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Why are aluminum GT frames so weak?

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Why are aluminum GT frames so weak?

Old 07-24-20, 09:06 PM
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Nahuel_B58
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Why are aluminum GT frames so weak?

Why alluminum GT frames are so weak? I'm leaving some pics here of a GT i bought today in really bad conditions. It's not the first one but as i like parting out bikes so much, i "wrenched" it with my bike and took it home.






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Old 07-24-20, 09:44 PM
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They're great trash material.
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Old 07-24-20, 09:45 PM
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It ain't the years, honey. It's the mileage.
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Old 07-24-20, 11:51 PM
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Originally Posted by General Geoff View Post
It ain't the years, honey. It's the mileage.
i tried to figure out the model but idk, i'm posting a photo of it before being parted out. It was rough, really bad shape.
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Old 07-24-20, 11:58 PM
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Its a 10-20 year old mountain bike that is wrecked. Hardly uncommon.
you could replace the brand and pics with any number of others.
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Old 07-25-20, 05:24 AM
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That bike looks abused, wearing a hole in I'm guessing a chain stay from rubbing on a pedal or tire is hardly the frame's fault. The rear drop outs being worn are not uncommon with aluminum frames.

Aluminum bikes can live a long life. I just converted a maybe 30 year old Cannondale aluminum frame MTB to an ebike. 10 years ago the frame was so worn at the drop out the rear wheel would pull forward with normal riding, I had to fabricate stainless steel plates for the sides of the drop out to get the wheel to stay put.

But other than that it has held up to a 240# rider all these decades. Hopefully it will hold up to the emotor for 20 more.
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Old 07-25-20, 06:36 AM
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My 20 year old Zaskar (last year made in the US) would belie your statement. Other than scratches in the paint from continuous off road use (including a stretch with a mid-drive motor), it's pristine. Will post a photo in a day or so.
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Old 07-25-20, 10:01 AM
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Originally Posted by 2old View Post
My 20 year old Zaskar (last year made in the US) would belie your statement. Other than scratches in the paint from continuous off road use (including a stretch with a mid-drive motor), it's pristine. Will post a photo in a day or so.
we want to see that Zaskar! Do you know the model and year of the bike i showed? I think it could be a 2008 model aprox so that would be something to think about for example, if GT's materials were better back in 1990s, although a friend of mine told me he repaired and saw a lot of 90's GT aluminum bikes being brand new and cracking some weeks after
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Old 07-25-20, 10:10 AM
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Originally Posted by Nahuel_B58 View Post
Why alluminum GT frames are so weak? I'm leaving some pics here of a GT i bought today in really bad conditions. It's not the first one but as i like parting out bikes so much, i "wrenched" it with my bike and took it home.

Is anyone else astonished by how much effort went into grinding a hole that large into a chainstay? That is not a hole that is made on a single ride. That’s not a hole that is made over the course of just a few miles. That’s hundreds of miles riding on a bike that requires a lot of strength to get moving down the road. I wouldn’t have even though you could do that and make the bike move at all. It’s also not something that is easy to do on a bike with vertical dropouts.

On to the issue of the GT being a weak bike, nothing that you have shown on this bike is due to the bike being “weak”. Everything is due to user error...and very hamhanded error at that. A strong frame that has a hole that size burned into the chainstay would break. The dropouts look like someone took a grinding wheel to it in an effort to make the dropouts horizontal. Kind of sad really.
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Old 07-25-20, 10:18 AM
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Treat any mountain bike like a BMX bike and you can break the frame easily. GT aluminum mountain bikes were the toughest bikes on the market in the 1990s, but even they would eventually fail after enough 20-foot drops.
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Old 07-25-20, 11:27 AM
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I don't understand why someone would waste time thinking about that carcass much less taking pics of it.
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Old 07-25-20, 11:27 AM
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Originally Posted by mstateglfr View Post
Its a 10-20 year old mountain bike that is wrecked. Hardly uncommon.
you could replace the brand and pics with any number of others.
from the looks of it, its also been ridden with the quick releases loose.
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Old 07-25-20, 12:12 PM
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You did not just buy a New Bike, right?

Because you thrashed the bike, and they did not use steel , you wanted lighter did you not?

Off road riding is shortening its use life..







...
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Old 07-25-20, 12:22 PM
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Originally Posted by shelbyfv View Post
I don't understand why someone would waste time thinking about that carcass much less taking pics of it.
idk, for me it's interesting to see the damage some bikes have and then figuring out the motive. I think that dropouts were the first ones to fail and then as the wheel was twisted, it "burned" the aluminum. Apart from the frame the bike was one of the worst i have seen, previous owner must be Hulk 😝
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Old 07-25-20, 12:25 PM
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Originally Posted by fietsbob View Post
Because you thrashed the bike, and they did not use steel , you wanted lighter did you not?

Off road riding is shortening its use life..







...
i bought it just to part it out so my preferences did not apply when buying it. If u ask me, i would prefer a 98' Palomar made of chromoly
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Old 07-25-20, 01:25 PM
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Looks like it spent considerable time with a street person.
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Old 07-25-20, 02:33 PM
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Bad picture. Just de-motorized (mid-drive BBS02) 2000 Zaskar, then needed to have the bottom bracket chased.

Don't know much about other GT model years, but the C&V guys are experts.
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Old 07-25-20, 11:40 PM
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Originally Posted by Nahuel_B58 View Post
idk, for me it's interesting to see the damage some bikes have and then figuring out the motive. I think that dropouts were the first ones to fail and then as the wheel was twisted, it "burned" the aluminum. Apart from the frame the bike was one of the worst i have seen, previous owner must be Hulk 😝
You asked why all aluminum gt frames so weak. Its been stated by all others besides you that they arent and thst this example is due to misuse/abuse.

Your theory as to how holes were created is absurd.

You mentioned you bought this bike to part out, yet you also posted that besides the frame(that is broken and you make fun of) the bike was one of the worst you've seen. Why would you buy a bike to part out that has a trashed frame and parts thst are even worse?
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Old 07-26-20, 03:33 PM
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Originally Posted by mstateglfr View Post
You asked why all aluminum gt frames so weak. Its been stated by all others besides you that they arent and thst this example is due to misuse/abuse.

Your theory as to how holes were created is absurd.

You mentioned you bought this bike to part out, yet you also posted that besides the frame(that is broken and you make fun of) the bike was one of the worst you've seen. Why would you buy a bike to part out that has a trashed frame and parts thst are even worse?
Because selling the cranks, fork, wheels, handlebar and stem will allow me to triplicate the money i invested in the bike.
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Old 07-26-20, 03:38 PM
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Sounds like a lot of work for $25 profit.
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Old 07-27-20, 07:06 AM
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Waste of digital film.
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