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Old 06-06-11, 08:52 AM   #1
c_booth
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Pre braze tube deflection

I noticed today while marking up a Zona tubeset ready for mitering that the downtube (650mm length) has a bit of a bend. When held down at one end, the other end is off the table by about 2mm.

Now I don't expect bicycle tubing to be perfectly straight - a tenth of a mm or two here or there is to be expected - but is a 2mm deflection enough to be considered faulty goods, and should I be looking to send it back to the supplier? Or is this perfectly normal, and I just continue with the build, being sure to position the tube so that the bend is set vertically, and cold set if necessary?
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Old 06-06-11, 01:30 PM   #2
Live Wire 
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Even though 90% of tubes have some bow to them, 2mm is perhaps a tiny bit more than usual. Doesn't matter though, as long as you orient the deflection vertically, it won't present an alignment problem.
A little anectdotal FWIW, I've found Columbus and Deda tubes to have more bow than True Temper...must have something to do with with the drawing vs rolling processes.
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Old 06-07-11, 04:59 AM   #3
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Quote:
Originally Posted by Live Wire View Post
Even though 90% of tubes have some bow to them, 2mm is perhaps a tiny bit more than usual. Doesn't matter though, as long as you orient the deflection vertically, it won't present an alignment problem.
A little anectdotal FWIW, I've found Columbus and Deda tubes to have more bow than True Temper...must have something to do with with the drawing vs rolling processes.


Thanks Live Wire. Yeah I'd figured 2mm prob sat in the grey area between 'acceptable' deflection and 'banana'. I'd rather not go through the hassle of sending it back if it's not absolutely necessary, so I'll prob just go ahead and use it. Not ideal but.....

Interesting point regarding drawing vs rolling - been thinking about True Temper for my next frame actually (haven't used it yet) so I'll be intrigued to see if there's any noticeable difference (if anything can be discerned from a 4 tube sample).
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