Re: Bottom Bracket frame failure



W

Werehatrack

Guest
On 10 Apr 2005 07:47:49 -0700, [email protected] wrote:

>I just bought a vintage Torpado Superlight frame from about 1985.
>This frame is made of Columbus SLX tubing and was their top of the line
>
>frame from that time. The frame is in very nice condition with no rust
>and a clean bottom bracket shell. The bottom bracket shell is an
>english threaded Cinelli. Torpado cut a decorative "T" in the bottom
>bracket shell that measures about 2cm X 2cm. When my LBS professional
>looked the frame over, he was critical of the cutout. He told me that
>Torpado went out of business because of bottom bracket frame failures.
>He felt that the cutout in the bottom of the shell might cause failure
>if standing on the pedals. Does anyone have any experience with this
>issue? Especially with Torpadoes? Another employee felt that this issue
>
>diminished with the use of a modern cartridge bottom bracket. Any
>opinions from the group would be appreciated. Thanks in advance.


If you're at all concerned, make sure that it has a cartridge-type BB
installed, and forget about it. Lots of bikes have a hole in the BB
shell. The part of the shell that's stressed heavily is the area
around the tube joints. The bottom of the shell is unlikely to fail
in heavy service, even with a T-shaped cutout of the size you
describe. I should note that hundreds of thousands (at least) of
bikes sold in the US had a BB shell that was made from mild steel that
was not even seamless; there was a seam across the bottom which was
either unfused or poorly brazed, and those BB shells still don't fall
apart after many years of being ridden. A mere cutout in a sound tube
is not going to cause the tube to fail any more easily than those
would have.

As for the statement of BB shell breakage being the reason that
Torpado went under, it's not. They fell victim to the shrinking
market for and falling profitability of non-exotic bikes made outside
of China/Taiwan/etc. This has been reducing the number of makers for
several decades.
--
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