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DANGER: Trek multitrack 7300 (hybrid) aluminum bracket sheers off, rips apart entire rear end of bike
Hi,
Because this is a hybrid I'm not sure whether to place it in racing or off-road. But here goes my story. Saturday afternoon I was riding along a clean flat nature trail; no sticks in the gears, no nothing. I was going at an even speed of about 20-25mph in the next-highest gear when all of a sudden I hear a *SNAP*, then something smashed into the rear spokes, causing an almost instant stop. I was lucky I wasn't going downhill when this occurred, or I would've flown over the handlebars. It turns out that a small piece of the aluminum frame supporting the gear shifter wore out due to metal fatigue. The shifter mechanism ripped off the aluminum frame, got caught in the rear spokes, and destroyed the entire rear end of the bike. Several spokes are broken and/or bent. The shifter mechanism is bent in several places, the shifter wire is shredded, and the front crank apparatus also has some damage due to the sudden awkward pull on the chain. I was not happy. I had to walk 8 miles home while contending with a pair of minor stress fractures in the legs (I was biking because I can't run for the moment). I've contacted the dealer but so far no reply. This $420 bike is just barely over 2 years old, with less than 500 miles on it. I expected to get more than a dollar per mile for this bike, and I'm really not happy with Trek's poor design of this frame and model. If the dealer or Trek will support the repair of this obvious manufacturer's defect, I will keep you apprised. Dan -- rec.bicycles.off-road is moderated by volunteers. To find help solving posting problems, or contact the moderators, please see http://rbor.org/ Please read the charter before posting: http://rbor.org/rbor_charter.txt |
#2
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Dan wrote:
Hi, Because this is a hybrid I'm not sure whether to place it in racing or off-road. But here goes my story. Saturday afternoon I was riding along a clean flat nature trail; no sticks in the gears, no nothing. I was going at an even speed of about 20-25mph in the next-highest gear when all of a sudden I hear a *SNAP*, then something smashed into the rear spokes, causing an almost instant stop. I was lucky I wasn't going downhill when this occurred, or I would've flown over the handlebars. It turns out that a small piece of the aluminum frame supporting the gear shifter wore out due to metal fatigue. The shifter mechanism ripped off the aluminum frame, got caught in the rear spokes, and destroyed the entire rear end of the bike. Several spokes are broken and/or bent. The shifter mechanism is bent in several places, the shifter wire is shredded, and the front crank apparatus also has some damage due to the sudden awkward pull on the chain. I was not happy. I had to walk 8 miles home while contending with a pair of minor stress fractures in the legs (I was biking because I can't run for the moment). I've contacted the dealer but so far no reply. This $420 bike is just barely over 2 years old, with less than 500 miles on it. I expected to get more than a dollar per mile for this bike, and I'm really not happy with Trek's poor design of this frame and model. If the dealer or Trek will support the repair of this obvious manufacturer's defect, I will keep you apprised. Dan Dan, Given that TREK uses CAD/CAM and extensive quality control to design its bikes, the metal fatigue on the derailleur hanger was most likely due to damage that occurred in shipping or when the 16 year old mechanic who put the bike together at the shop you got it from took it for a spin and mashed it against a curb or something (believe it or not teenagers who make minimum wage do stupid stuff like that). One of the most common things in a crash is for the derailluer hanger to get bent. And the way most people "fix" it is to bend it back, not realizing that doing so causes substantial yet invisible metal fatigue. So calm down on the CONSUMER PRODUCT WARNING thing unless you know for a fact that defect originated in the manufacturing process. Thanks, Magilla -- rec.bicycles.off-road is moderated by volunteers. To find help solving posting problems, or contact the moderators, please see http://rbor.org/ Please read the charter before posting: http://rbor.org/rbor_charter.txt |
#3
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On Sun, 27 Mar 2005 21:16:11 CST, Dan may have
said: Hi, Because this is a hybrid I'm not sure whether to place it in racing or off-road. But here goes my story. Saturday afternoon I was riding along a clean flat nature trail; no sticks in the gears, no nothing. I was going at an even speed of about 20-25mph in the next-highest gear when all of a sudden I hear a *SNAP*, then something smashed into the rear spokes, causing an almost instant stop. I was lucky I wasn't going downhill when this occurred, or I would've flown over the handlebars. It turns out that a small piece of the aluminum frame supporting the gear shifter wore out due to metal fatigue. The shifter mechanism ripped off the aluminum frame, got caught in the rear spokes, and destroyed the entire rear end of the bike. I find a different analysis more plausible; the rear derailleur cage is much more likely to have snagged in the spokes, following the wheel around and ripping the der support from the dropout in the process. The der support tab has so little strain on it that it will not fail due to "metal fatigue" even after an extremely long period in service. There are at least three other ways by which the cited failure could occur in my experience. Several spokes are broken and/or bent. Quite typical of a spokejam due to der cage snagging. The shifter mechanism is bent in several places, the shifter wire is shredded, and the front crank apparatus also has some damage due to the sudden awkward pull on the chain. This should tell you something. Had the der mounting tab merely failed, the der would have dropped off and hung from the chain, but would not have been likely to get into the spokes; the der has to be firmly mounted and the der cage extended (which won't be the case if the der's mount breaks) in order for the cage to be able to grab the spokes. I was not happy. I had to walk 8 miles home while contending with a pair of minor stress fractures in the legs (I was biking because I can't run for the moment). I've contacted the dealer but so far no reply. This $420 bike is just barely over 2 years old, with less than 500 miles on it. I expected to get more than a dollar per mile for this bike, and I'm really not happy with Trek's poor design of this frame and model. If the dealer or Trek will support the repair of this obvious manufacturer's defect, I will keep you apprised. I suspect that failure analysis will determine that either the der had been bent prior to the incident, putting its cage swing path into the conincal region of the drive-side spokes, or that the der was stiff due to congealed lubricant producing a motion pattern that put the der into the spokes. I have had both types of failure occur; neither would be a warranty matter. Keep us informed in any event; it will be instructive for all concerned if there's an actual defect involved. -- My email address is antispammed; pull WEEDS if replying via e-mail. Typoes are not a bug, they're a feature. Words processed in a facility that contains nuts. -- rec.bicycles.off-road is moderated by volunteers. To find help solving posting problems, or contact the moderators, please see http://rbor.org/ Please read the charter before posting: http://rbor.org/rbor_charter.txt |
#4
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"Dan" wrote in message ... Hi, Because this is a hybrid I'm not sure whether to place it in racing or off-road. But here goes my story. Saturday afternoon I was riding along a clean flat nature trail; no sticks in the gears, no nothing. I was going at an even speed of about 20-25mph in the next-highest gear when all of a sudden I hear a *SNAP*, then something smashed into the rear spokes, causing an almost instant stop. I was lucky I wasn't going downhill when this occurred, or I would've flown over the handlebars. It turns out that a small piece of the aluminum frame supporting the gear shifter wore out due to metal fatigue. The shifter mechanism ripped off the aluminum frame, got caught in the rear spokes, and destroyed the entire rear end of the bike. Several spokes are broken and/or bent. The shifter mechanism is bent in several places, the shifter wire is shredded, and the front crank apparatus also has some damage due to the sudden awkward pull on the chain. I was not happy. I had to walk 8 miles home while contending with a pair of minor stress fractures in the legs (I was biking because I can't run for the moment). I've contacted the dealer but so far no reply. This $420 bike is just barely over 2 years old, with less than 500 miles on it. I expected to get more than a dollar per mile for this bike, and I'm really not happy with Trek's poor design of this frame and model. If the dealer or Trek will support the repair of this obvious manufacturer's defect, I will keep you apprised. Dan Thank God it wasn't a Bianchi. -- rec.bicycles.off-road is moderated by volunteers. To find help solving posting problems, or contact the moderators, please see http://rbor.org/ Please read the charter before posting: http://rbor.org/rbor_charter.txt |
#5
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Dan wrote:
Hi, Because this is a hybrid I'm not sure whether to place it in racing or off-road. But here goes my story. Saturday afternoon I was riding along a clean flat nature trail; no sticks in the gears, no nothing. I was going at an even speed of about 20-25mph in the next-highest gear when all of a sudden I hear a *SNAP*, then something smashed into the rear spokes, causing an almost instant stop. I was lucky I wasn't going downhill when this occurred, or I would've flown over the handlebars. It turns out that a small piece of the aluminum frame supporting the gear shifter wore out due to metal fatigue. The shifter mechanism ripped off the aluminum frame, got caught in the rear spokes, and destroyed the entire rear end of the bike. Several spokes are broken and/or bent. The shifter mechanism is bent in several places, the shifter wire is shredded, and the front crank apparatus also has some damage due to the sudden awkward pull on the chain. I was not happy. I had to walk 8 miles home while contending with a pair of minor stress fractures in the legs (I was biking because I can't run for the moment). I've contacted the dealer but so far no reply. This $420 bike is just barely over 2 years old, with less than 500 miles on it. I expected to get more than a dollar per mile for this bike, and I'm really not happy with Trek's poor design of this frame and model. If the dealer or Trek will support the repair of this obvious manufacturer's defect, I will keep you apprised. Dan -- rec.bicycles.off-road is moderated by volunteers. To find help solving posting problems, or contact the moderators, please see http://rbor.org/ Please read the charter before posting: http://rbor.org/rbor_charter.txt Your bike sounds like a prime candidate to become a singlespeed. /s -- rec.bicycles.off-road is moderated by volunteers. To find help solving posting problems, or contact the moderators, please see http://rbor.org/ Please read the charter before posting: http://rbor.org/rbor_charter.txt |
#7
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On Wed, 30 Mar 2005 07:14:36 CST, "Phil, Squid-in-Training"
may have said: wrote: Your bike sounds like a prime candidate to become a singlespeed. LOL nice way to look at it... If half the right dropout is gone, it's not much of a candidate for conversion until the dropout has been replaced. (Not to mention the possible bent stays.) -- My email address is antispammed; pull WEEDS if replying via e-mail. Typoes are not a bug, they're a feature. Words processed in a facility that contains nuts. -- rec.bicycles.off-road is moderated by volunteers. To find help solving posting problems, or contact the moderators, please see http://rbor.org/ Please read the charter before posting: http://rbor.org/rbor_charter.txt |
#8
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Werehatrack wrote: On Wed, 30 Mar 2005 07:14:36 CST, "Phil, Squid-in-Training" may have said: wrote: Your bike sounds like a prime candidate to become a singlespeed. LOL nice way to look at it... If half the right dropout is gone, it's not much of a candidate for conversion until the dropout has been replaced. (Not to mention the possible bent stays.) -- I figured he snapped off part of the hanger. Half of the dropout would be impressive. Bent aluminum stays? Really? You think? /s -- rec.bicycles.off-road is moderated by volunteers. To find help solving posting problems, or contact the moderators, please see http://rbor.org/ Please read the charter before posting: http://rbor.org/rbor_charter.txt |
#9
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On Sun, 27 Mar 2005 21:16:11 -0600, Dan wrote:
Hi, Because this is a hybrid I'm not sure whether to place it in racing or off-road. But here goes my story. *.racing trimmed off as irrelevant. Saturday afternoon I was riding along a clean flat nature trail; no sticks in the gears, no nothing. I was going at an even speed of about 20-25mph in the next-highest gear when all of a sudden I hear a *SNAP*, then something smashed into the rear spokes, causing an almost instant stop. I was lucky I wasn't going downhill when this occurred, or I would've flown over the handlebars. It turns out that a small piece of the aluminum frame supporting the gear shifter wore out due to metal fatigue. How do you figure this was due to metal fatigue? I assume that this small piece of aluminum is the derailleur hanger, which is not subject to a lot of stress under normal use. In order to claim some sort of fault of the manufacturer, you have to be able to convince them that this was the cause of the problem. The rest of the damage was collateral. In my experience, derailleurs usually snap off either because the chain dropped and got tangled in the pulleys, which then twisted the derailleur off since you were still applying pressure to the pedals, or there was a missed shift under load, causing essentially the same chain of events. I have seen both of these occur, one on the flat, and the other (the missed-shift then crunch) on a short, steep climb. One other possibility that can occur is if you shift it into the spokes, which is caused by a misadjusted derailleur. However, I don't imagine this was the cause due to the circumstances you describe. Are you _sure_ you hadn't shifted at that point, or had the chain fall off the chainring? I know it's easy for the dealer to just say it was operator error and not take responsibility, but you need an explanation why this was not the case here. If the dealer or Trek will support the repair of this obvious manufacturer's defect, I will keep you apprised. Don't be surprised if the obviousness of the defect is missed by the dealer. I don't see it, and would have to be convinced. -- David L. Johnson __o | A mathematician is a machine for turning coffee into theorems. _`\(,_ | -- Paul Erdos (_)/ (_) | -- rec.bicycles.off-road is moderated by volunteers. To find help solving posting problems, or contact the moderators, please see http://rbor.org/ Please read the charter before posting: http://rbor.org/rbor_charter.txt |
#10
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In article ,
"David L. Johnson" wrote: On Sun, 27 Mar 2005 21:16:11 -0600, Dan wrote: Hi, Because this is a hybrid I'm not sure whether to place it in racing or off-road. But here goes my story. *.racing trimmed off as irrelevant. Saturday afternoon I was riding along a clean flat nature trail; no sticks in the gears, no nothing. I was going at an even speed of about 20-25mph in the next-highest gear when all of a sudden I hear a *SNAP*, then something smashed into the rear spokes, causing an almost instant stop. I was lucky I wasn't going downhill when this occurred, or I would've flown over the handlebars. It turns out that a small piece of the aluminum frame supporting the gear shifter wore out due to metal fatigue. How do you figure this was due to metal fatigue? I assume that this small piece of aluminum is the derailleur hanger, which is not subject to a lot of stress under normal use. In order to claim some sort of fault of the manufacturer, you have to be able to convince them that this was the cause of the problem. The rest of the damage was collateral. In my experience, derailleurs usually snap off either because the chain dropped and got tangled in the pulleys, which then twisted the derailleur off since you were still applying pressure to the pedals, or there was a missed shift under load, causing essentially the same chain of events. I have seen both of these occur, one on the flat, and the other (the missed-shift then crunch) on a short, steep climb. One other possibility that can occur is if you shift it into the spokes, which is caused by a misadjusted derailleur. However, I don't imagine this was the cause due to the circumstances you describe. The other cause that I've seen has been either picking up a stick (mountain biking) or (happened to me) wheel reflector comes partly loose, twists sideways, and takes out the derailleur along the way. Keith -- rec.bicycles.off-road is moderated by volunteers. To find help solving posting problems, or contact the moderators, please see http://rbor.org/ Please read the charter before posting: http://rbor.org/rbor_charter.txt |
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