sugar . .28-31 LeMond Cyclo-cross . .89-90 Sugar+ . .28-31 Genesis Hardtails . .35-42 FOR THE MECHANIC Genesisters . .43-45 Genesis Unplugged . .46-49 A Word About Torque Specifications . 91 Comfort Series . .50-53 Torque Spec and Fastener Prep . 92 City/Path Series . .54-58 Intermediate Mountain Bikes . .59-62 BMX . .63-71 Kids’ . .72-76 FOR THE MECHANIC A Word About Torque Specifications . 91 Torque Spec and Fastener Prep . 92 Sugar Pivot Service . .93-94 © Trek Bicycle Corporation 2001 1 2002 Fisher / LeMond Technical Manual All Rights Reserved For the 2002 model year, we are introducing some- in quality, yet the frame represented the heaviest part thing new to the bicycle industry- a frame material of the bicycle. Even so, I found that it was not stiff designed specifically for the manufacture of bicycles. We enough to keep the drive train in alignment during call it ZR9000. sprinting efforts. Like some of our competitors, we can wax eloquent At the time I was a student at MIT in Boston, about various laboratory tests of strength and stiffness. Massachusetts. A professor, myself, and some other Often, a new material is used as a reason to substantially students started to look at what would make a better raise the price of a bike. But as we’ve said before, the material for bicycle frames. The standard high-end bicycle frame was made of double-butted chrome ride of a bicycle is the sum of its design, manufacture, and molybdenum steel alloy tubing. Steel is easy to work material, in that order. In other words, its not the material, with, but it is very dense, making even the thin tubes but what we do with it that makes a bike ride better. of my high-end steel racing bike into a heavy struc- A great frame material should allow the designer to ture. make a better bike. If a frame isn’t lighter, better riding, Our goal was to make the frame lighter, stronger and at a better value to you, where is the benefit from this and stiffer. To meet those goals, our first criteria was a new wonder material? material less dense than steel. So the proof is in the finished product. Our models As lower density alternatives, we looked at using ZR9000 are up to 190 grams (almost 1/2 pound) Aluminum, Magnesium, Titanium, and Carbon fiber. lighter than last year. At the same time, they are stronger, While each of these looked like they might provide and have a fatigue life up to 5 times that of the comparable some benefits, we were also looking for an easy way to 2001 models. And we can deliver these awesome new bikes make a few bikes. We were hoping to find a material at approximately the same cost to you. that we could obtain easily, and assemble into a strong For some, knowing you are buying a lighter, stronger, and light frame. longer lasting bike at the same cost is enough. But we Carbon fiber needs special molds for each size and know some of you want to know more about this technol- geometry of frame to be produced. This would take ogy. To explain in more detail, we’ve asked the developer of time and cost a lot of money for prototypes. ZR9000 to say a few words: Titanium was very expensive and the welding was difficult. The entire area being heated needed to be shielded from air. Even ignoring the cost, it was dif- A MATERIAL DESIGNED FOR BICYCLE ficult to obtain in the tubing sizes we needed for bikes. FRAMES. by Gary Klein Most available tubing was CP (Commercially Pure) tita- Advertising Claims nium which did not provide much of a strength ben- efit. I’ll bet you are thinking: “Just what we need, another new bike frame material! Isn’t the field crowded and Magnesium has the lowest density of the metals confusing enough as it is? Are all of the various frame we looked at. Initially Magnesium looked good, with materials really different? Do the differences really relatively high tensile strength per weight, but it does matter? How can every material be superior to every not have the ductility of aluminum, and does not weld other one? Or are they just marketing hype?” as easily. Also the tubing sizes we needed were not readily available. Another problem was this was in Which of the claims from which companies should the Boston area, where the streets are salted in the you believe? Most of the advertised properties for dif- wintertime. We had seen what the salt does to a steel ferent frame materials are the properties of a material frame, and we knew that magnesium has an even in its highest temper state, made into little coupons lower resistance to corrosion. So it would need a real and tested in laboratory machines; not the strength good protective coating. that the frame material is in after it has been made into frame tubes, and welded or brazed into a bicycle After our research, we decided on aluminum as frame. The material may chemically be the same, but the material of choice. As we wanted the highest the advertised strength is not there. performance frame possible, we started looking at the highest strength aluminum alloys. Unfortunately, they In addition, and more to the point, the advertised were difficult to weld, to form, had corrosion problems, strength is a bulk material property and does not etc.. reflect the engineering design of the bike, such as the diameters, wall thickness, and shapes of the tubing Materials that were strong, but not weldable, would used. These have a huge influence on the overall create the need for special bonding lugs at each joint. strength of the finished frame, and at least as much These would have to be designed and machined indi- influence on the way the bike rides. Please do not vidually for each frame design, a somewhat daunting equate advertised material properties with frame dura- task. So we looked for a material where we could cre- bility, performance or low weight. If you want to ate a high strength weld with normal welding meth- compare the strength of one frame to another, you ods. probably need to test them both. And if you want to Finally we settled on 6061 aluminum. It came the compare the ride, instead of looking at charts you’ll closest to meeting all of our frame material goals. need to ride them! 6061 was the workhorse of the structural aluminum Why Aluminum? alloys, and it had most everything we desired. It is In the early 70’s, when I lined up on my first start- easily welded, machines easily, is formable at room ing line, the bikes around me weighed an average of temperature, and resists corrosion pretty well (it is about 22 pounds. My Fuji Finest was at least average used extensively for marine applications). As a real 2 2002 Fisher / LeMond Technical Manual plus, 6061 was used extensively in aircraft, so thin wall Often the frames made from 7000 alloys are not tubing was readily available in various diameters. heat treated after welding at all. In other cases they are only artificial aged after welding, which strength- Aluminum ens the material which was hot enough for long Pure aluminum is very soft. The molecules align and enough to dissolve the alloying elements, but does interconnect such that in pure aluminum, molecular nothing for the rest of the frame material. slippage easily occurs in all three directions (slip planes). As a result, it is not strong enough to make a In these cases the alloy just got hot enough to par- good bicycle frame. tially dissolve the alloying elements, or just grow the strengthening crystals to a large size which weakens By adding various alloying agents to the aluminum, the material substantially. This is called over-aging. different characteristics can be obtained. These alloys of It is similar to what happens if you leave the material aluminum have a number which describe the alloying in the ageing oven for too long a time. Some of elements. 6061 aluminum has small amounts of mag- the crystals grow larger in size, while others shrink nesium, silicon, copper, and chromium added to the or disappear. The net result is that the weld is pure aluminum. This alloy obtains its strength from strengthened, but the tubing adjacent to the weld is microscopic precipitates (magnesium silicide crystals) weakened. So even though 7000 alloys claim a higher that mechanically stop the slip planes in the aluminum strength than 6061, it is probably less after welding. crystals from sliding when force is applied. As an anal- ogy, they work like putting sand in a sliding bearing. Grain growth Aluminum alloys can also be strengthened by mechan- In my opinion, the limiting factor for designing ical working. Cold-drawing the tubing is an example aluminum frames is the fatigue life.