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Framebuilders Thinking about a custom frame? Lugged vs Fillet Brazed. Different Frame materials? Newvex or Pacenti Lugs? why get a custom Road, Mountain, or Track Frame? Got a question about framebuilding? Lets discuss framebuilding at it's finest.

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Old 04-10-16, 04:38 AM   #1
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BB strength

I bought a Trek 920 recently. The shift cables are run interior, rear brake housing runs exterior. The exit opening just above the BB shell is about 5 cm, by about 1/4 in. , full width of the down tube which seems to be 5x5 cm squarish. I've heard BBs are more about lateral strength. Should I be concerned about BB integrity?
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Old 04-10-16, 05:11 AM   #2
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I bought a Trek 920 recently. The shift cables are run interior, rear brake housing runs exterior. The exit opening just above the BB shell is about 5 cm, by about 1/4 in. , full width of the down tube which seems to be 5x5 cm squarish. I've heard BBs are more about lateral strength. Should I be concerned about BB integrity?
Thanks!!
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Old 04-10-16, 10:11 AM   #3
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Looks pretty strong to me.
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Old 04-10-16, 10:54 AM   #4
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I would have zero concerns. The bottom of the down tube laps the BB shell and the welds at the BB shell edges look really beefy.
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Old 04-10-16, 06:17 PM   #5
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I would have zero concerns. The bottom of the down tube laps the BB shell and the welds at the BB shell edges look really beefy.






thank you for your opinion. I have great respect to you from reading your previous posts.
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Old 04-10-16, 07:02 PM   #6
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In theory when compared to a DT that contacted the shell on center (and presumably was fully joined) there will be a lesser stiffness. But in practice these bikes are rather over built and already far stiffer then what we rode when we were young. I think the same can be said for strength too. Andy.
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Old 04-10-16, 07:54 PM   #7
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when you were describing the hole, I had a hard time believing it. But it does look fine. Maybe we'll know in 20 years
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