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Cantilevered rear aluminum dropouts
I recently purchased an aluminum-framed bicycle at a yard sale. I am
curious as to the why the rear dropout is designed the way it is. It is cantilevered more than I see on other bikes and this seems strange to me. Other bicycles have the wheel axle closer to the junction of the seat and chain stays. This design seems unnecessary and I worry about cracking of an aluminum frame. Pictures are at http://www.lobuglio.org/redbike/ The bike has no identifying information on it (no head-badge or decals). It was a charity yard sale so the owner wasn't there when I bought it. It has Shimano 105 components with a 7 speed cassette (13-28) and a double chainring up front (52-42) in the back. The rear spacing is 126 mm, so I am guessing this is late 1980's. On the bottom- right chainstay it has "B1-0302" stamped (as if by a dot-matrix printer) and on the left chainstay is the serial number (11 numbers, the first five of which are 65804). I am curious as to the why the rear dropout is designed the way it is (cantilevered) and if anyone might have any guesses as to its origin. Thanks Joe LoBuglio |
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Cantilevered rear aluminum dropouts
On Feb 1, 8:37 am, "Joe LoBuglio" wrote:
I recently purchased an aluminum-framed bicycle at a yard sale. I am curious as to the why the rear dropout is designed the way it is. It is cantilevered more than I see on other bikes and this seems strange to me. Other bicycles have the wheel axle closer to the junction of the seat and chain stays. This design seems unnecessary and I worry about cracking of an aluminum frame. Pictures are athttp://www.lobuglio.org/redbike/ The bike has no identifying information on it (no head-badge or decals). It was a charity yard sale so the owner wasn't there when I bought it. It has Shimano 105 components with a 7 speed cassette (13-28) and a double chainring up front (52-42) in the back. The rear spacing is 126 mm, so I am guessing this is late 1980's. On the bottom- right chainstay it has "B1-0302" stamped (as if by a dot-matrix printer) and on the left chainstay is the serial number (11 numbers, the first five of which are 65804). I am curious as to the why the rear dropout is designed the way it is (cantilevered) and if anyone might have any guesses as to its origin. Thanks Joe LoBuglio I'd guess it's a Cannondale. They made them that way for looks, small rear triangles were the fast look back then (and it's red!! wooo hoo!). I've got a mid-eighties Cannondale m700 and I don't worry about the cantilevered dropouts cracking, those bikes were over engineered. I'm sure someone else can help you with the serial numbers. Year and model are encoded in there somehow. Cam |
#3
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Cantilevered rear aluminum dropouts
Joe LoBuglio wrote:
I recently purchased an aluminum-framed bicycle at a yard sale. I am curious as to the why the rear dropout is designed the way it is. It is cantilevered more than I see on other bikes and this seems strange to me. It's a Crack n Fail, aka Cannondale from 94 vintage or thereabouts. The prefered failure mode is through the flattened bottom of the seatstays but as this frame has survived till now it might live a bit longer -- --- Marten Gerritsen INFOapestaartjeM-GINEERINGpuntNL www.m-gineering.nl |
#4
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Cantilevered rear aluminum dropouts
On Thu, 01 Feb 2007 06:18:08 -0800, Cam wrote:
On Feb 1, 8:37 am, "Joe LoBuglio" wrote: I recently purchased an aluminum-framed bicycle at a yard sale. I am curious as to the why the rear dropout is designed the way it is. It is cantilevered more than I see on other bikes and this seems strange to me. Other bicycles have the wheel axle closer to the junction of the seat and chain stays. This design seems unnecessary and I worry about cracking of an aluminum frame. Pictures are athttp://www.lobuglio.org/redbike/ The bike has no identifying information on it (no head-badge or decals). It was a charity yard sale so the owner wasn't there when I bought it. It has Shimano 105 components with a 7 speed cassette (13-28) and a double chainring up front (52-42) in the back. The rear spacing is 126 mm, so I am guessing this is late 1980's. On the bottom- right chainstay it has "B1-0302" stamped (as if by a dot-matrix printer) and on the left chainstay is the serial number (11 numbers, the first five of which are 65804). I am curious as to the why the rear dropout is designed the way it is (cantilevered) and if anyone might have any guesses as to its origin. Thanks Joe LoBuglio I'd guess it's a Cannondale. They made them that way for looks, small rear triangles were the fast look back then (and it's red!! wooo hoo!). I've got a mid-eighties Cannondale m700 and I don't worry about the cantilevered dropouts cracking, those bikes were over engineered. I'm sure someone else can help you with the serial numbers. Year and model are encoded in there somehow. Cam I think those frames do have a reputation for failing. See, for instance, this rbt thread: http://tinyurl.com/2l6h7r I think Cannondale marketed this as a weight-saving feature. That's how they got their "2.8" series of frames down to 2.8 pounds. I'm curious if anyone thinks there's a problem with riding it until it fails (if it does fail). I had a chainstay break on one of my bikes and it didn't make me lose control. |
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Cantilevered rear aluminum dropouts
On Feb 1, 9:24 am, M-gineering wrote:
Joe LoBuglio wrote: I recently purchased an aluminum-framed bicycle at a yard sale. I am snip It's a Crack n Fail, aka Cannondale from 94 vintage or thereabouts. The prefered failure mode is through the flattened bottom of the seatstays but as this frame has survived till now it might live a bit longer Thanks, the hints of 2.8 and the Cannondale let me find out more about this frame. As it turns out, it is a 3.0 since the cable is routed above the top tube; the 2.8 had it below the top tube and had more shape to the top tube (from what I read). It was manufactured in 1991. Since it has the flattened seat stays where it is welded to the chain stay, I assume it has the same cracking potential. Joe |
#6
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Cantilevered rear aluminum dropouts
Wasn't this poor design the result of the Klein lawsuit? An attempt
to get around the patent issued to Klein that probably shouldn't have been granted. The one that claimed the ideal bike frame was aluminum tubes of certain diameters. On the fun side, when it fails, the rear wheel will likely just jam in the frame and you will come skiding to an abrupt stop. No endos thank you. Rick |
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Cantilevered rear aluminum dropouts
On Feb 1, 12:22 pm, "
wrote: Wasn't this poor design the result of the Klein lawsuit? An attempt to get around the patent issued to Klein that probably shouldn't have been granted. The one that claimed the ideal bike frame was aluminum tubes of certain diameters. On the fun side, when it fails, the rear wheel will likely just jam in the frame and you will come skiding to an abrupt stop. No endos thank you. Rick The reason this was done (I assume) was so that the fat stays could clear the cassette/chain. I don't think the design is as poor as it may appear because I don't recall many of failing, but others seem to disagree. |
#9
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Cantilevered rear aluminum dropouts
wrote:
The reason this was done (I assume) was so that the fat stays could clear the cassette/chain. I don't think the design is as poor as it may appear because I don't recall many of failing, but others seem to disagree. clearance is poor, the stays needed a severe crimp (on both sides for symmetry ) to clear the chain in top gear, they cracked -- --- Marten Gerritsen INFOapestaartjeM-GINEERINGpuntNL www.m-gineering.nl |
#10
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Cantilevered rear aluminum dropouts
Joe LoBuglio wrote:
I recently purchased an aluminum-framed bicycle at a yard sale. I am curious as to the why the rear dropout is designed the way it is. It is cantilevered more than I see on other bikes and this seems strange to me. Other bicycles have the wheel axle closer to the junction of the seat and chain stays. This design seems unnecessary and I worry about cracking of an aluminum frame. Pictures are at http://www.lobuglio.org/redbike/ The bike has no identifying information on it (no head-badge or decals). It was a charity yard sale so the owner wasn't there when I bought it. It has Shimano 105 components with a 7 speed cassette (13-28) and a double chainring up front (52-42) in the back. The rear spacing is 126 mm, so I am guessing this is late 1980's. On the bottom- right chainstay it has "B1-0302" stamped (as if by a dot-matrix printer) and on the left chainstay is the serial number (11 numbers, the first five of which are 65804). I am curious as to the why the rear dropout is designed the way it is (cantilevered) and if anyone might have any guesses as to its origin. What: Early Cannondale Why: Beats me, just that way. -- Andrew Muzi www.yellowjersey.org Open every day since 1 April, 1971 |
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