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Frame cracks here!

Old 08-02-19, 11:40 PM
  #1  
Nahuel_B58
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Frame cracks here!

Made this post for us to post cracked frames we saw. The other day i was looking for a GT where we recycle bikes for people and that poor GT was ruined. Disc brakes and front suspension but two awful cracks.

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Old 08-03-19, 07:51 AM
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spinnaker
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There ws a good reason someone tossed it out. Not worth saving.
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Old 08-03-19, 10:45 AM
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GamblerGORD53
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That chain is rusty, so it's been outside a while.
Plus that appears to be one of those gawd awful bikes with a TT so sloped it merges with the seat stay in an almost straight line. What a STUPID plan. The triangle has ZERO strength. Durability has NO relevance to these braindead companies.
And yet millions are mindlessly buying these garbage bikes.
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Old 08-03-19, 10:49 AM
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Originally Posted by GamblerGORD53 View Post
That chain is rusty, so it's been outside a while.
Plus that appears to be one of those gawd awful bikes with a TT so sloped it merges with the seat stay in an almost straight line. What a STUPID plan. The triangle has ZERO strength. Durability has NO relevance to these braindead companies.
And yet millions are mindlessly buying these garbage bikes.
I don't think that is triple triangle hold's fault. Never saw a 1990's triple triangle GT crack, although, i saw lots of new ****ty Agressor being cracked there or in the dropout. Maybe it's because of bad materials or just some folks believing that a base version GT is able to go mountain biking and there you have the results.
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Old 08-03-19, 06:09 PM
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AnthonyG
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Who knows. It may have been some teenager trying out a radical stunt in a skate park or urban setting. The frame may look bad but doesn't compare to the riders broken arm.
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Old 08-03-19, 07:58 PM
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Originally Posted by GamblerGORD53 View Post
Plus that appears to be one of those gawd awful bikes with a TT so sloped it merges with the seat stay in an almost straight line. What a STUPID plan. The triangle has ZERO strength.
Lots of (most?) BMX bikes have top tubes almost in line with the seat stays. Doesn't seem to be a weak design or they'd be cracking up all over the tracks.
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Old 08-04-19, 06:02 AM
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Coincidentally (I assume), the only frame I ever had crack was also black GT mtn frame. The bike was near-new, and set up with road-friendly tires and used as a road bike, so it didn't see ANY rough use. Then one day, I find a crack at a weld.
I believe I got it from Cambria, who I contacted, but they left me high and dry, and I've been turned off to them ever since..
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Old 08-04-19, 06:09 AM
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Posting random pictures of cracked frames without knowing anything about the cause or circumstances is a great idea
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Old 08-04-19, 06:48 AM
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Failure at the disk brake mount suggests that the stays were not sufficiently robust to handle the brake torque. Thicker tubing and/or gussets may have prevented this.
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Old 08-04-19, 08:32 AM
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Originally Posted by JohnDThompson View Post
Failure at the disk brake mount suggests that the stays were not sufficiently robust to handle the brake torque. Thicker tubing and/or gussets may have prevented this.
I doubt that the brake torque alone is sufficient to break a frame. More likely the bike has seen jumps and landings too harsh for it to handle.
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Old 08-04-19, 09:19 AM
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I've seen a 90's GT rear frame cracked around both rear brake mounts. 7005, thin wall.

The one in the picture is missing a vital brace link between the seat stay and chain stay. So fatigue was inevitably going into the metal on braking alone, without even seeing the frame design. The weld is stronger than the tube because it's thicker, the tube spreads the stress everywhere along it except where it meets the weld, so metal will almost always fatigue/crack at the edge of a weld, where flex meets rigidity.

Absolutely no surprise this frame has snapped there. One will have cracked first, the rider not detected it, then when the other cracked they both went completely.
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Old 08-04-19, 05:16 PM
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i don't get it
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Old 08-04-19, 05:19 PM
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The bike was donated a year ago maybe so some pieces may be used in another bike before i saw this bike. Is a GT Chucker. On tuesday i'll be parting out it.
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